{"paper_id":"d9925dac-4d06-452b-bebf-944fe2280e4a","body_text":"IntechOpen Series  \nObstetrics and Gynecology, Volume 7\nA Comprehensive Overview \nof Endometriosis\nEdited by Wei Wu and Rong Ju\nEdited by Wei Wu and Rong Ju\nA Comprehensive Overview of Endometriosis explores the complexities of this chronic \ngynecological condition, offering readers a deep understanding of its many facets. \nThe book examines various elements of endometriosis, such as environmental risk \nfactors, symptoms, causes, underlying biological processes, diagnosis, molecular \nmechanisms, treatment options, and prevention strategies. It presents valuable \ninsights into different treatment methods, including hormonal therapies that \naddress the hormonal aspects of the condition and surgical options tailored to the \ndisease’s severity and location. Furthermore, the book discusses multidisciplinary \napproaches to pain management for women affected by endometriosis, emphasizing \nthe influence of environmental factors and epigenetic mechanisms. With its \nauthoritative content, A Comprehensive Overview of Endometriosis is a crucial resource \nfor medical professionals looking to improve their understanding and enhance \npatient outcomes, researchers committed to expanding knowledge in this area, and \npatients seeking to understand their condition better. This book is essential for \nanyone involved in diagnosing, treating, and managing endometriosis, offering a \nthorough and current overview of this intricate condition.\nPublished in London, UK  \n©  2025 IntechOpen \n©  Md Saiful Islam Khan / iStock\nISBN 978-0-85014-733-9\nZouhair O. Amarin,  \nObstetrics and Gynecology Series Editor\nISSN  3049-706X\nA Comprehensive Overview of Endometriosis\n\n\n\nA Comprehensive \nOverview of \nEndometriosis\nEdited by Wei Wu and Rong Ju\nPublished in London, United Kingdom\n\nA Comprehensive Overview of Endometriosis\nhttp:/ /dx.doi.org/10.5772/intechopen.1000479\nEdited by Wei Wu and Rong Ju\nContributors\nAli Emami, Ana Maria Apetrei, Ana Maria Haliciu, Andreea Ioana Pruteanu, Ashish Ashish, Balansama \nMarah, Daniela Rangel-Santos, Feng Wu, German William Rangel, Gunjan Rai, Haonan Shi, Hongshan Ge, \nIoana Pavaleanu, Jing Wei, Jinqi Ma, Kusum Kusum, Lei Chen, Merve Konal, Peihao Wu, Qi Liu, Qinrou \nChen, Qiuqin Tang, Raluca Anca Balan, Razvan Socolov, Rong Ju, Royana Singh, Sangeeta Rai, Shivani \nMishra, Sia Florence Koroma, Sudhir Diwan, Teodora Ana Balan, Tiberiu Nicolae Poparlan, Tongfei Yang, \nTudor Andrei Butureanu, Wei Wu, Xuan Jin, Ying Li, Ziyi Zhang\n© The Editor(s) and the Author(s) 2025\nThe rights of the editor(s) and the author(s) have been asserted in accordance with the Copyright, \nDesigns and Patents Act 1988. 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The publisher assumes no responsibility for \nany damage or injury to persons or property arising out of the use of any materials, instructions, \nmethods or ideas contained in the book.\nFirst published in London, United Kingdom, 2025 by IntechOpen\nIntechOpen is the global imprint of INTECHOPEN LIMITED, registered in England and Wales, \nregistration number: 11086078, 167-169 Great Portland Street, London, W1W 5PF, United Kingdom\nFor EU product safety concerns: IN TECH d.o.o., Prolaz Marije Krucifikse Kozulić 3, 51000 Rijeka, \nCroatia, info@intechopen.com or visit our website at intechopen.com.\nBritish Library Cataloguing-in-Publication Data\nA catalogue record for this book is available from the British Library\nA Comprehensive Overview of Endometriosis\nEdited by Wei Wu and Rong Ju\np. cm.\nThis title is part of the Obstetrics and Gynecology Book Series, Volume 7\nTopic: Reproductive and Gynecologic Health\nSeries Editor: Zouhair O. Amarin  \nTopic Editor: Courtney Marsh\nPrint ISBN 978-0-85014-733-9\nOnline ISBN 978-0-85014-732-2\neBook (PDF) ISBN 978-0-85014-734-6\nISSN 3049-706X\nIf disposing of this product, please recycle the paper responsibly.\n\nSelection of our books indexed in the Book Citation Index \nin Web of Science™ Core Collection (BKCI)\nInterested in publishing with us? \nContact book.department@intechopen.com\nNumbers displayed above are based on latest data collected. \nFor more information visit www.intechopen.com\n156\nCountries delivered to\n12.2%\nContributors from top 500 universities\nOur authors are among the\nTop 1%\nmost cited scientists\nWe are IntechOpen,\nthe world’ s leading publisher of \nOpen Access books\nBuilt by scientists, for scientists\nBOOK\nCITATION\nINDEX\n \nCLARIVATE ANALYTICS\nIN D E X E D\n7,500+ \nOpen access books available\n196,000+\nInternational  authors and editors\n215M+ \nDownloads\n\n\n\nIntechOpen Book Series  \nObstetrics and Gynecology\nV olume 7\nAims and Scope of the Series\nObstetrics and Gynecology field typically covers several subspecialties that include \nmaternal-fetal medicine, gynecologic oncology, reproductive endocrinology and \nsubfertility, urogynecology and female pelvic reconstructive surgery, critical care \nmedicine, complex family planning, pediatric and adolescent gynecology, meno-\npausal and geriatric gynecology, and minimally invasive gynecologic surgery. \nApart from being diverse, obstetrics and gynecology is a challenging and demand-\ning specialty. It combines medical and surgical skills.\nThe sequence of books in this series will have certain characteristics in common that \nwill be recognized as part of the same informative multi-volume book programme. \n\n\n\nMeet the Series Editor\nZouhair Amarin is a Professor of Obstetrics and Gynaecology at \nthe Jordan University of Science and Technology. He was previ-\nously a lecturer at the University of Glasgow , Scotland, a senior \nlecturer at the University of Nottingham, England, and the dean \nof the Faculty of Medicine at Mutah University, Jordan. Professor \nAmarin is a fellow of the Royal College of Obstetricians and Gy-\nnaecologists, and the Faculty of Public Health, London. He holds \nmaster’ s degrees in medical science and medical education. He is a pioneer in IVF and \nwas the first in the world to develop microsurgical epididymis sperm aspiration for \nclinical use. He also discovered a surgical procedure for critical ovarian hyperstim-\nulation syndrome. Professor Amarin has edited books, authored book chapters, and \npublished more than 130 papers. He is the recipient of eight awards. \n\n\n\n\nDr. Wei Wu is a Professor at the School of Public Health and the \nVice Dean of the School of International Education at Nanjing \nMedical University, China. He has served as a guest researcher at \nthe National Institute of Environmental Health Sciences (NIEHS). \nDr. Wu is an active member of various national and internation-\nal societies in the fields of human reproduction and toxicology, \nand he has received numerous awards from prestigious organiza-\ntions for the originality and quality of his research projects. Dr. Wu has authored 90 \npeer-reviewed papers in international journals, achieving an H-index of 30. In ad -\ndition to his research contributions, he has edited nine books and contributed to ten \nother volumes. He holds 20 patents and has organized six international conferences. \nFurthermore, he serves as a reviewer for 112 academic journals.\nDr. Rong Ju is the Vice Director of Nanjing Jiangning Hospital. She \nhas been engaged in clinical and teaching in obstetrics and gyne-\ncology for over 20 years, focusing on research in gynecological re -\nproductive endocrinology, endometriosis, infectious diseases, and \nhospital management. Dr. Ju is an active member of various societ-\nies in the fields of human reproduction, endocrinology, obstetrics \nand gynecology, and developmental biology. She has presided over \n10 research projects and published over 30 papers.\nMeet the V olume Editors\n\n\n\nPreface XV\nChapter 1 1\nDecoding Endometriosis: A Comprehensive Guide to Understanding \nSymptoms and Impacts\nby Ali Emami\nChapter 2 15\nEndometriosis-Associated Ovarian Carcinoma\nby Ioana Pavaleanu, Teodora Ana Balan, Tiberiu Nicolae Poparlan, \nAna Maria Haliciu, Tudor Andrei Butureanu, Ana Maria Apetrei,  \nRazvan Socolov , Andreea Ioana Pruteanu and Raluca Anca Balan\nChapter 3 43\nMedical Treatment for Endometriosis\nby Merve Konal\nChapter 4 57\nPain Management for Women with Endometriosis\nby Daniela Rangel-Santos, German William Rangel and Sudhir Diwan\nChapter 5 79\nAdvances in Endometriosis Research: From Pathogenesis to Prevention\nby Ashish Ashish, Shivani Mishra, Sangeeta Rai, Kusum Kusum, Gunjan Rai \nand Royana Singh\nChapter 6 111\nFrom Environmental Exposure Risk to Epigenetic Factors: What Role Do  \nThey Play in the Etiology of Endometriosis?\nby Qinrou Chen, Tongfei Y ang, Peihao Wu, Qi Liu, Feng Wu, Haonan Shi,  \nZiyi Zhang, Balansama Marah, Sia Florence Koroma, Xuan Jin, Lei Chen,  \nYing Li, Jinqi Ma, Rong Ju, Jing Wei, Hongshan Ge, Qiuqin T ang and Wei Wu\nContents\n\n\n\nPreface\nEndometriosis is a complex and often misunderstood gynecological condition that \npresents significant challenges for medical professionals and the millions of women \naffected globally . As the editor of this comprehensive volume, I am pleased to present \na carefully curated collection of chapters that explore the intricate nature of endome-\ntriosis, covering aspects from its pathogenesis and diagnosis to treatment options and \nthe broader implications for patients’ lives.\nChapter 1 comprehensively reviews the diverse symptoms of endometriosis, covering \ngastrointestinal, urogenital, thoracic, cutaneous, and neurological manifestations. It \nhighlights diagnostic challenges and their impact on quality of life, emphasizing the \nneed for accurate diagnostic tools and personalized treatment strategies.\nChapter 2 explores endometriosis-associated ovarian carcinoma (EAOC), examining \nits epidemiological links, molecular mechanisms, and clinical implications. It high-\nlights risk factors, pathological characteristics, and the distinct subtypes of EAOC, \nemphasizing the importance of early detection and targeted treatments.\nChapter 3 offers a comprehensive overview of medical treatments for endometriosis, \ncovering hormonal therapies, non-hormonal treatments, emerging approaches, \nand lifestyle modifications. It emphasizes personalized treatment strategies and the \nimportance of patient education for long-term management.\nChapter 4 comprehensively reviews pain management strategies for women with \nendometriosis, covering pharmacological treatments, interventional techniques, and \nadjuvant therapies. This comprehensive review underscores the need to integrate \ndifferent treatment modalities to address the diverse symptoms and challenges these \npatients face, ensuring a more holistic and effective pain management.\nChapter 5 comprehensively reviews recent advances in endometriosis research, from \ngenetic factors and environmental influences to emerging technologies and personal-\nized medicine approaches.\nChapter 6 explores the role of environmental exposures and epigenetic factors in \nendometriosis, discussing how these elements influence disease development and \npotential applications in diagnosis and treatment.\nThroughout the writing process, I have had the honor of collaborating with a dedi-\ncated team of co-editors and contributors, each offering their unique expertise and \nperspectives. Their combined efforts have been crucial in producing a comprehen-\nsive and authoritative resource on endometriosis. I would like to thank Mrs. Maja \nBozicevic at IntechOpen for her strong support from the inception to the completion \nof this book. The completion of this book was made possible with the support of the \n\nNoncommunicable Chronic Diseases-National Science and Technology Major Project \n(2023ZD0507401).\nIn conclusion, A Comprehensive Overview of Endometriosis is designed to be a valuable \nresource for medical professionals, researchers, and patients. W e hope the informa -\ntion in this work will enhance understanding of endometriosis, encourage further \nresearch, and ultimately improve diagnosis, treatment, and support for individuals \naffected by this complex condition.\nW ei Wu\nSchool of Public Health,\nNanjing Medical University ,\nChina\nRong Ju\nThe Affiliated Jiangning Hospital of Nanjing Medical University ,\nNanjing Medical University ,\nChina\nIVXVI\n\n1\nChapter 1\nDecoding Endometriosis: \nA Comprehensive Guide to \nUnderstanding Symptoms and \nImpacts\nAli Emami\nAbstract\nUp to 10% of all women suffer with endometriosis, a chronic inflammatory \ngynecological condition, that is dependent on estrogen. This prevalence rises \nto 30–50% among women who experience infertility and/or severe pelvic pain. \nEndometriosis is a disease that is remarkably underdiagnosed and undertreated \ndue to a lack of exact knowledge about it. It takes an unreasonable amount of time \n(8–12 years) between the onset of symptoms and a conclusive diagnosis. This is due \nto the fact that the majority of the symptoms are non-specific and there are no non-\ninvasive diagnostic procedures that can offer a conclusive diagnosis. These days, \nassessing all symptoms and indicators that may lead us to question the presence of \nendometriosis is crucial. W e will investigate all symptoms of this disorder in this \nchapter.\nKeywords: endometriosis, symptoms, signs, fatigue, chronic pelvic pain\n1.  Introduction\nEndometriosis is a persistent inflammatory , estrogen-dependent disorder charac -\nterized by the growth of endometrial-like tissue outside the uterine cavity [1, 2]. This \ncondition affects an estimated 175 million women of reproductive age worldwide [3].\nEndometriosis is estimated to affect one in ten Australian women of reproductive \nage, incurring direct medical and surgical costs exceeding $6 billion annually for \nwomen over 18 years old [4]. The definitive diagnosis of endometriosis necessitates \nlaparoscopy and histopathology [5]. For many women, the interval between the onset \nof symptoms and diagnosis can exceed 8 years. Consequently , there is significant \ninterest in identifying clinical features that could predict the presence of endometrio-\nsis and reduce the delay in commencing active treatment [6].\nEndometriosis is influenced by several known risk factors, including early men-\narche, late menopause, short menstrual cycles, low body mass index (BMI), and low \nparity [7 , 8]. The etiopathogenesis of endometriosis remains not fully understood. \n\nA Comprehensive Overview of Endometriosis\n2\nPotential contributing factors include uterine hyperperistalsis and hyperestrogenism, \nalongside genetic factors, the implantation theory , and cellular metaplasia [9, 10].\nIt is widely believed that the extent of anatomical distortion caused by adhe-\nsions and fibrosis from endometriosis correlates with higher incidences of infertil-\nity . Additionally , soluble factors such as inflammation, oxidative stress, hormonal \nabnormalities, and immune dysregulation play significant roles in infertility among \nendometriosis patients. Chronic wounds, including those from endometriosis, \ndiabetic foot ulcers, and other non-healing conditions, undergo recurrent tissue \ndamage and repair cycles [11, 12]. In endometriosis, fibrosis is induced by inflamma -\ntory responses, leading to processes like epithelial-mesenchymal transition (EMT), \nfibroblast-myofibroblast transdifferentiation (FMT), and smooth muscle metaplasia \n(SMM), perpetuating the cycle of wound healing and tissue remodeling [13, 14].\nThe classical clinical presentation of endometriosis includes dysmenorrhea, \ndyspareunia, infertility , and menstrual cycle-related lower abdominal pain. These \nsymptoms can guide clinicians toward the correct diagnosis [15, 16]. However, \nin Germany , endometriosis is often diagnosed with a delay of up to 10 years, \nprimarily due to misdiagnosis. This issue is particularly pronounced in cases of \nextragenital endometriosis (EE), which affects approximately 9% of women with \nendometriosis [17].\nEE cases are frequently first presented to non-gynecological specialties, leading \nto delayed diagnosis and chronic pain, which can dysregulate the nervous system and \ncause abnormal pain patterns. This necessitates a more complex differential diag -\nnosis process, having significant physical, psychological, and social impacts. Early \nrecognition and proper treatment initiation are crucial [18, 19]. Recent research has \nconcentrated on identifying reliable biomarkers for endometriosis, encompassing a \nwide range of indicators. These include immunologic markers such as immune cells, \nantibodies, and cytokines, as well as genetic and biochemical markers like microR-\nNAs, long non-coding RNAs (lncRNAs), circulating and mitochondrial nucleic acids. \nAdditionally , some hormones, glycoproteins, and signaling molecules have also been \nidentified as potential biomarkers [20, 21].\nThe diagnostic process begins with a thorough clinical history , exploring whether \nsymptoms correlate with menstrual cycle phases. Clinical examination includes \nspeculum examination, palpation (including rectovaginal palpation), transvaginal \nultrasound, and renal ultrasound. Diagnostic laparoscopy is the gold standard for \nhistological confirmation [22].\nIdentifying superficial diseases, peritoneal lesions, or early/mild deep endo-\nmetriosis through imaging techniques remains challenging, which suggests that a \nnegative result does not exclude the presence of endometriosis. However, transvaginal \nsonography (TVS) and magnetic resonance imaging (MRI) are effective for detect -\ning more advanced stages of the condition. Severe endometriosis is characterized by \nextensive adhesions to surrounding organs, such as significant inflammatory adhe-\nsions between ovarian endometrioma and the rectum. TVS is particularly valuable \nfor diagnosing adhesions via dynamic manipulation of pelvic organs, where reduced \novarian mobility and limited sliding between the posterior uterine serosa and bowel \nindicate adhesion presence [23, 24].\nW omen displaying TVS signs of ovarian endometriomas exhibit higher levels \nof ovarian immobility than those without these features, with a sensitivity and \nspecificity of 89% and 90%, respectively [25, 26]. The capacity of MRI to detect \nadhesions and obliteration of the pouch of Douglas is similar to that of dynamic TVS, \nwhich diminishes the necessity for routine MRI following TVS. Thus, the diagnostic \n\n3\nDecoding Endometriosis: A Comprehensive Guide to Understanding Symptoms and Impacts\nDOI: http://dx.doi.org/10.5772/intechopen.1008252\nprecision of dynamic TVS rivals may even surpass, that of routine MRI, although \nMRI offers greater objectivity and reproducibility . Both TVS and MRI serve as critical \ntools in assessing the severity of endometriosis, particularly in identifying adhesions, \nand may contribute to establishing a classification for endometriosis-associated pain. \nConversely , a major challenge remains unresolved regarding endometriosis-related \ninfertility , as imaging techniques focused on structural anomalies may not correlate \nwith the progression of infertility severity [25, 27 , 28].\nDue to the chronic nature of endometriosis, a long-term, personalized treatment \nplan is essential, encompassing both conservative (symptomatic and hormonal) \nand surgical treatments, with the potential integration of complementary medicine. \nSurgical indications include organ destruction, differential diagnosis for sterility , and \npersistent pain, with a goal of complete laparoscopic resection where possible. Studies \nhave not demonstrated a clear advantage of surgical treatment over pharmacotherapy \nfor endometriosis-associated pain. Pharmacotherapy aims to achieve secondary \namenorrhea, with dienogest being the first-line drug. Other options include com-\nbined oral contraceptives, gonadotropin-releasing hormone (GnRH) analogs, and \nlocal progestins. In order to lower the likelihood of recurrence, hormonal therapy is \nadvised following surgery , unless pregnancy is urgently wanted [9].\n2.  Gastrointestinal symptoms\nBowel endometriosis is defined by the presence of endometriotic lesions that \ninfiltrate at least the muscular layer of the intestinal wall [29]. Superficial endome-\ntriotic lesions, which only penetrate the intestinal serosa, should not be classified as \nbowel endometriosis and are generally asymptomatic. This condition is estimated to \naffect between 5% and 25% of patients diagnosed surgically with endometriosis [30]. \nThe majority of bowel endometriotic nodules are located at the rectosigmoid junction \nand rectum (65.7%); however, lesions can also be noted in the sigmoid colon (17 .4%), \ncaecum and ileocecal junction (4.1%), appendix (6.4%), and omentum (1.7%) [31].\nPatients with bowel endometriosis typically experience pain and intestinal \nsymptoms. The pain can be attributed to the intestinal nodules as well as other deep \nendometriotic nodules, such as those found in the rectovaginal septum, uterosacral \nligaments, and parametrium, which are often associated with intestinal lesions. In \naddition, the location, size, and degree of intestinal lumen stenosis of bowel nodules \nmight result in a range of intestinal symptoms (Figures  1 and  2) [32].\nPatients with rectosigmoid endometriosis may present with a range of intestinal \nsymptoms, including dyschezia, cyclic bowel alterations, abdominal cramping, a \nsensation of incomplete evacuation, stool fragmentation, the passage of mucus with \nstools, and rectal bleeding [33].\nThe most common complaints among patients included constipation (40%), a \nfeeling of incomplete evacuation (36%), and stool fragmentation (52%). The severity \nof dyschezia, as measured on a 10-point visual analog scale, averaged 7 .1. Patients \nwith deep endometriosis infiltrating the rectum were more likely to experience cyclic \ndefecation pain (67 .9%) and cyclic constipation (54.7%), and they also exhibited \na significantly longer time to evacuate stools. However, these symptoms were also \nprevalent in other groups studied, with 38.1% and 33.3% for the superficial endome-\ntriosis group, and 42.9% and 26.2% for the group with deep endometriosis sparing \nthe rectum, respectively . W omen with rectal endometriosis were also more prone to \nappetite disorders [34].\n\nA Comprehensive Overview of Endometriosis\n4\nFigure  1. \nCecal endometriotic nodule (arrow) [32].\nFigure  2. \nIleal endometriotic nodule (arrowhead) [32].\n\n5\nDecoding Endometriosis: A Comprehensive Guide to Understanding Symptoms and Impacts\nDOI: http://dx.doi.org/10.5772/intechopen.1008252\nThe pain and intestinal symptoms associated with rectosigmoid endometriosis \nare nonspecific, often leading to diagnostic challenges. Prior to receiving a defini-\ntive diagnosis, patients with endometriosis are frequently misdiagnosed with con-\nditions such as irritable bowel syndrome (IBS). An Australian study examined the \nintestinal symptoms of patients with endometriosis, highlighting these diagnostic \ncomplexities [35].\nIleocecal endometriosis may manifest as intestinal obstruction, intussusception, \nor ileocecal perforation, leading to symptoms such as intestinal cramps, vomiting, \nabdominal distention, and catamenial subocclusion [36–39]. In some cases, ileoce-\ncal endometriosis can cause nonspecific symptoms that resemble those of intestinal \nmalignancies or Crohn’ s disease. While magnetic resonance imaging and computed \ntomography may detect an ileocecal mass, they do not always conclusively indicate \nendometriosis [32].\nDouble-contrast barium enema is ineffective at detecting small extraluminal \nlesions. Occasionally , isolated ileocecal endometriosis may be asymptomatic and can \npresent as a submucosal polyp during screening colonoscopy [40]. There have been \ndocumented cases of ileocecal perforation related to endometriosis occurring during \npregnancy and postpartum. Due to the high vascularization of ectopic endometriotic \ntissue, ileocolic perforation during pregnancy can lead to significant intraperitoneal \nhemorrhage [41, 42].\nAppendiceal endometriosis occurs in approximately 2.6% of patients undergoing \nsurgery for endometriosis [43]. The diagnosis of appendiceal endometriosis is often \nmade incidentally during surgery for endometriosis-related pain, without preopera -\ntive suspicion of its presence on the appendix. However, in some patients, gross \nalterations of the appendix may necessitate a selective appendectomy [44].\nAppendiceal endometriosis can mimic acute appendicitis, presenting with symp-\ntoms such as fever, right lower quadrant pain, nausea, and vomiting, and signs such \nas pain at McBurney’ s point [45]. There have been reports of appendiceal perforation \ndue to endometriosis [46]. The acute inflammation is often a result of endometriosis \ncausing partial or complete occlusion of the appendiceal lumen. Rarely , endometrio-\nsis can result in appendiceal intussusception as well [47].\n3.  Urogenital symptoms\nUrogenital tract endometriosis (UGE) is the second most common form of EE, \nprimarily affecting the bladder (over 85% of cases) and, less frequently , the ureters \n(10%), kidneys (4%), and urethra (2%) [48].\nIt typically occurs in women aged 30 to 45 years, with prior pelvic surgery considered \na risk factor. Familial aggregation has also been reported [49]. UGE can be asymptomatic \nin up to 50% of cases, though it can lead to significant complications such as complete loss \nof kidney function in severe cases of ureteral endometriosis [50].\nBladder endometriosis may present with dysuria, recurrent urinary tract infec -\ntions, hematuria, irritable bladder symptoms, vesical tenesmus, and incontinence. \nAbout 40% of women with bladder endometriosis experience perimenstrual symp-\ntoms. Ureteral endometriosis, which affects about 15% of patients, may present with \ncostovertebral angle pain or hematuria [48, 51, 52].\nSurgery is advised for bladder endometriosis lesions, and hydronephrosis is a clear \nsign that surgery is necessary . Re-implantation and ureteral excision are further treat -\nment options, with ureterolysis being successful in 86.7% of cases [51].\n\nA Comprehensive Overview of Endometriosis\n6\n4.  Thoracic symptoms\nThoracic endometriosis (TE) is a rare form of endometriosis affecting the \ndiaphragm ( Figure 3) (44.5%), pleura (12.7%), and lungs (4.5%), often involving \nmultiple structures simultaneously . Genital endometriosis coexists in 53–84% of \nTE cases. TE typically presents around the ages of 30 to 34, about 5 years later than \ngenital endometriosis [18, 53].\nSymptoms include menstrual cycle-related, usually right-sided pain in the tho-\nracic, scapular, or shoulder region, and catamenial pneumothorax [18]. Diagnosis \ninvolves correlating symptoms with menstruation and diagnostic radiology , with MRI \nbeing the preferred modality [54].\nBronchoscopy is useful in cases of hemoptysis to rule out other conditions. \nHistological confirmation is necessary for a definitive diagnosis. Surgical manage -\nment often involves a two-stage approach followed by medical treatment, with \nvideo-assisted thoracoscopic surgery (V ATS) and, in some cases, laparoscopy \n[54–56].\nFigure 3. \nMultiple diaphragmatic endometriosis (the star in picture B is the lung tissue) [22].\n\n7\nDecoding Endometriosis: A Comprehensive Guide to Understanding Symptoms and Impacts\nDOI: http://dx.doi.org/10.5772/intechopen.1008252\n5.  Skin symptoms\nCutaneous scar endometriosis can occur following cesarean delivery , hysterec -\ntomy , or laparoscopy , presenting as nodules in the epifascial tissue. This pathol-\nogy affects less than 1% of women with endometriosis and can be easily excised. \nOverall, endometriosis requires a comprehensive diagnostic and treatment \napproach, tailored to the individual patient’ s needs and clinical presentation  \n[22, 57].\n6.  Neurology symptoms\nNerve involvement, particularly of the sacral plexus, including the sciatic nerve, is \na rare manifestation of EE. Approximately 34% of patients exhibit nerve involvement \nwithout peritoneal lesions. The etiology may involve the development of endometrio-\nsis lesions from undifferentiated cells within the nerve [58].\nSymptoms include cyclic (perimenstrual) sciatica, and prolonged untreated con-\nditions may lead to constant pain and neurological deficits. MRI is the diagnostic tool \nof choice, with ultrasonography as an alternative. Successful drug treatments are rare, \nand surgical excision of parametrial and peritoneal lesions significantly improves \nquality of life and pain symptoms [58, 59].\n7.   Conclusions\nThis comprehensive review of endometriosis symptoms highlights the multifac -\neted nature of the disease, which presents with a wide range of symptoms affecting \nvarious systems including gastrointestinal, urogenital, thoracic, cutaneous, and \nneurological. Despite its prevalence, endometriosis remains underdiagnosed and \nundertreated, with significant delays in diagnosis that can exacerbate patient suffer-\ning and complicate treatment.\nKey findings from this review include the recognition of bowel endometriosis as \na significant source of gastrointestinal symptoms, often misdiagnosed as irritable \nbowel syndrome (IBS). Similarly , urogenital and thoracic endometriosis present with \nsymptoms that are frequently mistaken for other conditions, further complicating \ntimely diagnosis. The review also emphasizes the importance of considering less \ncommon manifestations of the disease, such as nerve involvement and cutaneous scar \nendometriosis, which, though rare, can significantly impact the quality of life.\nThe challenges in diagnosing endometriosis underscore the need for greater \nawareness among healthcare providers and the development of more accurate and \nless invasive diagnostic tools. Additionally , given the chronic nature of endometriosis, \nlong-term management strategies that integrate both medical and surgical approaches \nare essential.\nFuture research should focus on improving diagnostic methodologies, including \nthe development of non-invasive tests, and exploring the pathophysiological mecha -\nnisms underlying the diverse presentations of the disease. Furthermore, clinical \npractice would benefit from a multidisciplinary approach to treatment, tailored to the \nindividual symptoms and needs of patients, to optimize outcomes and improve the \nquality of life for those affected by endometriosis.\n\nA Comprehensive Overview of Endometriosis\n8\nAuthor details\nAli Emami\nQazvin University of Medical Sciences, Qazvin, Iran\n* Address all correspondence to: aliiemamii74@gmail.com\nAcknowledgements\nHereby , we would like to thank the Clinical Research Development Center of \nKowsar Hospital and the Student Research Committee of Qazvin University of \nMedical Sciences, Qazvin, Iran.\nThe author acknowledges the use of ChatGPT by OpenAI and the Grammarly \nW eb site for editing the grammar and punctuation. The authors have not declared a \nspecific grant for this research from any funding agency .\nConflict of interest\nThe author declared no conflict of interest.\n© 2025 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of \nthe Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), \nwhich permits unrestricted use, distribution, and reproduction in any medium, provided \nthe original work is properly cited. \n\nDecoding Endometriosis: A Comprehensive Guide to Understanding Symptoms and Impacts\nDOI: http://dx.doi.org/10.5772/intechopen.1008252\n9\nReferences\n[1] Horne A W , Missmer SA. \nPathophysiology , diagnosis, and \nmanagement of endometriosis. BMJ. \n2022; 379:2-3\n[2] Reis FM, Petraglia F , Taylor RN. \nEndometriosis: Hormone regulation and \nclinical consequences of chemotaxis and \napoptosis. Human Reproduction Update. \n2013;19 (4):406-418\n[3] Adamson GD, Pasta DJ. Endometriosis \nfertility index: The new , validated \nendometriosis staging system. Fertility \nand Sterility . 2010;94 (5):1609-1615\n[4] Bush D, Evans S, V ancaille T . The $6 \nBillion W oman and the $600 Million \nGirl. The Pelvic Pain report. Melbourne: \nPain Australia and the Faculty of Pain \nmedicine; 2011\n[5] Dunselman G, V ermeulen N, \nBecker C, Calhaz-Jorge C, D'hooghe \nT , De Bie B, et  al. ESHRE guideline: \nManagement of women with \nendometriosis. Human Reproduction. \n2014; 29(3):400-412\n[6] Agarwal SK, Chapron C, Giudice LC, \nLaufer MR, Leyland N, Missmer SA, \net  al. Clinical diagnosis of endometriosis: \nA call to action. American Journal \nof Obstetrics and Gynecology . \n2019;220 (4):354.e351-354.e312\n[7] Shafrir AL, Farland L, Shah D, \nHarris H, Kvaskoff M, Zondervan K, \net  al. Risk for and consequences of \nendometriosis: A critical epidemiologic \nreview . Best Practice & Research. Clinical \nObstetrics & Gynaecology . 2018;51 :1-15\n[8] Zhang Y , Ma N- Y . Environmental risk \nfactors for endometriosis: An umbrella \nreview of a meta-analysis of 354 \nobservational studies with over 5 million \npopulations. Frontiers in Medicine. \n2021;8:680833\n[9] Burghaus S, Schaefer SD, \nBeckmann MW , Brandes I, Bruenahl C, \nChvatal R, et  al. Diagnosis and \ntreatment of endometriosis. Guideline \nof the DGGG, SGGG and OEGGG \n(S2k Level, A WMF registry number \n015/045, august 2020). Geburtshilfe und \nFrauenheilkunde. 2021;81(04):422-446\n[10] Signorile PG, Viceconte R, Baldi A. \nNew insights in pathogenesis of \nendometriosis. Frontiers in Medicine. \n2022; 9:879015\n[11] Augoulea A, Mastorakos G, \nLambrinoudaki I, Christodoulakos G, \nCreatsas G. The role of the oxidative-\nstress in the endometriosis-related \ninfertility . Gynecological Endocrinology . \n2009; 25(2):75-81\n[12] Jackson L, Schisterman E, Dey-\nRao R, Browne R, Armstrong D. \nOxidative stress and endometriosis. \nHuman Reproduction. \n2005; 20(7):2014-2020\n[13] Capobianco A, Cottone L, Monno A, \nManfredi AA, Rovere-Querini P . The \nperitoneum: Healing, immunity , and \ndiseases. The Journal of Pathology . \n2017; 243(2):137-147\n[14] Guo S- W , Ding D, Shen M, \nLiu X. Dating endometriotic ovarian \ncysts based on the content of cyst \nfluid and its potential clinical \nimplications. Reproductive Sciences. \n2015; 22(7):873-883\n[15] Ali O, Amso NN. Endometriosis: \nClinical manifestation and differential \ndiagnosis. In: Endometriosis. Taylor & \nFrancis, CRC Press; 2022. pp.  7-26\n\nA Comprehensive Overview of Endometriosis\n10\n[16] Coutureau J, Mandoul C, \nV erheyden C, Millet I, Taourel P . \nAcute abdominal pain in women of \nreproductive age: Keys to suggest a \ncomplication of endometriosis. Insights \nInto Imaging. 2023;14 (1):94\n[17] Hudelist G, Fritzer N, Thomas A, \nNiehues C, Oppelt P , Haas D, et  al. \nDiagnostic delay for endometriosis \nin Austria and Germany: Causes \nand possible consequences. Human \nReproduction. 2012;27(12):3412-3416\n[18] Andres MP , Arcoverde FV , Souza CC, \nFernandes LFC, Abrao MS, Kho RM. \nExtrapelvic endometriosis: A systematic \nreview . Journal of Minimally Invasive \nGynecology . 2020;27(2):373-389\n[19] Cromeens MG, Carey ET , \nRobinson WR, Knafl K, Thoyre S. \nTiming, delays and pathways to diagnosis \nof endometriosis: A scoping review \nprotocol. BMJ Open. 2021;11(6):e049390\n[20] Mahini SM, Y ounesi M, Mortazavi G, \nSamare-Najaf M, Azadbakht MK, \nJamali N. Non-invasive diagnosis of \nendometriosis: Immunologic and \ngenetic markers. Clinica Chimica Acta. \n2023; 538:70-86\n[21] Samare-Najaf M, Razavinasab SA, \nSamareh A, Jamali N. Omics-based \nnovel strategies in the diagnosis of \nendometriosis. Critical Reviews \nin Clinical Laboratory Sciences. \n2024; 61(3):205-225\n[22] Lukac S, Schmid M, Pfister K, \nJanni W , Schäffler H, Dayan D. \nExtragenital endometriosis in \nthe differential diagnosis of \nnon-gynecological diseases. \nDeutsches Ärzteblatt International. \n2022; 119(20):361\n[23] Holland T , Y azbek J, Cutner A, \nSaridogan E, Hoo W , Jurkovic D. V alue \nof transvaginal ultrasound in assessing \nseverity of pelvic endometriosis. \nUltrasound in Obstetrics and \nGynecology . 2010;36 (2):241-248\n[24] Zanardi R, Del Frate C, Zuiani C, \nBazzocchi M. Staging of pelvic \nendometriosis based on MRI findings \nversus laparoscopic classification \naccording to the American Fertility \nSociety . Abdominal Imaging. \n2003; 28:733-742\n[25] Gerges B, Lu C, Reid S, Chou D, \nChang T , Condous G. Sonographic \nevaluation of immobility of normal and \nendometriotic ovary in detection of deep \nendometriosis. Ultrasound in Obstetrics \n& Gynecology . 2017;49 (6):793-798\n[26] Guerriero S, Ajossa S, Garau N, \nAlcazar JL, Mais V , Melis GB. Diagnosis \nof pelvic adhesions in patients with \nendometrioma: The role of transvaginal \nultrasonography . Fertility and Sterility . \n2010; 94(2):742-746\n[27] Ichikawa M, Akira S, Kaseki H, \nWatanabe K, Ono S, Takeshita T . \nAccuracy and clinical value of \nan adhesion scoring system: A \npreoperative diagnostic method using \ntransvaginal ultrasonography for \nendometriotic adhesion. Journal of \nObstetrics and Gynaecology Research. \n2020; 46 (3):466-478\n[28] Wilde R, Alvarez J, Brölmann H, \nCampo R, Cheong Y , Lundorff P , \net  al. Adhesions and endometriosis: \nChallenges in subfertility management. \nArchives of Gynecology and Obstetrics. \n2016; 2(294):299-301\n[29] Remorgida V , Ferrero S, \nFulcheri E, Ragni N, Martin DC. \nBowel endometriosis: Presentation, \ndiagnosis, and treatment. \nObstetrical & Gynecological Survey . \n2007; 62(7):461-470\n\nDecoding Endometriosis: A Comprehensive Guide to Understanding Symptoms and Impacts\nDOI: http://dx.doi.org/10.5772/intechopen.1008252\n11\n[30] Audebert A, Petousis S, Margioula-\nSiarkou C, Ravanos K, Prapas N, \nPrapas Y . Anatomic distribution of \nendometriosis: A reappraisal based \non series of 1101 patients. European \nJournal of Obstetrics & Gynecology and \nReproductive Biology . 2018;230:36-40\n[31] Chapron C, Chopin N, Borghese B, \nFoulot H, Dousset B, V acher-\nLavenu MC, et  al. Deeply infiltrating \nendometriosis: Pathogenetic implications \nof the anatomical distribution. Human \nReproduction. 2006;21(7):1839-1845\n[32] Ferrero S, Moioli M, Dodero D,  \nBarra F . Symptoms of bowel \nendometriosis. In: Clinical Management \nof Bowel Endometriosis: From Diagnosis \nto Treatment. Cham: Springer; 2020. \npp. 33-39 \n[33] Abrao MS, Petraglia F , Falcone T , \nKeckstein J, Osuga Y , Chapron C. \nDeep endometriosis infiltrating \nthe recto-sigmoid: Critical factors \nto consider before management. \nHuman Reproduction Update. \n2015; 21(3):329-339\n[34] Roman H, Ness J, Suciu N, \nBridoux V , Gourcerol G, Leroi AM, \net  al. Are digestive symptoms in women \npresenting with pelvic endometriosis \nspecific to lesion localizations? A \npreliminary prospective study . Human \nReproduction. 2012;27(12):3440-3449\n[35] Maroun P , Cooper MJ, Reid GD, \nKeirse MJ. Relevance of gastrointestinal \nsymptoms in endometriosis. Australian \nand New Zealand Journal of Obstetrics \nand Gynaecology . 2009;49 (4):411-414\n[36] Arata R, Takakura Y , Ikeda S, \nItamoto T . A case of ileus caused by \nileal endometriosis with lymph node \ninvolvement. International Journal of \nSurgery Case Reports. 2019;54 :90-94\n[37] Marques-Ruiz A, Camara-Baena S, \nSanchez-Ramos Y . A new reported case \nof ileocecal infiltrative endometriosis, \na disease which is probably \nunderdiagnosed. Revista Espanola de \nEnfermadades Digestivas (REED). \n2018; 110(12):835-837\n[38] Guerra V eloz MF , Gómez \nRodríguez BJ, Benallal DC. Ileocecal \nendometriosis as an infrequent cause \nof intussusception. Revista Espanola de \nEnfermedades Digestivas: Organo Oficial \nde la Sociedad Espanola de Patologia \nDigestiva. 2018;110 (2):129-129\n[39] Rodriguez-Lopez M, Bailon-\nCuadrado M, Tejero-Pintor F , \nChoolani E, Fernandez-Perez G, Tapia-\nHerrero A. Ileocecal intussusception \nextending to left colon due to \nendometriosis. The Annals of The \nRoyal College of Surgeons of England. \n2018; 100(3):e62-e63\n[40] James O, Williams GL. Prolapsing \nmass in the caecum: Learning point for \nthe colonoscopist. BMJ Case Reports. \n2019;12 (4):1-2\n[41] Beamish RE, Aslam R, Gilbert JM. \nPostpartum caecal perforation due to \nendometriosis. JRSM Short Reports. \n2010; 1(7):1-3\n[42] Nishikawa A, Kondoh E, \nHamanishi J, Y amaguchi K, Ueda A, \nSato Y , et  al. Ileal perforation and \nmassive intestinal haemorrhage from \nendometriosis in pregnancy: Case \nreport and literature review . European \nJournal of Obstetrics & Gynecology and \nReproductive Biology . 2013;170 (1):20-24\n[43] Mabrouk M, Raimondo D, \nMastronardi M, Raimondo I, Del \nForno S, Arena A, et  al. Endometriosis \nof the appendix: When to predict and \nhow to manage—A multivariate analysis \nof 1935 endometriosis cases. Journal \n\nA Comprehensive Overview of Endometriosis\n12\nof Minimally Invasive Gynecology . \n2020; 27(1):100-106\n[44] Moulder JK, Siedhoff MT , \nMelvin KL, Jarvis EG, Hobbs KA, \nGarrett J. Risk of appendiceal \nendometriosis among women with deep-\ninfiltrating endometriosis. International \nJournal of Gynecology & Obstetrics. \n2017; 139(2):149-154\n[45] John BS, Snider A, Kellermier H, \nMinhas S, Nottingham J. Endometriosis \nof the appendix presenting as acute \nappendicitis with unusual appearance. \nInternational Journal of Surgery Case \nReports. 2018;53 :211-213\n[46] Akbulut S, Dursun P , Kocbiyik A, \nHarman A, Sevmis S. Appendiceal \nendometriosis presenting as perforated \nappendicitis: Report of a case and review \nof the literature. Archives of Gynecology \nand Obstetrics. 2009;280 :495-497\n[47] Dickson-Lowe RA, Ibrahim S, \nMunthali L, Hasan F . Intussusception of \nthe vermiform appendix. Case Reports. \n2015; 2015:bcr2014207584\n[48] Leonardi M, Espada M, Kho RM, \nMagrina JF , Millischer A-E, Savelli L, \net  al. Endometriosis and the urinary \ntract: From diagnosis to surgical \ntreatment. Diagnostics. 2020;10 (10):771\n[49] Charatsi D, Koukoura O, Ntavela IG, \nChintziou F , Gkorila G, Tsagkoulis M, \net  al. Gastrointestinal and urinary \ntract endometriosis: A review on the \ncommonest locations of extrapelvic \nendometriosis. Advances in Medicine. \n2018; 2018(1):3461209\n[50] Bretón SA, Carrasco AL, \nGutiérrez AH, González RR, de \nSantiago García J. Complete loss of \nunilateral renal function secondary to \nendometriosis: A report of three cases. \nEuropean Journal of Obstetrics & \nGynecology and Reproductive Biology . \n2013;171 (1):132-137\n[51] Cavaco-Gomes J, Martinho M, \nGilabert-Aguilar J, Gilabert-Estélles J. \nLaparoscopic management of ureteral \nendometriosis: A systematic review . \nEuropean Journal of Obstetrics & \nGynecology and Reproductive Biology . \n2017; 210:94-101\n[52] Leone Roberti Maggiore U, \nFerrero S, Salvatore S. Urinary \nincontinence and bladder \nendometriosis: Conservative \nmanagement. International \nUrogynecology Journal. \n2015; 26:159-162\n[53] Joseph J, Sahn SA. Thoracic \nendometriosis syndrome: New \nobservations from an analysis of 110 \ncases. The American Journal of Medicine. \n1996;100 (2):164-170\n[54] Rousset P , Gregory J, Rousset-\nJablonski C, Hugon-Rodin J, Regnard \nJ-F , Chapron C, et  al. MR diagnosis of \ndiaphragmatic endometriosis. European \nRadiology . 2016;26 :3968-3977\n[55] Korom S, Canyurt H, Missbach A, \nSchneiter D, Kurrer MO, Haller U, et  al. \nCatamenial pneumothorax revisited: \nClinical approach and systematic \nreview of the literature. The Journal of \nThoracic and Cardiovascular Surgery . \n2004; 128(4):502-508\n[56] Tulandi T , Sirois C, Sabban H, \nCohen A, Murji A, Singh SS, et  al. \nRelationship between catamenial \npneumothorax or non-catamenial \npneumothorax and endometriosis. \nJournal of Minimally Invasive \nGynecology . 2018;25 (3):480-483\n[57] Danielpour PJ, Layke JC, Durie N, \nGlickman LT . Scar endometriosis—A \nrare cause for a painful scar: A case \n\nDecoding Endometriosis: A Comprehensive Guide to Understanding Symptoms and Impacts\nDOI: http://dx.doi.org/10.5772/intechopen.1008252\n13\nreport and review of the literature. \nCanadian Journal of Plastic Surgery . \n2010; 18(1):19-20\n[58] Siquara De Sousa AC, Capek S, \nAmrami KK, Spinner RJ. Neural \ninvolvement in endometriosis: Review of \nanatomic distribution and mechanisms. \nClinical Anatomy . 2015;28 (8):1029-1038\n[59] Niro J, Fournier M, Oberlin C, \nLe Tohic A, Panel P . Endometriotic \nlesions of the lower troncular nerves. \nGynécologie, Obstétrique & Fertilité. \n2014; 42(10):702-705\n\n\n\n15\nChapter 2\nEndometriosis-Associated Ovarian \nCarcinoma\nIoana Pavaleanu, Teodora Ana Balan, \nTiberiu Nicolae Poparlan, Ana Maria Haliciu, \nTudor Andrei Butureanu, Ana Maria Apetrei, Razvan Socolov , \nAndreea Ioana Pruteanu and Raluca Anca Balan\nAbstract\nThe link between endometriosis and ovarian carcinoma has been recognized early \non, initially termed endometriosis-associated ovarian carcinoma and subsequently \nreferred to as endometriosis-associated ovarian carcinoma (EAOC). The relationship \nbetween endometriosis and cancer is well supported by epidemiological evidence, \nhighlighting common risk factors. Two potential mechanisms have been proposed: \none involving the direct malignant transformation of endometriotic lesions, and the \nother suggesting a shared origin in precursor mechanisms or risk factors, followed \nby distinct molecular pathways. This chapter explores the epidemiological links, \nmolecular mechanisms, and clinical implications of endometriosis-associated ovarian \ncarcinoma, highlighting its distinct subtypes and risk factors.\nKeywords: endometriosis, endometriosis-associated ovarian carcinoma, \nendometriosis-related ovarian neoplasm, ovarian malignancy , malignant \ntransformation\n1. Introduction\nEndometriosis is a gynecological entity characterized by the presence of ectopic \nendometrium outside the uterus, in a multitude of locations, mainly in ovary (67%), \nfollowed by anterior and posterior cul de sac, uterosacral ligaments, posterior broad \nligaments, fallopian tubes, round ligaments, and sigmoid colon or appendix [1]. \nOther less frequent locations are bladder and cervix, and more rarely skin, regional \nlymph nodes, or lung.\nThe importance of the disease is given by its relatively high prevalence in women \nof reproductive age, its frequent association with infertility and with chronic pain, \nand its subsequent negative impact on the quality of life. Although many hypotheses \nhave been postulated regarding the etiopathogenesis of endometriosis, its exact \nmechanisms remain unclear. Endometriosis is essentially a benign condition, but \nthere are some common characteristics that suggest a connection to ovarian cancer, \nmaking the pathogenic pathways even more intriguing.\n\nA Comprehensive Overview of Endometriosis\n16\nOne element that supports the correlation between the two clinical entities is the \nfact that they share some epidemiological characteristics. These include the common \nrisk factors, such as early onset of menstruation, short menstrual cycles, nulliparity , \nand late menopause, alongside the protective factors like oral contraceptive use, mul-\ntiparity , tubal ligation, and hysterectomy [2]. Two primary mechanisms are hypoth-\nesized for this correlation: the direct malignant transformation of the endometriotic \nlesions or a combination of shared precursor mechanisms and risk factors, leading to \ndistinct molecular pathways [3, 4].\nThe linkage between endometriosis and ovarian cancer was initially recognized \nunder the term “endometriosis-associated ovarian carcinoma” (EAOC) [5] and \nsubsequently referred to as “endometriosis-related ovarian neoplasm” (ERON) [6, 7] \nor “endometriosis-associated ovarian carcinoma” [8, 9], predominantly manifesting \nas endometrioid carcinoma, clear-cell carcinoma, seromucinous borderline tumors, \nMüllerian adenosarcoma, and endometrioid stromal sarcoma.\nNotably , a majority of these tumors (70%) develop within the first decade follow -\ning an endometriosis diagnosis, with 60% of cases exhibiting an intermediary stage \nof atypical endometriosis [9].\nFurthermore, given the inherent invasive and metastatic abilities of endometrio-\nsis, its behavior closely resembles that of malignant conditions [10]. This profound \nconnection has prompted investigations into potentially shared molecular pathways \nand the involvement of key molecules in their pathogenesis, thereby facilitating the \nassessment of endometriosis etiopathogenetic theories.\nRegarding these molecular pathogenic pathways, a multitude of molecules have \nbeen studied in both endometriosis and EAOC. In this regard, estrogen is acknowl-\nedged as a promoter of ovarian cell proliferation, enhancing the mobility of malig -\nnant cells and inhibiting intercellular adhesion [11, 12]. The mediation by estrogen \nand progesterone receptors in the actions of steroid hormones on both endometriosis \nand endometrioid EAOC has been established, and recent studies have also correlated \nthe expression of these receptors with clinical outcomes in ovarian cancer [12, 13]. \nFurthermore, p53 alterations also represent a significant molecular event in the \ntransformation of endometriosis into carcinomas [14]. Similarly , Ki-67 expression, \nwhich is closely associated with cell proliferation, is employed to evaluate the growth \nof various neoplastic lesions, including both endometriosis and EAOC [15].\n2. EAOC risk factors\nEndometriosis is a condition relatively often associated with various types of \nneoplasms. EAOC occurs in 5–10% of endometriosis cases, and an intermediate \nstage of atypical endometriosis can be detected in 0.7–1.6% of cases [16]. A recent \nmeta-analysis of 24 observational studies evaluated the link between endometriosis \nand ovarian cancer, revealing a calculated summary relative risk of 1.93 for ovarian \ncancer in women diagnosed with endometriosis compared to those without the \ncondition [17].\nIn order to assess the individual risk for EAOC among endometriosis patients, \nThomsen et  al. have shown that in a group of women over the age of 45 years with \nendometriosis, factors, such as nulliparity , postmenopausal status, larger endome-\ntriomas (>9 cm), and either endogenous or exogenous hyperestrogenism, along \nwith the presence of cysts containing solid components, were identified as risk \nindicators for EAOC [18].\n\n17\nEndometriosis-Associated Ovarian Carcinoma\nDOI: http://dx.doi.org/10.5772/intechopen.1007677\nRegarding the risk for a specific histological type of EAOC, a recent study has \nutilized genetic markers as proxies for epithelial ovarian cancer. The analysis revealed \na significant correlation between these entities, with an odds ratio (OR) of 1.23. More \ndetailed analysis, investigating for specific ovarian cancer histotypes possibly linked \nto endometriosis, showed an association of endometriosis with the risk of endometri-\noid carcinoma, clear-cell carcinoma, and low malignant potential tumors [19].\nSome researchers have hypothesized the influence of the microenvironment, \nspecifically the high iron concentration in the walls of endometriotic cysts in cases \nwith prolonged evolution, through the persistence of oxidative stress induced by iron, \nresulting in subsequent DNA damage and numerous genetic mutations, such as PTEN \n(phosphatase and tensin homolog), ARID1 (AT -rich interactive domain-containing \nprotein 1), PIK3CA (phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit \nalpha), and loss of heterozygosity [16].\nOncogenic mutations of the β-catenin phosphorylation site (catenin beta 1 \n(CTNNB1)) lead to the formation of a stable protein, detected both in endometriosis \nand in EAOC associated with endometriosis [16].\nA significant role in the pathogenesis of endometriosis should be attributed to \npolygenic susceptibility , which implies a metabolic, endocrine, and immune association \nresponsible for decreased immune surveillance, alongside pelvic inflammation [20–22].\nAdditionally , progressive accumulations of genetic alterations in tumor suppres-\nsor genes and oncogenes are likely responsible for the development of endometriosis \nand its possible association with the development of malignant conditions [23–29]. \nPremalignant lesions (atypical endometriosis) are characterized by multiple muta -\ntions in tumor suppressor genes, oncogenes, cell adhesion molecule (CAM), as well as \nloss of heterozygosity (LOH) and inflammatory immunomodulation [30].\n3.  Pathogeny/molecular mechanisms involved in the development of \nendometriosis and EAOC\nV arious endometriosis pathogenic pathways make this condition very similar to \nneoplastic processes. Among the widest spread and accepted pathogenetic theories in \nendometriosis are retrograde menstruation, immune dysregulation, coelomic meta -\nplasia, hematogenous or lymphatic spread, endometrial stem cell recruitment theory, \nbone marrow-derived stem cells, alteration in epigenetic regulation, hormonal imbal-\nance, and microRNAs (miRNAs). Besides these theories, the carcinogenetic pathways \nand external environmental factors are also believed to have a significant impact on \nendometriosis behavior and outcome [31, 32]. Although first proposed in the late \nnineteenth century , the most recently introduced hypothesis is the embryogenetic \ntheory with Müllerian remnants’ induction [32]. This is considered a type of metapla -\nsia theory [31], stipulating that remnants of embryonic cells of Müllerian or W olffian \nduct may transform into endometriotic lesions [31], by spreading the primordial \nendometrial cells towards the posterior pelvic floor during embryogenesis [32]. Most \nclinicians and theoreticians agree upon the menstrual reflux theory , which implies \nthat endometrial cells are being expelled during menstruation, via the fallopian tubes, \ninto the peritoneal cavity . Here, under yet unknown influences, these cells gain the \ncapacity of adhesion to the peritoneal surface, invasion of the peritoneal lining, and \nfurther cellular survival and division. Their ectopic surviving capacity is provided by \na mechanism of escaping the immune supervision of these newly formed implants. \nFurthermore, these implants have the capacity of neoangiogenesis, which promotes \n\nA Comprehensive Overview of Endometriosis\n18\ngrowth and development by providing nutrients and growth factors to the already-\nestablished implants.\nAlthough a key role is attributed to the reflux of stem cells into the peritoneal \ncavity , the microenvironmental factors that stimulate stem cell functions and allow \nthe development of endometriotic implants are very important as adjuvants to the \nmechanism of retrograde menstruation. Relatively recent data have demonstrated \nthe existence of mesenchymal stem cells and endometrial progenitor cells in \nendometriosis and their potential evolution towards differentiation into nine cell \nlines, as follows: adipocytic, osteogenic, cardiomyocytic, respiratory epithelial, \nneurocytic, myocytic, endothelial, pancreatic, and hepatic [33]. Considering the \nwidespread distribution of endometriosis in the human body , modern theories \nattempt to combine the effect of multiple factors contributing to its development, \nas multifactorial, multi-compartmental pathogenic phenomena, associated with \nepiphenomena, such as estrogen dependence [34], genetic susceptibility [35], and \nthe possibility of direct spread through “transplantation” [34]. These processes add \nto the immune system’ s inability to neutralize ectopic endometrial cells [36–39], \nenvironmental factors, and the coexistence of congenital defects, such as hymenal \natresia, for example. Last but not least, the most plausible pathogenic mecha -\nnism involves stem cells as the main factors responsible for the process of ectopic \nimplantation via retrograde menstruation. The evasion of immune clearance, as \nthe first step in the development of endometriotic lesions, is supported by various \nstudies suggesting a modification of the immune system. Endometriosis may be \nassociated with autoimmune diseases (systemic lupus erythematosus, rheumatoid \narthritis, Sjögren’ s syndrome, autoimmune thyroiditis, and multiple sclerosis) or \natopic diseases (allergies, asthma, and eczema) [40]. Considering that multiple \nautoantibodies can be identified in endometriosis [41], it may be considered that \nthis autoimmune reactivity could be a consequence of chronic inflammation. In the \nlast decade, studies have identified genetic, angiogenetic [42], endocrine, meta -\nbolic, and immunological anomalies, such that the pathogenesis of endometriosis is \nmultifactorial, multi-compartmental, and associated with epiphenomena, many of \nwhich represent, in fact, consequences of the primary lesion.\nNeoplastic transformation of some of these endometriotic implants has been a \nsubject of research and debate. Nearly a century ago, John A. Sampson first identi-\nfied ectopic endometrium-like tissue as a potential cause of ovarian carcinoma. \nHe proposed that “metastatic or embolic endometriosis results from the menstrual \ndissemination of endometrial tissue into the venous circulation” [43]. This idea of \nretrograde menstruation leading to the implantation of endometrial cells in the \nperitoneal cavity , eventually transforming into ovarian cancer through atypical endo-\nmetriosis, has since been widely studied. It seems that the ovarian microenvironment \nplays specific role in this malignant transformation [44], as it is an essential condition \nof such neoplasia. Even though endometriosis might have other locations, except the \novary , these sites are almost never the site of a malignant transformation [44, 45]. For \nexample, the literature provides reports of only a few cases of carcinomas arising in \nrectovaginal endometriosis [46, 47].\nRegarding the intermediate steps between endometriosis and EAOC, Kurman \net  al. [48] proposed the eutopic endometrium as the precursor site of origin of EAOC, \nendometriosis as the potential precursor lesion, and atypical endometriosis as the \nimmediate precursor lesion. In the same context, Karnezis et  al. consider endometrio-\nsis as the tissue of origin of EAOC, endometrial epithelial cells as the cells of origin, \nand endometrioid borderline tumors as the precursor lesion [49]. They also propose \n\n19\nEndometriosis-Associated Ovarian Carcinoma\nDOI: http://dx.doi.org/10.5772/intechopen.1007677\na classification of endometriosis as “high risk” and “low risk” depending on the pres-\nence of atypical endometriosis.\nThe molecular features of EAOC have been intensely studied in the last few years, \nand the results lead to different conclusions, depending on the type of EAOC. In this \nregard, endometriosis is considered a precursor to two completely different histo-\nlogical entities, endometriosis-associated ovarian clear-cell carcinoma (OCCC) and \nendometriosis-associated ovarian endometrioid carcinoma, without any recurrent \ngenetic mutation that is unique to either of them [50].\n3.1 Genetic mutations\nSeveral genetic mutations have been identified as key drivers in the malignant \ntransformation of endometriosis and the development of endometriosis-associated \novarian cancer (EAOC). Common mutations include those in p53, K-ras (Kirsten rat \nsarcoma virus), ARID1A, PIK3CA, and PPP2R1A (serine/threonine-protein phospha -\ntase 2A regulatory subunit A). Although breast cancer (BRCA) mutations are preva -\nlent in ovarian carcinomas, they are less frequently associated with EAOC [51].\nMutations in the ARID1A gene, which encodes the BAF250a (BRG-associated \nfactor 250a) protein—a critical component of the switch/sucrose non-fermentable \n(SWI/SNF) adenosine triphosphate (ATP)-dependent chromatin remodeling com-\nplex—are found in nearly half of clear-cell and endometrioid carcinomas [52]. Loss \nof BAF250a in EAOC tissues is associated with increased expression of gamma H2A \nhistone family member (γH2AX), a marker for DNA damage response, of the pro-\napoptotic regulators, such as B-cell lymphoma 2-interacting mediator (BIM) and \nBcl-2-associated X-protein (BAX), and decreased expression of the anti-apoptotic \ngene B-cell lymphoma 2 (Bcl-2). These findings suggest that chromatin remodeling \nand DNA damage response pathways may be involved in the early stages of precancer -\nous lesions. ARID1A also shares downstream targets with p53, and its loss can lead to \nthe dysregulation of p53-controlled genes [53].\nIn clear-cell EAOC, somatic mutations in the PIK3CA gene, which encodes a \ncatalytic subunit of phosphatidylinositol-3 kinases (PI3K), often occur early and \nfrequently coincide with the loss of ARID1A protein expression, potentially having \nsynergistic effects [54]. Additional early markers in ARID1A-deficient carcinomas \ninclude the activation of RAC-alpha serine/threonine-protein kinase (AKT) through \nincreased AKT serine/threonine kinase 1 (AKT1) expression and phosphorylation \n(phosphorylated AKT (pAKT)). Moreover, differential expression of components in \nthe mammalian target of rapamycin (mTOR) pathway appears to link endometriosis \nwith ovarian cancer development [53].\nA less frequent mutation found in approximately 16–19% of EOAC and ovarian \nclear-cell carcinoma (OCCC) cases affects the oncogene PPP2R1A (serine/threonine-\nprotein phosphatase 2A 65 kDa regulatory subunit A alpha isoform), which encodes a \nregulatory subunit of serine/threonine phosphatase 2 (PP2A), a negative regulator of \ncell growth [55].\nOverall, the PI3K/protein kinase B (AKT)/mTOR pathway plays a critical role in \ncell cycle regulation, and mutations that alter gene regulation within this pathway \ncontribute to the development and progression of ovarian cancer, as well as the \ntransformation of healthy endometrial tissue into endometriosis and EAOC [56]. In \ncontrast, the activity of the phosphatase and tensin homolog (PTEN), which coun-\nteracts the PI3K/AKT pathway , is diminished due to PTEN silencing in EAOC, thus \nreducing PTEN’ s inhibitory effect on cell growth and division [57].\n\nA Comprehensive Overview of Endometriosis\n20\nEr et  al. identified additional mutated genes in the Wnt pathway , the MAPK/ERK \n(mitogen-activated protein kinase/extracellular signal-regulated kinase 1/2) pathway , \nthe Notch signaling pathway , cell cycle regulation, and the mismatch repair system \nthrough targeted next-generation sequencing [58]. Notably , the Notch signaling path-\nway is also disrupted in endometriosis and has been implicated in its pathogenesis [53].\n3.2 Epigenetic mechanisms\nBeyond genetic mutations, epigenetic mechanisms also play a crucial role in the \nmalignant transformation of endometriosis into EAOC. For example, promoter \nhypermethylation can lead to the transcriptional inactivation of the MutL protein \nhomolog 1 (MLH1) gene, which encodes a DNA mismatch repair (MMR) protein. \nThis inactivation results in microsatellite instability and the accumulation of \nspontaneous mutations, thereby advancing the progression towards EAOC [59]. \nAdditionally , other differentially methylated genes, such as Ras association domain \nfamily member 2 (RASSF2), which encodes the Kirsten rat sarcoma viral oncogene \nhomolog (KRAS)- specific effector protein Ras association domain-containing pro-\ntein 2, and Runt-related transcription factor 3 (RUNX3), which encodes the tumor- \nsuppressing Runt-related transcription factor 3, have been identified as potential \ncontributors to this malignant transformation [60].\n3.3 The tumor microenvironment\nThe tumor microenvironment is crucial in shaping EAOCs, with estrogen concen-\ntration being a significant factor. High estrogen levels, whether from external sources \nlike hormone replacement therapy or produced endogenously by the ovaries, promote \nthe proliferation of endometriotic cells. Estrogen signaling in EAOC is complex and \ninfluenced by factors, such as nutritional status, oxidative stress, and surrounding \ncells, which in turn affect cellular metabolism, epithelial-to-mesenchymal transition \n(EMT), angiogenesis, and invasiveness [53].\nmicroRNAs (miRNAs) are emerging as important posttranscriptional regulators \nof gene expression and potential biomarkers in endometriosis and EAOC. These small \nnon-coding RNA (ncRNA) molecules can silence genes by binding to complementary \nsequences in messenger RNA (mRNA), leading to RNA degradation or translational \nrepression. Dysregulation of miRNAs, such as those in the microRNA-200 (miR-200) \nand lethal-7 (let-7) families, has been observed in ovarian cancer and is involved \nin processes like the epithelial-to-mesenchymal transition and tumor progression \n[53]. Of note, microRNA-200b (miR-200b) also plays a role in the development of \nendometriosis, targeting zinc finger E-box-binding homeobox 1 (ZEB1), zinc finger \nE-box-binding homeobox 2 (ZEB2), and Kruppel-like factor 4 (KLF4), in order to \nregulate the stem cell phenotype, the proliferation, invasiveness, and the growth of \ninvasive protrusions of endometriotic cells [61].\nSzubert et  al. found that the expression levels of microRNA-31-3p (miR-31-3p) and \nmiR-200b were reduced in cancerous lesions compared to normal ovarian tissue and \nendometriosis tissue [62]. microRNA 31 (miR-31) activates hypoxia-inducible factor \n(HIF) under normoxic conditions by targeting the 3′  untranslated region (3′  UTR) of \nfactor-inhibiting hypoxia-inducible factor (HIF), which leads to increased produc -\ntion of vascular endothelial growth factor (VEGF). VEGF overexpression is linked \nto both endometriosis and the progression to EAOC [53]. Furthermore, reduced \nlevels of other microRNAs, including microRNA-17-5p (miR-17-5p), microRNA 20a \n\n21\nEndometriosis-Associated Ovarian Carcinoma\nDOI: http://dx.doi.org/10.5772/intechopen.1007677\n(miR-20a), microRNA 222 (miR-222), and microRNA 125a (miR-125a), have been \nassociated with angiogenesis in endometriosis by regulating factors, such as Runt-\nrelated transcription factor 1 (RUNX1), connective tissue growth factor (CTGF), \nthrombospondin-1 (TSP-1), and vascular endothelial growth factor-A (VEGF-A) [53].\nOxidative stress is another key factor in the malignant transformation of endome-\ntriosis to EAOC. microRNAs regulate oxidative stress by controlling the expression \nof reactive oxygen species (ROS)-related enzymes. Persistent oxidative stress in \nendometriotic cysts, possibly due to the release of free iron during menstruation, may \ncontribute to their carcinogenic transformation [53].\nInflammation plays a significant role in EAOC carcinogenesis by creating a pro-\ntumorigenic environment that promotes DNA damage, tissue remodeling, immune \nsuppression, and angiogenesis. Several inflammatory cytokines, complement factors, \nand inflammasome-related genes have been identified as contributors to the develop-\nment of EAOC [53].\nThe tumor’ s ability to adapt to local nutrient availability through metabolic \nreprogramming is another emerging hallmark of cancer. Endometriotic cells often \nprefer aerobic glycolysis to generate energy , even in the presence of oxygen, which \nhelps them survive in the extrauterine environment. Ovarian cancer cells exhibit \nmetabolic heterogeneity and flexibility , allowing cancer cells to adapt to varying \nlevels of glucose, lipids, and amino acids, thus contributing to their proliferation and \nsurvival [53].\nIt is considered that 2% of ovarian endometriotic lesions will undergo malignant \ntransformation [63]. The exact etiopathology remains unclear, but both intrinsic \nfactors within the endometrial tissue and microenvironmental factors are considered \ncontributors to its survival in the peritoneum and potential malignant transformation  \n[64]. For example, the increased frequency of chromosomal abnormalities in ovarian \nendometriosis, as opposed to extragonadal endometriosis, suggests that the ovarian \nstromal environment may play a role in initiating genetic alterations, possibly leading \nto invasive cancer [53].\nIn summary , the genetic profiles of benign ovaries and ovarian endometriosis \ndiffer significantly from those of EAOC and ovarian cancer [65].\nThe endometriosis-associated ovarian clear-cell carcinoma harbors mutations \nin ARID1A, PIK3CA, CTNNB1, and PTEN, while endometriosis-associated ovarian \nendometrioid carcinoma harbors mutations in PTEN, CTNNB1, KRAS, ARID1A, \nPPP2R1A, and PIK3CA [50].\nInactivating ARID1A mutations are the most common molecular genetic altera -\ntions reported in EAOC [66], resulting in loss of expression of the protein encoded \nby ARID1A (BAF250a). When expressed, this protein normally suppresses cellular \nproliferation through a p53-dependent transcription regulation of several tumor sup-\npressors including CDKN1A (cyclin-dependent kinase inhibitor 1A) (encoding p21) \nand SMAD3 (mothers against decapentaplegic homolog 3) [67].\n4.  Pathological characteristics of ovarian endometriosis, atypical \nendometriosis, and EAOC\n4.1 Endometriosis\nOn gross examination, endometriomas or ovarian endometriotic cysts present fibrotic \nwalls, with smooth lining and characteristic dark brown content (chocolate cyst) [68].  \n\nA Comprehensive Overview of Endometriosis\n22\nIf endometriosis has a polypoid aspect, it leads to the differential diagnosis of a neoplasm \nboth on grossing and frozen sections [69]. Sometimes, the cyst can display red-brown or \nwhite plaques, with a gelatinous consistency [70, 71].\nFor the histopathological diagnosis of endometriosis, at least two of three criteria \nare needed: endometrial-type glands, lined by Müllerian-type epithelium, some-\ntimes with degenerative atypia (enlarged faded nuclei) or metaplasia, included in an \nendometrial-type stroma. Sometimes, smooth muscle metaplasia, osseous metaplasia, \ndecidual change, or myxoid aspects are found [72, 73]. Another rare and particular \naspect is the presence of epithelial metaplastic changes or metaplasia in ovarian endo-\nmetriosis, which should not be considered neoplastic features. A study conducted \nby Fukunaga on 315 cases of ovarian endometriosis found 162 cases with metaplastic \nchanges, all of them being associated with atypical endometriosis or malignant ovar-\nian epithelial tumor. Although no significant relationship was identified between the \ntype of metaplasia in endometriosis and the type of carcinoma, mucinous metaplasia \nwas correlated with cases of Müllerian mucinous borderline tumors, and thus there \ncould be an association between this type of metaplasia and hyperplasia encountered \nin ovarian endometriosis and Müllerian mucinous borderline ovarian tumors [74].\nMoreover, there are cases when the histopathological diagnosis is made only on \nthe presence of endometrial stroma (stromal endometriosis) or indirectly , due to \nthe chronic hemorrhage, with foamy or hemosiderin-laden macrophages. Rarely , \nLiesegang rings, defined as eosinophilic noncellular rings embedded in necrotic tissue \nor necrotic pseudoxanthomatous nodules, with central necrosis bounded by histio-\ncytes and an outer fibrous tissue are encountered [72]. Somewhat similar morpho-\nlogical aspects as mentioned above, suggestive of endometriosis, define the so-called \n“burnt out endometriosis. ”\n4.2 Atypical endometriosis\nAtypical endometriosis was reported in 1.74.4% of endometriotic ovarian \ncysts, being considered as the precursor lesion for EAOC, mainly endometrioid or \nclear-cell type. Atypical endometriotic lesions were found in association with these \ntumors in 25% of cases, presenting the same genomic alterations as EAOC [75]. \nHistopathological landscape is characterized by crowded endometrial-type glands, \nwith complex architecture, lined by atypical epithelial cells as those observed in \natypical endometrial hyperplasia (AEH) [75–77].\nAtypical endometriosis (AE) has been historically described as having histological \ncharacteristics that are intermediary between benign and malignant states, including \nenlarged atypical hyperchromatic nuclei, an elevated nuclear-to-cytoplasm ratio, and cel -\nlular overcrowding, sometimes with hobnail features [75–79]. This type of lesion has been \nfound to sometimes coexist with endometriosis and more frequently with EAOC, and it \ninvolves changes in the epithelial lining of endometriotic cysts marked by varying levels \nof cellular stratification, disorganization, inflammation, and cytological atypia [8, 77].\nAE has been proposed as a precancerous lesion, as studies have shown that it can \nbe considered as a transitional state between endometriosis and EAOC. In this regard, \nOgawa et  al. have reevaluated microscopic slides from 127 patients with primary \novarian carcinoma and concluded that 37 patients also had endometriosis, from which \n29 cases had atypical endometriosis. The study reported the transition from typical \nendometriosis to AE in 22 cases, and the transition from AE to carcinoma in 23 cases, \nsuggesting an AE could be considered a precancerous lesion, even though it is not \nencountered in all cases [80].\n\n23\nEndometriosis-Associated Ovarian Carcinoma\nDOI: http://dx.doi.org/10.5772/intechopen.1007677\nIn order to further refine the risk of EAOC in the AE cases, Stamp et  al. suggested \nthat BAF250a expression may be a biomarker of cancer risk in patients diagnosed with \natypical endometriosis. In their study , which included 35 cases of EAOC and 8 cases of \nnon-cancerous AE, the immunohistochemical (IHC) expression of BAF250a was lost \nin most of the cases of AE associated with EAOC, but not in non-cancerous AE [81].\n4.3 Endometriosis-associated ovarian cancers\nThe main epithelial ovarian cancer histotypes are classified as types I and II, \naccording to the dualistic pathogenic model proposed by Kurman et  al. [48]. The first \ncategory comprises the so-called endometriosis-associated tumors and it includes the \nendometrioid, clear-cell, and seromucinous carcinomas. Type II tumors are mainly \ncomposed of high-grade serous carcinomas, which represent almost the majority \n(70%) of ovarian carcinomas [48]. Among the EAOC, the seromucinous histotype \nis rare, while the most frequent histotypes associated with endometriosis are the \nendometrioid ovarian carcinomas and the clear-cell ovarian carcinomas. One essen-\ntial difference between the two categories resides in their pathogenic models and their \nsubsequent prognosis.\nIt is now considered that most high-grade serous carcinomas originate from \nundetectable atypical lesions within the fallopian tubes [82], with subsequent exfolia -\ntion and implantation on the ovaries, peritoneum, omentum and on abdominopelvic \norgans, resulting in the development of late-stage cancers from inception. In contrast, \nmost of the type I tumors originate from ovarian endometriotic cysts that are easily \ndetected, and they are confined to the ovary for a variable period of time, making \ntherapeutic approaches more efficient and improving the prognosis [48].\nTo conclude, EAOC typically manifests as endometrioid and clear-cell carcinomas, \nand less frequently by seromucinous borderline tumors, squamous cell carcinoma, \ncarcinosarcoma, adenosarcoma, or endometrial stromal sarcoma.\n4.3.1 Endometrioid carcinomas\nEndometrioid carcinomas represent 25% of ovarian carcinomas [83]. Regardless of \nthe disease stage or response to platinum-based therapies, the prognosis is favorable. \nIt has been found that patients diagnosed with endometrioid ovarian carcinoma often \nhave a clinical history and microscopic foci of endometriosis (10–20%) [84]. Squamous \ndifferentiation, a pathognomonic element for ovarian endometrioid tumors, is found \nin about half of the cases associated with endometriosis. Morphologically , ovarian \nendometrioid carcinomas exhibit an endometrioid-like epithelium, similar to uterine \nendometrioid carcinomas, characterized by stratified columnar, non-mucinous, with a \nvilloglandular pattern. Most tumor glands present luminal margins, oriented back-to-\nback, separated by an abundant fibrocellular stroma. Ovarian endometrioid carcinoma \nexhibits the following architectural patterns: papillary , cribriform, glandular, micro-\nglandular, spindle cell, secretory , ciliated cell, sertoliform, and sex cord-like [85]. Based \non nuclear grade and the percentage of solid area, ovarian endometrioid carcinomas are \nclassified as: well, moderately , or poorly differentiated. If the well-differentiated type \npresents a villoglandular architecture, the moderately and poorly differentiated types are \nmost frequently solid, glandular, or microglandular. Cellular atypia and mitotic figures \nare rarely encountered in poorly differentiated carcinomas, while high-grade tumors \nexhibit marked nuclear pleomorphism, associated with an increased mitotic index. In \nthe situation of an undifferentiated pattern of ovarian carcinoma, the following criteria \n\nA Comprehensive Overview of Endometriosis\n24\nfavor a diagnosis of endometrioid carcinoma: (i) metaplastic structural elements, such \nas squamous, morular, mucinous, or “hobnail, ” (ii) cellular phenotype (eosinophilic cells \nor secretory changes), (iii) foci of endometriosis, and (iv) fibrous stroma [85].\n4.3.2 Clear-cell carcinomas\nClear-cell carcinomas represent approximately 5% of ovarian carcinomas [83]. The \ncharacteristic feature of these tumors is that, regardless of the grading type used, they \nhave an unfavorable progression, often recur compared to other histological types, \nand have a reduced response rate to chemotherapy (CHT) [84]. Thus, compared to \nother tumor types, although they are included in the category of type I tumors, these \nare high-grade, with a reserved prognosis. The latest trends according to the special -\nized literature suggest including ovarian clear-cell carcinomas in the category of type \nII tumors. The etiopathogenesis of this category is closely related to endometriosis, \nsimilar to ovarian endometrioid tumors. Morphologically , ovarian clear-cell carcino -\nmas have three essential features to be followed: (i) cytoplasmic changes, (ii) nuclear \nappearance, and (iii) architectural pattern. Due to the “clear” appearance of the \ncellular cytoplasm (resulting from the accumulation of glycogen) or the eosinophilic \nappearance (oxyphil cells), clear-cell carcinomas are easily recognized. It should be \nnoted that, for histopathologists, just the clear cytoplasmic appearance is not suf -\nficient for diagnosis, as this appearance can occur not only as a result of glycogen \naccumulation but also of lipids or as a result of cellular injury with a hydropic-\nvacuolar cytoplasmic appearance. The particular nuclear appearance gives the cell a \n“target” shape, “hobnail, ” characterized by hyperchromatic nuclei that protrude into \nthe glandular lumen. The most frequently encountered architectural phenotypes in \nclear-cell carcinomas are: tubulocystic/cystic (dilated cystic glands lined by flattened \nepithelium), papillary (small round papillary axes lined by epithelium with a maxi-\nmum of two layers of polygonal or cuboidal cells), and the solid pattern, with mucin-\ncontaining cytoplasm (rarely described). Characteristically , all described patterns are \nlocated in a hyalinized, eosinophilic, fibroblastic, myxoid, rarely colloid stroma. The \nincreased mitotic index, stratification, and cellular detachment are not characteristic \nof ovarian clear-cell carcinomas [86]. Occasionally , cellular features such as “signet \nring” cells can be identified [86]. Additionally , morphological features, such as open \ntumor rings, hyaline globules, and targetoid bodies, have been described [86].\n4.3.3 Borderline seromucinous tumors\nBorderline seromucinous tumors were historically designated as borderline \nMüllerian mucinous or borderline endocervical-type or mixed epithelial papillary \nborderline tumor of Müllerian type or atypical proliferative tumors, and these terms \nare not currently being used. They constitute a small proportion of ovarian mucinous \nborderline tumors (10–15%) [7 , 8] and are associated, in about one-third to half of \ncases, with endometriosis [8, 45]. Cytologically , these tumors exhibit a stratified epi-\nthelium containing a combination of endocervical-type mucosecretory cells, ciliated \ncells, and occasional acidophilic cells with abundant cytoplasm [7 , 45], alongside a \nwide range of possible differentiations (endometrioid, serous, clear cell, and squa -\nmous) [8], most commonly presenting a low degree of atypia [8]. These tumors are \noften bilateral [8], are associated with stromal microinvasion [8] and although most \nof them are detected at an early stage, some may present peritoneal implants, as in the \ncase of borderline serous tumors [7], and even lymph node involvement [45].\n\n25\nEndometriosis-Associated Ovarian Carcinoma\nDOI: http://dx.doi.org/10.5772/intechopen.1007677\nIn terms of potential pathogenic mechanisms, the hypothesis of a mucinous meta -\nplasia within endometriosis followed by progression to a cystadenoma and borderline \ntumor has been proposed [45].\nThis type of tumor shares the genetic profile of endometrioid tumor [8] and has a \nfavorable prognosis [7]. Rarely , the malignant character associated with the border-\nline nature is observed, suggestive of tumor progression and having negative implica -\ntions for the prognosis [8].\nDue to the low degree of diagnostic concordance among gynecological patholo-\ngists and the immunohistochemical pattern of low-grade endometrioid or serous \ntumors, this diagnostic category remains controversial, suggesting its classification as \na subtype of another type of ovarian tumor [8].\n4.3.4 Carcinosarcoma\nCarcinosarcoma, also known as malignant mixed Müllerian tumor or malignant \nmixed mesodermal tumor, morphologically represents a combination of malignant \nepithelial components, often high-grade (typically serous or endometrioid, and rarely \nundifferentiated) and mesenchymal components, either homologous or heterologous \n(such as osteosarcoma, rhabdomyosarcoma, chondrosarcoma, angiosarcoma, or lipo-\nsarcoma) [7 , 45]. These tumors frequently associate with serous tubal intraepithelial \ncarcinoma [8] and, in about 50% of cases, with endometriosis [7].\nPatients are most commonly over 50 years old, and the diagnosis is typically made \nin advanced stages [7]. Generally , the tumors are predominantly solid, large, with \nareas of cystic degeneration [45], and often exhibit extraovarian extension as they \nprogress [7]. According to recent studies on the immunohistochemical and molecular \nprofile, carcinosarcomas are included in the category of carcinomas that undergo \nstromal differentiation [8].\n4.3.5 Adenosarcoma\nAdenosarcoma is a neoplasm characterized by the association of a benign epithe-\nlial component with a malignant mesenchymal component, typically low-grade [7]. \nThis biphasic tumor typically exhibits a morphology where glands are seen associ-\nated with periglandular stromal hypercellularity , displaying a papillary or polypoid \nappearance, with mild-to-moderate cytologic atypia, analogous to a phyllodes tumor \n[7]. Within this tumor, elements of sex cord development and the development of a \nhigh-grade sarcomatous component, typically with rhabdomyosarcomatous differen-\ntiation, can be associated [8, 45].\nFrom a clinical progression standpoint, about 50% of patients exhibit extraovarian \ntumor extension [7]. Due to easy peritoneal dissemination, the possibility of tumor \nrupture, and overdevelopment of high-grade stroma, this type of tumor presents a \nreserved prognosis, particularly in younger patients [7 , 8, 45].\nRecent data from molecular studies have demonstrated that these tumors belong to \nthe category of mesenchymal neoplasms [8].\n4.3.6 Endometrioid stromal sarcoma\nMorphologically , endometrioid stromal sarcoma is a frequently bilateral ovarian \ntumor that exhibits a morphology similar to that of endometrial stroma [7], with \nhigh-grade cytologic atypia associated with marked mitotic activity [45]. It has \n\nA Comprehensive Overview of Endometriosis\n26\nbeen observed that about 50% of patients with this tumor have it in the context of \nendometriosis [7].\nMicroscopically , endometrioid stromal sarcoma associated with endometriosis \nconsists of large spindle cells with an increased nuclear to cytoplasm ratio, associated \nwith spiral-like arterioles, and is more often low-grade than high-grade [7 , 45].\nIn the literature, there is a reported possibility of association between ovarian \nendometrioid stromal sarcoma and synchronous or preexisting endometrial sarcoma, \nsharing a common cytogenetic profile [7 , 8].\nOvarian endometrioid stromal sarcoma is often diagnosed at advanced stages and \nhas a reserved prognosis [45].\n4.3.7 Squamous cell carcinoma\nRarely , primary ovarian squamous cell carcinoma, possibly associated with \nsquamous metaplasia, can occur in a context of endometriosis [7].\nAlthough cases of non-invasive squamous neoplasia with a flat or papillary \nappearance within ovarian cysts, associated with cervical intraepithelial neoplasia, \nhave been described, the suspicion of the role of human papillomavirus (HPV) has \nbeen ruled out in the etiopathogenesis of ovarian involvement due to HPV negativity \nat the ovarian level [7].\n5. Evaluation of a suspicious endometriotic lesion\n5.1 Clinical evaluation\nGiven that 90% of ovarian masses in premenopausal women and 60% of those \nin postmenopausal women prove to be benign [87], assessing the neoplastic risk \nis crucial in guiding diagnostic and therapeutic techniques. The suspicion of \nmalignant transformation is difficult to determine before surgical exploration, as \novarian carcinoma is known as a “silent killer, ” typically diagnosed in advanced \nstages. However, some symptoms and clinical signs can raise an alarm several \nmonths before diagnosis, even from the early stages [88], indicating the necessity \nfor additional preoperative investigations that can facilitate an optimal diagnostic \nand therapeutic approach. Before initiating surgical treatment, obtaining a com-\nplete medical history , including significant familial and genetic risk assessments, is \nmandatory .\nPhysical examination may reveal an abdominopelvic mass with characteristics \nsuggestive of tumor transformation: solid, firm, nodular, fixed to surrounding \nanatomical structures. It should be noted that a very large tumor mass often proves to \nbe a benign or borderline tumor. Rectovaginal examination is important in planning \nsurgical intervention, as if infiltration of the rectovaginal septum is observed, a low \nanterior resection (of the rectosigmoid) may be necessary .\nIf the clinical examination reveals ascitic fluid associated with a pelvic mass, \nan ovarian neoplasm diagnosis should be considered, until proven otherwise. \nEvidently , if there is a suspicion of neoplasia, pulmonary auscultation is manda -\ntory , which might identify pleurisy , as well as examination of the superficial \nlymph node groups.\n\n27\nEndometriosis-Associated Ovarian Carcinoma\nDOI: http://dx.doi.org/10.5772/intechopen.1007677\n5.2 Laboratory findings\nFacing an endometriotic lesion with atypical appearance, a comprehensive \nevaluation is recommended, including a complete blood count. This is necessary \nbefore any surgical intervention and can provide additional clues, considering that \n20–25% of patients with ovarian neoplasia also exhibit thrombocytosis (>400x10 9 /L) \n[89]. Hyponatremia is also commonly identified, generally ranging between 125 and \n135 mEq/L (milliequivalents per liter).\nAmong the tumor markers used to classify patients into risk groups are cancer \nantigen 125 (CA125) and human epididymis protein 4 (HE4). Additionally , two \nalgorithms for calculating neoplastic risk, the “risk of ovarian malignancy algo-\nrithm” (ROMA) and the “risk malignancy index” (RMI), are utilized. The CA125 \nvalue is higher than the cutoff value of 35 U/mL in over 90% of cases of non-muci-\nnous ovarian carcinoma, but interpretation must be cautious, as only 50% of stage \nI carcinomas exhibit this characteristic [90]. The marker also has low specificity , \nwith elevated values also found in endometriosis, as well as in patients with benign \ngynecological pathology or in physiological conditions, such as menstruation, \npregnancy , pelvic inflammatory disease, and also in abdominal diseases, especially \nliver or pancreatic conditions.\nHE4 has a sensitivity of 72.9% and a specificity of 95% in differentiating \nbenign from malignant ovarian tumors, both values being higher than those \nof CA125 [91]. The ROMA score takes into account the values of both markers, \nalong with the patient’ s menopausal status, providing a sensitivity of 88.7% and \na specificity of 74.7% [92]. As for the RMI, it additionally utilizes the ultrasonic \nfeatures of the ovarian tumor, which enhances both the sensitivity and specificity \nof the evaluation.\n5.3 Imaging techniques\nTo differentiate benign from malignant ovarian tumors, the most commonly \nused imaging technique is pelvic ultrasound. When employing this method, the \nInternational Ovarian Tumor Analysis (IOT A) 2018 score is used, which considers \nvarious ultrasonographic aspects of ovarian neoplasia. Characteristics suggestive of \nbenignity include the presence of a unilocular cyst, solid components with a maxi-\nmum diameter of 7 mm, acoustic shadows, a multilocular cyst with a smooth surface \nand maximum diameter of 100 mm, and the absence of blood flow . Indicators of \nmalignancy include the presence of an irregular solid tumor, ascitic fluid, at least four \npapillary structures, an irregular multilocular solid tumor with a maximum diameter \nof 100 mm, and pronounced blood flow [93].\nUltrasound examination is less significant in advanced disease, as it is more diffi-\ncult to interpret and cannot specify all the details necessary for staging. In such cases, \nCT scanning is preferred, which also allows for the assessment of hepatic, retroperi-\ntoneal, omental, or lymph node involvement and can identify the extension of the \ntumor to other locations. CT is not useful in differentiating benign from malignant \novarian tumor masses and is generally used to plan surgical intervention when there \nis a high suspicion of ovarian carcinoma. Other complementary imaging explorations \ninclude MRI and PET . Chest radiography is essential to detect pleural effusion or, less \ncommonly , pulmonary metastases.\n\nA Comprehensive Overview of Endometriosis\n28\n6. Prevention techniques\nIdentification of those endometriomas that contain foci of AE would allow \npreventive measures to be taken in a useful manner. This could lead to either a timely \nsurgery that would prevent the progression towards invasive carcinoma or even \nconservative treatment if the malignancy is detected in early stages, considerably \nreducing the morbidity , the mortality , and the treatment costs.\nSuch measures currently include:\n• early detection of EAOC;\n• risk-reducing medical treatment;\n• risk-reducing surgical treatment.\n6.1 Early detection of EAOC\nEarly detection and treatment of endometriosis-associated ovarian cancer \n(EAOC), which primarily includes endometrioid and clear-cell ovarian carcinomas, \nsignificantly impact long-term outcomes for patients. It plays a crucial role in improv -\ning long-term outcomes for patients by increasing survival rates, reducing recurrence, \nenhancing quality of life, and expanding treatment options. Integrating effective \nscreening and monitoring strategies into clinical practice can help achieve these \nbenefits, ultimately leading to better patient outcomes.\nDetecting EAOC at an early stage (I or II) significantly improves overall survival \nrates. Early-stage cancers are generally confined to the ovary or the pelvis, allowing \nfor complete surgical removal, which is the cornerstone of treatment. Patients diag -\nnosed at these stages typically have a much higher 5-year survival rate compared to \nthose diagnosed at advanced stages (III or IV), where survival rates drop significantly .\nWhen EAOC is detected early , the likelihood of achieving optimal cytoreduction \n(removal of all visible tumor tissue) is much higher. Complete surgical resection is \na critical factor in improving survival, as it reduces tumor burden and enhances the \neffectiveness of adjuvant therapies like chemotherapy or targeted therapies. In contrast, \nadvanced-stage disease often involves widespread metastasis, making complete surgi-\ncal removal more challenging and reducing the chances of achieving optimal outcomes.\nAlso, early detection of EAOC can lead to a greater responsiveness to standard \nplatinum-based chemotherapy , which is less effective in advanced, chemoresistant \ntumors, particularly clear-cell ovarian carcinomas. Early-stage tumors are generally \nsmaller, less aggressive, and more likely to be effectively treated with standard chemo-\ntherapy regimens, which can help prevent recurrence and prolong progression-free \nsurvival. Early detection can reduce the need for aggressive, multi-modal treatments \noften required for advanced-stage EAOC. For early-stage disease, less extensive sur-\ngery , lower doses of chemotherapy , or the use of targeted therapies may suffice, mini-\nmizing the treatment-related toxicity and improving the quality of life for patients.\nFor younger patients diagnosed with early-stage EAOC who wish to preserve fer-\ntility , early detection allows for more conservative surgical options, such as unilateral \nsalpingo-oophorectomy (removal of one ovary and fallopian tube) or cystectomy \n(removal of the cyst only). These approaches may maintain reproductive potential \nwhile still effectively treating the cancer, provided the disease is adequately staged \nand monitored.\n\n29\nEndometriosis-Associated Ovarian Carcinoma\nDOI: http://dx.doi.org/10.5772/intechopen.1007677\nPatients diagnosed with early-stage EAOC also have a lower risk of cancer recur-\nrence compared to those diagnosed at a later stage. Early detection allows for complete \nresection of the tumor and a more effective initial treatment, reducing the likelihood \nof residual disease that could lead to recurrence. Lower recurrence rates are associated \nwith better long-term survival and quality of life.\nThe early detection of EAOC could be obtained by a trained ultrasonographist, as \nthis technique allows complete characterization of the location and extent of endo-\nmetriotic lesions [94]. Supplementary MRI, when available, is useful in detecting \nall locations of endometriosis, especially when ultrasonography has limitations (for \nexample, regarding lesions located above the rectosigmoid junction) [94].\nIn this context, several researchers have raised awareness towards the elements \nof suspicion, pointing out the signs and symptoms that might suggest malignant \ntransformation of an endometriotic cyst. For example, Nezhat et  al. point out that \nan increase of endometrioma size, changing of ultrasonographic characteristics, and \nmural node formation constitute ominous signs that require surgical excision [95]. \nSuspicion is also raised when the patient develops symptoms such as dysmenorrhea \nand dyspareunia or is facing a relapse or worsening pelvic pain symptoms [96]. \nSupplementary , advancing age (over 45 years) and the size of endometriomas (over \n8 cm) were found to be independent predictors of development of ovarian cancer \namong women with ovarian endometrioma [50]. It is generally believed that when \ngynecologists or radiologists with specialized oncological experience evaluate all \nsuspicious endometriomas, the effectiveness of imaging techniques in identifying \ncysts that need surgical removal can be significantly improved. [50].\nIn a recent article, Y ounis et  al. postulate that the overall lifetime risk of a woman \nwith endometriosis to develop EAOC remains minimal [97]. They emphasize the \nimportance of imagistic differentiation between benign, “homogenous cystic ‘ground \nglass’”-appearing endometrioma and EAOC. They consider that suspicious ultrasound \nfindings, such as large, vascularized, papillary , unilateral cysts (>9 cm) with solid \nintracystic projections, should be further characterized by MRI [97 , 98]. In this regard, \nthe non-invasive transvaginal ultrasound is considered a new and promising technique \nin early diagnosis of malignant transformed endometriosis, being able to accurately \nevaluate ovarian masses, the method being doubled by MRI in uncertain cases [99].\n6.2 Risk-reducing medical treatment\nIt is already established that prolonged oral contraceptive use is associated with a \nmajor reduction in the risk of developing an endometrioma, as this medication inhib-\nits ovulation. It can be concluded that oral contraceptives and progestogens should \ntheoretically reduce the risk of EAOC in women with a history of endometriosis, even \nin those without current endometriomas [50]. It is well known that the development \nof endometrioid ovarian cancer is primarily driven by a hormonal environment with \nhigh levels of estrogen and low levels of progesterone. Additionally , high intracystic \nlevels of heme and free iron lead to a state of persistent oxidative stress, which may \nlead to stress-resistant types like clear-cell ovarian carcinoma. In this context, Kim \net  al. propose that the long-term use of oral contraceptives and progestogens in \nwomen with existing endometriomas may reduce the risk of mainly receptor-positive \nendometrioid ovarian cancer to a greater extent than with respect to the risk of \nmainly receptor-negative clear-cell ovarian carcinoma [100]. Overall, the long-term \nuse of oral contraceptives might contribute to the prevention of EAOC by limiting \ndisease progression without detrimental effects on the reproductive potential [101].\n\nA Comprehensive Overview of Endometriosis\n30\n6.3 Risk-reducing surgical treatment\nRegardless of the imagistic aspect and suspicion, some clinicians suggest surgery \nas a method of risk reduction. Even though in younger women diagnosed with \nendometrioma, surgery has specific individual indications and limits, in perimeno-\npausal women removal of ovaries with endometriotic cysts may be taken into consid-\neration. Until now , no robust studies have provided information regarding the effect \nof surveillance compared with that of surgery (unilateral salpingo-oophorectomy \nor cystectomy/partial ovarian excision) on mortality from EAOC in patients with \nendometriosis/endometriomas [50].\nSpecialists suggest that surgery should be considered for endometriomas with a \nprolonged evolution, especially if they are not being hormonally treated (either with \noral contraceptives or with progestogens), and also in the case of de novo detection \nof an endometrioma during medical treatment, as the risk of malignancy appears \nhere to have substantially increased [102, 103]. Moreover, according to Haraguchi \net  al., recurrent endometriomas are at especially augmented risk of malignant \ntransformation, as all EAOCs in their series developed in patients who experienced \na cyst recurrence [104]. In most women with a history of endometriosis but without \nultrasonographic evidence of endometriomas, surveillance rather than risk-reducing \nsalpingo-oophorectomy seems advisable.\n6.4 Clinical applicability of identified risk factors\nIdentified risk factors for EAOC can be utilized in clinical practice to enhance \nscreening, early detection, and prevention strategies.\nIdentifying high-risk individuals, such as personal history of endometriosis or \nfamily history of ovarian or endometrial cancer, could lead to a more personalized \napproach in order to provide them specific screening tools. Clinicians should consider \nmore frequent monitoring and evaluation for ovarian cancer in women with a known \nhistory of endometriosis, particularly those with long-standing or severe endometrio-\nsis, including regular pelvic examinations, transvaginal ultrasounds, and potentially \nadvanced imaging techniques like MRI, if warranted. Regular monitoring of serum \nbiomarkers, such as CA125 and human epididymis protein 4 (HE4) in high-risk \nwomen, could help detect early signs of malignancy , although these markers have \nlimitations in sensitivity and specificity . Combining biomarker analysis with imaging \ntechniques may improve early detection rates.\nAdditionally , women with a family history of ovarian, endometrial, or breast \ncancer may be at increased risk, especially if there is a familial link to conditions like \nLynch syndrome or BRCA mutations. Genetic counseling and testing can be offered to \nthese patients to identify hereditary cancer syndromes and guide risk-reducing strate-\ngies, such as increased surveillance, chemoprevention, or risk-reducing surgeries.\nFor patients with endometriosis, molecular profiling of endometriotic lesions, if \nexcised, may help identify mutations (e.g., ARID1A, PTEN) or hormonal profiles that \nare associated with higher malignancy risk. Women with these profiles may benefit \nfrom closer surveillance.\nClinicians could also implement some risk-reducing interventions, such as hormonal \ntherapy or tailored surgical approaches. Long-term use of hormonal therapies, such as \noral contraceptives or progestins, may reduce the risk of endometrioid ovarian cancer \nin women with endometriosis. Hormonal therapy can create a progesterone-dominant \nenvironment, which has been associated with a lower risk of malignant transformation \n\n31\nEndometriosis-Associated Ovarian Carcinoma\nDOI: http://dx.doi.org/10.5772/intechopen.1007677\nof endometriotic lesions. For women with endometriosis who are considered at high \nrisk for EAOC (e.g., due to family history or genetic mutations), risk-reducing surger-\nies, such as prophylactic oophorectomy (removal of the ovaries) or hysterectomy , may \nbe discussed. Surgical removal of visible endometriotic lesions during laparoscopy can \nalso reduce the risk of malignancy , especially for lesions that are atypical or recurrent.\nLast but not least, patients could benefit from lifestyle modifications, education, \nand awareness. Encouraging lifestyle changes, such as maintaining a healthy weight, \navoiding smoking, and managing stress, can be important preventive measures. \nWhile the direct impact of these factors on EAOC is less clear, a healthy lifestyle is \ngenerally protective against many forms of cancer. Educating patients with endome-\ntriosis about their potentially increased risk of ovarian cancer, particularly if they \nhave additional risk factors, can empower them to participate actively in surveillance \nand prevention strategies. Patients should be informed of symptoms that could sug -\ngest malignant transformation, such as pelvic pain, bloating, or changes in menstrual \npatterns, and seek medical evaluation promptly .\nAdditionally , encouraging eligible high-risk women to participate in clinical trials \naimed at identifying new screening tools, biomarkers, and preventive strategies could \ncontribute to advancing the field and improving outcomes for EAOC.\n7 . Treatment\nThe traditional therapeutic approach included debulking surgery followed by \nadjuvant chemotherapy , with salvage chemotherapy as an option if the initial treat -\nment failed or if there was a recurrence. Nevertheless, due to the recent progress in \ndeciphering the intrinsic mechanisms of endometriosis and of EAOC, the treatment \napproach for EAOC has also evolved. The molecular and pathological characteristics \nof EAOC significantly influence treatment strategies and patient outcomes.\nAccording to the current guidelines, chemotherapeutic option for ovarian drugs \ncancer commonly used in the treatment of ovarian cancer, including in the EAOC, \nincludes platinum-based drugs, such as cisplatin and carboplatin, as well as taxanes, \nsuch as paclitaxel [105, 106].\nHowever, in the advanced stages (FIGO (The International Federation of \nGynecology and Obstetrics) stage III or IV) or recurrent cases, a declining effective-\nness of chemotherapy was noted, leading to a poor prognosis. Consequently , there \nhas been a shift towards enhancing the efficacy of first-line treatment. This involves \nprioritizing aggressive surgical cytoreduction to improve the quality of surgery and \nadopting newer chemotherapy agents, often combined with targeted therapy or \nimmunotherapy , to enhance treatment outcomes. Also, hyperthermic intraperitoneal \nchemotherapy (HIPEC) with perfusion of intraperitoneal chemotherapy during the \nsurgical intervention was introduced in the therapeutic arsenal.\nTaking into account the strong hormone dependence of endometriosis and EAOC, \nhormonotherapy is currently used as another adjuvant systemic treatment option \n[105, 107]. For example, elevated levels of progesterone receptor (PR) in endometri-\noid ovarian carcinoma have been linked to a better prognosis and thus could be poten-\ntial targets for tumors. In this context, high PR expression is generally associated with \na more favorable prognosis and may guide the use of hormone-based therapies, such \nas progestins or anti-estrogen agents (e.g., tamoxifen).\nConversely , the loss of estrogen receptor alpha or the high expression of estrogen \nreceptor beta and gamma have been associated with reduced overall survival in \n\nA Comprehensive Overview of Endometriosis\n32\novarian cancer [108, 109]. In this context, several recent studies have evaluated the \ntherapeutic potential of endocrine agents, such as letrozole, tamoxifen, aromatase \ninhibitors, and fulvestrant, in ovarian cancer, as reviewed by Langdon et  al. [110]. \nSupplementary , estradiol-triazole analogs were developed, with the scope of targeting \nproteins involved in the epidermal growth factor receptor/mitogen-activated protein \nkinase (EGFR/MAPK) pathway in ovarian cancer [111].\nAnother innovative strategy involves incorporating the anti-angiogenic medica -\ntion bevacizumab, a monoclonal antibody that targets vascular endothelial growth \nfactor (VEGF)-A, into first-line treatment alongside chemotherapy . Additionally , \nbevacizumab can be utilized as monotherapy for individuals with newly diagnosed \nadvanced ovarian cancer and platinum-resistant recurrent cases. Moreover, clear-cell \novarian carcinoma often overexpresses VEGF and anti-angiogenic agents, such as \nbevacizumab, can be particularly effective for these tumors.\nMoreover, oral VEGF receptor tyrosine kinase inhibitors like pazopanib and nint -\nedanib have been employed for maintenance therapy in platinum-sensitive recurrent \novarian cancer, offering notable benefits [112].\nThe tumor microenvironment, including immune cell infiltration, can affect \ntreatment responses. Tumors with high immune cell infiltration may be more respon-\nsive to immunotherapy , while those with a suppressed immune microenvironment \nmight require combination treatments to enhance the immune response.\nIn addition to that, the advancement and utilization of anticancer immunotherapies, \ninvolving immune checkpoint inhibitors like anti-cytotoxic T -lymphocyte-associated \nprotein 4 (CTLA-4) and anti-programmed cell death protein 1 (PD-1)/programmed \ndeath-ligand 1 (PD-L1) antibodies, have resulted in notable enhancements in the \nmanagement of diverse cancers. These therapies are particularly effective in combating \nthe evasion of immune-mediated detection and elimination of malignant cells [112].\nRegarding the genetic mutations and alterations with potential therapeutic \ntargeting, it has been shown that EAOCs frequently exhibit mutations in genes, such \nas ARID1A and PTEN, which are implicated in chromatin remodeling and cell growth \nregulation, respectively . These mutations can help identify tumors that might respond \nto targeted therapies, like PI3K/AKT/mTOR inhibitors.\nAlso, some EAOCs may show deficiencies in mismatch repair proteins, leading to \nmicrosatellite instability (MSI). These tumors are often more responsive to immune \ncheckpoint inhibitors (e.g., pembrolizumab), making immunotherapy a viable treat -\nment option.\nInsights into molecular pathways of EAOCs could also lead a way towards person-\nalized therapy . As clear-cell ovarian carcinoma often shows activation of the PI3K/\nAKT/mTOR pathway , it could be a potential candidate for mTOR inhibitors (e.g., \neverolimus) or PI3K inhibitors.\nFurther detailed analysis could provide insights regarding biomarkers for person-\nalized treatment. The presence of specific biomarkers, such as hormone receptors, \nMSI status, and actionable mutations (e.g., BRCA, ARID1A), helps to stratify patients \nfor personalized treatment approaches, potentially improving outcomes by tailoring \ntherapies to the tumor’ s unique molecular profile.\n8. Prognosis\nTaking into consideration the particularities of EAOC, such as the high preva -\nlence of endometrioid or clear-cell ovarian cancer (CCOC) histotypes, it is generally \n\n33\nEndometriosis-Associated Ovarian Carcinoma\nDOI: http://dx.doi.org/10.5772/intechopen.1007677\nconsidered that it has a better prognosis than other types of ovarian cancer, with \nthe exception of advanced stages of clear-cell ovarian cancer, which has an earlier \nrecurrence rate and a lower overall survival rate [113]. In any case, EAOC is usually \ndetected sooner than non-EAOC, which also contributes to the better management \nand prognosis of this neoplasia, but it is unclear whether the association with endo-\nmetriosis actually contributes to this better prognosis, compared to endometrial \ncancer (EC) and CCOC, which are not associated with endometriosis [113]. Similar \nconclusions were reached by Li et  al. [114], who concluded that in patients with \nEAOCs, a significantly longer overall survival was recorded compared to non-EAOC \npatients, probably because the association with endometriosis leads to a higher preva -\nlence of early-stage and low-grade tumors, and thus a much better survival rate than \nnon-EAOC. These survival analysis findings showed that stage at diagnosis seems \nto be more important to prognosis than association with endometriosis alone [114]. \nUltimately , the molecular and pathological characteristics of EAOC significantly \ninfluence treatment strategies and outcomes. By understanding these characteristics, \nclinicians can better tailor therapies to individual patients, potentially improving \nresponse rates and survival outcomes.\nIn conclusion, endometriosis-associated ovarian cancer (EAOC), encompassing \nprimarily endometrioid and clear-cell ovarian carcinomas, represents a distinct \nsubset of ovarian malignancies with unique molecular and pathological character-\nistics that directly influence patient management and outcomes. Early detection \nremains pivotal, as it markedly improves survival rates, enhances responsiveness to \nstandard treatments, and allows for more conservative approaches, including fertil-\nity preservation in younger patients. Understanding the role of hormonal environ-\nments, genetic mutations, and the molecular pathways driving the transformation \nfrom endometriosis to EAOC has led to more personalized treatment strategies and \nimproved patient care.\nHowever, significant gaps in knowledge persist. Future research should focus \non developing reliable, non-invasive biomarkers and advanced imaging techniques \nfor early detection, particularly in high-risk women. Additionally , a deeper under -\nstanding of the molecular mechanisms underlying the progression of endometriosis \nto malignancy is crucial to identifying new therapeutic targets. Research should \nalso explore the role of the tumor microenvironment and the immune system’ s \ninvolvement in EAOC progression to optimize the use of immunotherapies and \ntargeted treatments. Addressing these unresolved questions will be key to advanc -\ning the field, improving early detection, and ultimately providing better outcomes \nfor patients with EAOC.\n\nA Comprehensive Overview of Endometriosis\n34\nAuthor details\nIoana Pavaleanu*, Teodora Ana Balan, Tiberiu Nicolae Poparlan, Ana Maria Haliciu,  \nTudor Andrei Butureanu, Ana Maria Apetrei, Razvan Socolov , Andreea Ioana Pruteanu \nand Raluca Anca Balan\nGr. T . Popa University of Medicine and Pharmacy , Iași, Romania\n* Address all correspondence to: ioana_pavaleanu@yahoo.com\n© 2024 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of \nthe Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), \nwhich permits unrestricted use, distribution, and reproduction in any medium, provided \nthe original work is properly cited. \n\nEndometriosis-Associated Ovarian Carcinoma\nDOI: http://dx.doi.org/10.5772/intechopen.1007677\n35\nReferences\n[1] Audebert A, Petousis S, Margioula- \nSiarkou C, Ravanos K, Prapas N, \nPrapas Y . Anatomic distribution of \nendometriosis: A reappraisal based \non series of 1101 patients. European \nJournal of Obstetrics, Gynecology , and \nReproductive Biology . 2018;230:36-40\n[2] V an Gorp T , Amant F , Neven P , et  al. \nEndometriosis and the development \nof malignant tumours of the pelvis. \nA review of literature. Best Practice \n& Research. Clinical Obstetrics & \nGynaecology . 2004;18 :349-371\n[3] Hanahan D, W einberg RA. \nThe hallmarks of cancer. Cell. \n2000; 100(1):57-70\n[4] Hanahan D, W einberg RA. The \nhallmarks of cancer: The next generation. \nCell. 2011;144 (5):646-674\n[5] Scott R. Malignant change in \nendometriosis. Obstetrics and \nGynecology . 1953;2:293-299\n[6] Maeda D, Shih IM. Pathogenesis \nand the role of ARID1A mutation \nin endometriosis-related ovarian \nneoplasms. Advances in Anatomic \nPathology . 2013;20 :45-52\n[7] Mikami Y . Endometriosis-related \novarian neoplasms: Pathogenesis and \nhistopathologic features. Diagnostic \nHistopathology . 2014;20 :357-363\n[8] Matias-Guiu X, Stewart CJR. \nEndometriosis-associated ovarian \nneoplasia. Pathology . 2018;50(2):190-204\n[9] Taniguchi F . New knowledge \nand insights about the malignant \ntransformation of endometriosis. The \nJournal of Obstetrics and Gynaecology \nResearch. 2017;43 (7):1093-1100\n[10] Zeitvogel A, Baumann R, \nStarzinski-Powitz A. Identification of \nan invasive, N-cadherin-expressing \nepithelial cell type in endometriosis \nusing a new cell culture model. The \nAmerican Journal of Pathology . \n2001; 159(5):1839-1852\n[11] Park SH, Cheung LW , W ong AS, \net  al. Estrogen regulates snail and slug \nin the down-regulation of E-cadherin \nand induces metastatic potential of \novarian cancer cells through estrogen \nreceptor alpha. Molecular Endocrinology . \n2008; 22:2085-2098\n[12] Chen S, Dai X, Gao Y , et  al. \nThe positivity of estrogen receptor \nand progesterone receptor may not \nbe associated with metastasis and \nrecurrence in epithelial ovarian cancer. \nScientific Reports. 2017;7(1):16922\n[13] Tkalia IG, V orobiova LI, Svintsisky , \net  al. Clinical significance of hormonal \nreceptor status of malignant ovarian \ntumors. Experimental Oncology . \n2014; 36:125-133\n[14] Lai CR, Hsu CY , Chen YJ, \net  al. Ovarian cancers arising from \nendometriosis: A microenvironmental \nbiomarker study including ER, \nHNF1ß, p53, PTEN, BAF250a, and \nCOX-2. Journal of the Chinese Medical \nAssociation. 2013;76 :629-634\n[15] Scholzen T , Gerdes J. The Ki-67 \nprotein: From the known and the \nunknown. Journal of Cellular Physiology . \n2000; 182:311-322\n[16] Matsumoto T , Y amazaki M, \nTakahashi H, et  al. Distinct β-catenin \nand PIK3CA mutation profiles in \nendometriosis-associated ovarian \nendometrioid and clear cell carcinomas. \n\nA Comprehensive Overview of Endometriosis\n36\nAmerican Journal of Clinical Pathology . \n2015; 144(3):452-463\n[17] Kvaskoff M et  al. Endometriosis and \ncancer: A systematic review and meta-\nanalysis. Human Reproduction Update. \n2021;27(2):393-420\n[18] Thomsen LH, Schnack TH, \nBuchardi K, et  al. Risk factors of \nepithelial ovarian carcinomas among \nwomen with endometriosis: A systematic \nreview . Acta Obstetricia et Gynecologica \nScandinavica. 2017;96:761-778\n[19] Wang L, Li X, Wang Y , Li G, \nDai S, Cao M, et  al. Endometriosis and \nepithelial ovarian cancer: A two-sample \nMendelian randomization analysis. \nScientific Reports. 2023;13 (1):21992. \nDOI: 10.1038/s41598-023-49276-x\n[20] Treloar SA, Wicks J, Nyholt DR, et  al. \nGenome-wide linkage study in 1,176 \naffected sister pair families identifies \nsignificant susceptibility locus for \nendometriosis on chromosome 20q26. \nAmerican Journal of Human Genetics. \n2005; 77:365-376\n[21] Uno S, Zembutsu H, Hirasawa A, \net  al. A genome-wide association study \nidentifies genetic variants in the \nCDKN2BAS locus associated with \nendometriosis in Japanese. Nature \nGenetics. 2010;42 (8):707-710\n[22] Painter JN, Anderson CA, \nNyholt DR, et  al. Genome-wide \nassociation study identifies a locus at \n7p15.2 associated with the development \nof endometriosis. Nature Genetics. \n2011; 43(1):51-54\n[23] Sato N, Tsunoda H, Nishida M, et  al. \nLoss of heterozygosity on 10q23.3 and \nmutation of the tumor suppressor gene \nPTEN in benign endometrial cyst of the \novary: Possible sequence progression \nfrom benign endometrial cyst to \nendometrioid carcinoma and clear cell \ncarcinoma of the ovary . Cancer Research. \n2000; 60(24):7052-7056\n[24] Goumenou AG, Arvanitis DA, \nMatalliotakis IM, et  al. Microsatellite \nDNA assays reveal an allelic imbalance in \np16 (Ink4), GALT , p53, and APOA2 loci \nin patients with endometriosis. Fertility \nand Sterility . 2001;75 (1):160-165\n[25] Nakayama K, Toki T , Nikaido T , \net  al. Genetic alterations in microsatellite \nmarker sites among tumor suppressor \ngenes in endometriosis. Gynecologic \nand Obstetric Investigation. \n2001; 51(4):240-242\n[26] Bischoff FZ, Heard M, \nSimpson JL. Somatic DNA alterations \nin endometriosis: High frequency of \nchromosome 17 and p53 loss in late stage \nendometriosis. Journal of Reproductive \nImmunology . 2002;55(1-2):49-64\n[27] Hsieh YY , Chang CC, Tsai FJ, et  al. \nGlutathione S-transferase M1 null \ngenotype but not myeloperoxidase \npromoter G-463A polymorphism is \nassociated with higher susceptibility \nto endometriosis. Molecular Human \nReproduction. 2004;10 (10):713-717\n[28] Dinulescu DM, Ince T A, \nQuade BJ, et  al. Role of K-ras and Pten \nin the development of mouse models \nof endometriosis and endometrioid \novarian cancer. Nature Medicine. \n2005; 11(1):63-70\n[29] Govatati S, Kodati VL, \nDeenadayal M, et  al. Mutations in \nthe PTEN tumor gene and risk \nof endometriosis: A case-control \nstudy . Human Reproduction. \n2014; 29(2):324-336\n[30] Maeda N, Izumiya C, Taniguchi K, \net  al. Role of NK cells and HLA-G in \nendometriosis. Frontiers in Bioscience. \n2012; 4:1568-1581\n\nEndometriosis-Associated Ovarian Carcinoma\nDOI: http://dx.doi.org/10.5772/intechopen.1007677\n37\n[31] Lamceva J, Uljanovs R, Strumfa I. \nThe Main theories on the pathogenesis of \nendometriosis. International Journal of \nMolecular Sciences. 2023;24 (5):4254\n[32] Signorile PG, Viceconte R, \nBaldi A. New insights in pathogenesis \nof endometriosis. Frontiers in Medicine \n(Lausanne). 2022;9:879015\n[33] Kao AP , Wang KH, Chang CC, \net  al. Comparative study of human \neutopic and ectopic endometrial \nmesenchymal stem cells and the \ndevelopment of an in vivo endometriotic \ninvasion model. Fertility and Sterility . \n2011; 95(4):1308-1315\n[34] Kitawaki J, Kado N, Ishihara H, et  al. \nEndometriosis: The pathophysiology \nas an estrogen-dependent disease. The \nJournal of Steroid Biochemistry and \nMolecular Biology . 2002;83 (1-5, 155):149\n[35] Dun EC, Taylor RN, Wieser F .  \nAdvances in the genetics of \nendometriosis. Genome Medicine. \n2010; 2(10):75\n[36] van der Linden PJ. Theories on the \npathogenesis of endometriosis. Human \nReproduction. 1996;11(3):53-65\n[37] Cosin R, Gilabert-Estelles J, \nRamon LA, et  al. Influence of peritoneal \nfluid on the expression of angiogenic \nand proteolytic factors in cultures of \nendometrial cells from women with \nendometriosis. Human Reproduction. \n2010; 25(2):398-405\n[38] Machado DE, Berardo PT , \nPalmero CY , et  al. Higher expression \nof vascular endothelial growth factor \n(VEGF) and its receptor VEGFR-2 (Flk-\n1) and metalloproteinase-9 (MMP-9) in \na rat model of peritoneal endometriosis \nis similar to cancer diseases. Journal \nof Experimental & Clinical Cancer \nResearch. 2010;29 :4\n[39] Sotnikova NY , Antsiferova YS, \nPosiseeva L V , et  al. Mechanisms \nregulating invasiveness and growth of \nendometriosis lesions in rat experimental \nmodel and in humans. Fertility and \nSterility . 2010;93 (8):2701-2705\n[40] Sinaii N, Cleary SD, Ballweg ML, \net  al. High rates of autoimmune and \nendocrine disorders, fibromyalgia, \nchronic fatigue syndrome and \natopic diseases among women with \nendometriosis: A survey analysis. Human \nReproduction. 2002;17 :2715-2724\n[41] V an V oorhis BJ, Stovall DW . \nAutoantibodies and infertility: A review \nof the literature. Journal of Reproductive \nImmunology . 1997;33 :239-256\n[42] Nisolle M, Alvarez ML, Colombo M, \net  al. Pathogenesis of endometriosis. \nGynécologie, Obstétrique & Fertilité. \n2007; 35(9):898-903\n[43] Sampson JA. Metastatic or embolic \nendometriosis, due to the menstrual \ndissemination of endometrial tissue into \nthe venous circulation. The American \nJournal of Pathology . 1927;3(2):93-110.43\n[44] Cochrane DR, Tessier-Cloutier B, \nLawrence KM, Nazeran T , Karnezis AN, \nSalamanca C, et  al. Clear cell and \nendometrioid carcinomas: Are their \ndifferences attributable to distinct cells \nof origin? The Journal of Pathology . \n2017; 243(1):26-36\n[45] Kurman RJ, Carcangiu ML, \nHerrington CS, Y oung RH, editors. WHO \nClassification of Tumours of Female \nReproductive Organs. 4th ed. Lyon: \nInternational Agency for Research on \nCancer; 2014\n[46] Lopez N, Grabowski JP , De \nSantiago J, Zapardiel I. Carcinoma of the \nrecto-vaginal septum. Comprehensive \nliterature review . Journal of Obstetrics \nand Gynaecology . 2016;36 :450-454\n\nA Comprehensive Overview of Endometriosis\n38\n[47] Cozzolino M, Nasioudis D, Sisti G, \nCoccia ME. Malignant transformation \nof vaginal endometriosis - A review of \nliterature. Gynecologic and Obstetric \nInvestigation. 2017;82 :105-112\n[48] Kurman RJ, Shih IeM. The dualistic \nmodel of ovarian carcinogenesis: \nRevisited, revised, and expanded. \nThe American Journal of Pathology . \n2016; 186(4):733-747\n[49] Karnezis AN, Cho KR, Gilks CB, \nPearce CL, Huntsman DG. The disparate \norigins of ovarian cancers: Pathogenesis \nand prevention strategies. Nature \nReviews. Cancer. 2017;17 :65-74\n[50] V ercellini P , Viganò P , Buggio L, \nMakieva S, Scarfone G, Cribiù FM, et  al. \nPerimenopausal management of ovarian \nendometriosis and associated cancer risk: \nWhen is medical or surgical treatment \nindicated? Best Practice & Research. \nClinical Obstetrics & Gynaecology . \n2018; 51:151-168. DOI: 10.1016/j.\nbpobgyn.2018.01.017\n[51] Y achida N, Y oshihara K, Y amaguchi M, \nSuda K, Tamura R, Enomoto T . How \ndoes endometriosis Lead to ovarian \ncancer? The molecular mechanism of \nendometriosis-associated ovarian cancer \ndevelopment. Cancers. 2021;13 (6):1439. \nDOI: 10.3390/cancers13061439\n[52] Wiegand KC, Hennessy BT , Leung S, \nWang Y , Ju Z, McGahren M, et  al. A \nfunctional proteogenomic analysis of \nendometrioid and clear cell carcinomas \nusing reverse phase protein array \nand mutation analysis: Protein \nexpression is histotype-specific \nand loss of ARID1A/BAF250a is \nassociated with AKT phosphorylation. \nBMC Cancer. 2014;14 :120. \nDOI: 10.1186/1471-2407-14-120\n[53] Steinbuch SC, Lüß AM, Eltrop S,  \nGötte M, Kiesel L. Endometriosis- \nassociated ovarian cancer: From \nmolecular pathologies to clinical \nrelevance. International Journal of \nMolecular Sciences. 2024;25 (8):4306. \nDOI: 10.3390/ijms25084306\n[54] Huang HN, Lin MC, Huang WC, \nChiang YC, Kuo KT . Loss of ARID1A \nexpression and its relationship with \nPI3K-Akt pathway alterations and \nZNF217 amplification in ovarian clear \ncell carcinoma. Modern Pathology . \n2014; 27:983-990\n[55] Ackroyd SA, Arguello D, Ramos P , \nMahdi H, ElNaggar A, Winer I, et  al. \nMolecular portraits of clear cell \novarian and endometrial carcinoma \nwith comparison to clear cell renal cell \ncarcinoma. Gynecologic Oncology . \n2023; 169:164-171\n[56] Driva TS, Schatz C, Haybaeck J. \nEndometriosis-associated ovarian \ncarcinomas: How PI3K/AKT/mTOR \npathway affects their pathogenesis. \nBiomolecules. 2023;13 :1253\n[57] Martini M, Ciccarone M, \nGarganese G, Maggiore C, Evangelista A, \nRahimi S, et  al. Possible involvement \nof hMLH1, p16(INK4a) and PTEN \nin the malignant transformation of \nendometriosis. International Journal of \nCancer. 2002;102 :398-406\n[58] Er TK, Su YF , Wu CC, Chen CC, \nWang J, Hsieh TH, et  al. Targeted next-\ngeneration sequencing for molecular \ndiagnosis of endometriosis-associated \novarian cancer. Journal of Molecular \nMedicine. 2016;94 :835-847\n[59] Ren F , Wang D, Jiang Y , Ren F . \nEpigenetic inactivation of hMLH1 in the \nmalignant transformation of ovarian \nendometriosis. Archives of Gynecology \nand Obstetrics. 2012;285 :215-221\n[60] Ren F , Wang DB, Li T , Chen YH, \nLi Y . Identification of differentially \n\nEndometriosis-Associated Ovarian Carcinoma\nDOI: http://dx.doi.org/10.5772/intechopen.1007677\n39\nmethylated genes in the malignant \ntransformation of ovarian endometriosis. \nJournal of Ovarian Research. 2014;7:73\n[61] Stejskalová A, Fincke V , Nowak M, \nSchmidt Y , Borrmann K, vonWahlde MK, \net  al. Collagen I triggers directional \nmigration, invasion and matrix \nremodeling of stroma cells in a 3D \nspheroid model of endometriosis. \nScientific Reports. 2021;11:4115\n[62] Szubert M, Nowak-Glück A, \nDomańska-Senderowska D, Szymańska B, \nSowa P, Rycerz A , et  al. miRNA expression \nprofiles in ovarian endometriosis and two \ntypes of ovarian cancer-endometriosis-\nassociated ovarian cancer and high-grade \novarian cancer. International Journal of \nMolecular Sciences. 2023;24 :17470\n[63] Körner M, Burckhardt E, \nMazzucchelli L. Higher frequency of \nchromosomal aberrations in ovarian \nendometriosis compared to extragonadal \nendometriosis: A possible link to \nendometrioid adenocarcinoma. Modern \nPathology . 2006;19 :1615-1623\n[64] Marí-Alexandre J, Carcelén AP , \nAgababyan C, Moreno-Manuel A, \nGarcía-Oms J, Calabuig-Fariñas S, et  al. \nInterplay between MicroRNAs and \noxidative stress in ovarian conditions \nwith a focus on ovarian cancer and \nendometriosis. International Journal of \nMolecular Sciences. 2019;20 :5322\n[65] Banz C, Ungethuem U, Kuban RJ, \nDiedrich K, Lengyel E, Hornung D. The \nmolecular signature of endometriosis-\nassociated endometrioid ovarian cancer \ndiffers significantly from endometriosis-\nindependent endometrioid ovarian \ncancer. Fertility and Sterility . \n2010; 94:1212-1217\n[66] Scarfone G, Bergamini A, Noli S, \nVilla A, Cipriani S, Taccagni G, et  al. \nCharacteristics of clear cell ovarian \ncancer arising from endometriosis: A \ntwo center cohort study . Gynecologic \nOncology . 2014;133 :480e4\n[67] Guan B, Wang TL, Shih IeM. \nARID1A, a factor that promotes \nformation of SWI/SNF-mediated \nchromatin remodeling, is a tumor \nsuppressor in gynecologic cancers. \nCancer Research. 2011;71 :6718e27\n[68] Irving JA, Clement PB, Kurman RJ, \nEllenson LH, Ronnett BM, editors. \nDiseases of the Peritoneum in Blaustein’ s \nPathology of the Female Genital Tract. \n7th ed. Springer; 2019. pp.  771-840\n[69] Parker RL, Dadmanesh F , Y oung RH, \nClement PB. Polypoid endometriosis: \nA clinicopathologic analysis of 24 cases \nand a review of the literature. The \nAmerican Journal of Surgical Pathology . \n2004; 28(3):285-297\n[70] Tsai C, Huang SH, Huang CY . \nPolypoid endometriosis – A rare entity \nof endometriosis mimicking ovarian \ncancer. Taiwanese Journal of Obstetrics \n& Gynecology . 2019;58 :328-329\n[71] Li J, Shi Y , Zhou C, Lin J. \nDiagnosis and treatment of perineal \nendometriosis: Review of 17 cases. \nArchives of Gynecology and Obstetrics. \n2015; 292(6):1295-1299\n[72] McCluggage WG. Endometriosis-\nrelated pathology: A discussion \nof selected uncommon benign, \npremalignant and malignant lesions. \nHistopathology . 2020;76 (1):76-92\n[73] Singh AK, Gogoi P , Diwaker P ,  \nAdhlakha B, Gayatree A. Osseous \nmetaplasia of ovarian cyst: A rare case \nreport. International Surgery Journal. \n2018; 5(9):3164-3166\n[74] Fukunaga M, Ushigome S. Epithelial \nmetaplastic changes in ovarian \n\nA Comprehensive Overview of Endometriosis\n40\nendometriosis. Modern Pathology . \n1998;11(8):784-788\n[75] W epy C, Nucci MR, Parra-Herran C. \nAtypical endometriosis: Comprehensive \ncharacterization of clinicopathologic, \nimmunohistochemical, and \nmolecular features. International \nJournal of Gynecological Pathology . \n2024; 43(1):70-77\n[76] Tanase Y , Furukawa N, Kobayashi H, \nMatsumoto T . Malignant transformation \nfrom endometriosis to atypical \nendometriosis and finally to \nendometrioid adenocarcinoma within \n10 years. Case Reports in Oncology . \n2013;6(3):480-484\n[77] Fukunaga M, Nomura K, \nIshikawa E, Ushigome S. Ovarian atypical \nendometriosis: Its close association \nwith malignant epithelial tumours. \nHistopathology . 1997;30:249-255\n[78] LaGrenade A, Silverberg SG. \nOvarian tumors associated with atypical \nendometriosis. Human Pathology . \n1988;19 :1080-1084\n[79] Czernobilsky B, Morris WJ. A \nhistologic study of ovarian endometriosis \nwith emphasis on hyperplastic and \natypical changes. Obstetrics and \nGynecology . 1979;53 :318-323\n[80] Ogawa S, Kaku T , Amada S, et  al. \nOvarian endometriosis associated with \novarian carcinoma: A clinicopathological \nand immunohistochemical \nstudy . Gynecologic Oncology . \n2000; 77(2):298-304\n[81] Stamp J, Gilks B, W esseling M, \nEshragh S, Ceballos K, Anglesio MS, \net al. Baf250a expression in atypical \nendometriosis and endometriosis-\nassociated ovarian cancer. International \nJournal of Gynecological Cancer. \n2016; 26(5):825-832\n[82] Labidi-Galy SI, Papp E, Hallberg D, \nNiknafs N, Adleff V , Noe M, et  al. High \ngrade serous ovarian carcinomas \noriginate in the fallopian tube. Nature \nCommunications. 2017;8:1093\n[83] Karst AM, Drapkin R. The new \nface of ovarian cancer modeling: Better \nprospects for detection and treatment. \nFaculty of 1000 Medicine Reports. \n2011; 3:22\n[84] Jelovac D, Armstrong DK. Recent \nprogress in the diagnosis and treatment \nof ovarian cancer. CA: A Cancer Journal \nfor Clinicians. 2011;61 (3):183-203. \nDOI: 10.3322/caac.20113\n[85] Soslow RA. Histologic subtypes \nof ovarian carcinoma: An overview . \nInternational Journal of Gynecological \nPathology . 2008;27(2):161-174. \nDOI: 10.1097/PGP .0b013e31815ea812\n[86] DeLair D, Oliva E, Köbel M,  \nMacias A, Gilks CB, Soslow RA.  \nMorphologic spectrum of \nimmunohistochemically characterized \nclear cell carcinoma of the ovary: A study \nof 155 cases. The American Journal of \nSurgical Pathology . 2011;35(1):36-44. \nDOI: 10.1097/P AS.0b013e3181ff400e\n[87] Enakpene CA, Omigbodun AO, \nGoecke TW , et  al. Preoperative \nevaluation and triage of women with \nsuspicious adnexal masses using risk \nof malignancy index. The Journal of \nObstetrics and Gynaecology Research. \n2009; 35(1):131-138\n[88] Goff BA, Mandel L, Muntz HG, et  al. \nOvarian carcinoma diagnosis. Cancer. \n2000; 89(10):2068-2075\n[89] Li AJ, Madden AC, Cass I, et  al. \nThe prognostic significance of \nthrombocytosis in epithelial ovarian \ncarcinoma. Gynecologic Oncology . \n2004; 92:211\n\nEndometriosis-Associated Ovarian Carcinoma\nDOI: http://dx.doi.org/10.5772/intechopen.1007677\n41\n[90] Urban N, McIntosh MW , \nAndersen M, et  al. Ovarian cancer \nscreening. Hematology/Oncology Clinics \nof North America. 2003;17 (4):989-1005\n[91] Moore RG, Brown AK, Miller MC, \net  al. The use of multiple novel tumor \nbiomarkers for the detection of \novarian carcinoma in patients with a \npelvic mass. Gynecologic Oncology . \n2008; 108(2):402-408\n[92] Moore RG, McMeekin DS, \nBrown AK, et  al. A novel multiple marker \nbioassay utilizing HE4 and CA125 for \nthe prediction of ovarian cancer in \npatients with a pelvic mass. Gynecologic \nOncology . 2009;112(1):4046\n[93] Meys EM, Kaijser J, Kruitwagen RF , \nSlangen BF , V an Calster B, \nAertgeerts B, et  al. Subjective assessment \nversus ultrasound models to diagnose \novarian cancer: A systematic review \nand meta-analysis. European Journal of \nCancer. 2016;58 :17-29. DOI: 10.1016/j.\nejca.2016.01.007\n[94] Exacoustos C, Manganaro L, \nZupi E. Imaging for the evaluation of \nendometriosis and adenomyosis. Best \nPractice & Research. Clinical Obstetrics \n& Gynaecology . 2014;28 (5):655-681. \nDOI: 10.1016/j.bpobgyn.2014.04.010\n[95] Nezhat FR, Apostol R, Nezhat C, \nPejovic T . New insights in the \npathophysiology of ovarian cancer \nand implications for screening \nand prevention. American Journal \nof Obstetrics and Gynecology . \n2015; 213:262e7\n[96] Samartzis EP , Noske A, Dedes KJ, \nFink D, Imesch P . ARID1A mutations \nand PI3K/AKT pathway alterations \nin endometriosis and endometriosis-\nassociated ovarian carcinomas. \nInternational Journal of Molecular \nSciences. 2013;14 :18824e49\n[97] Y ounis J. Should endometriosis-\nassociated ovarian cancer alter the \nmanagement of women with an intact \nendometrioma in the reproductive age? \nReproductive Medicine. 2023;4:100-105\n[98] Zhang X, Li M, Tang Z, Li X, Song T . \nDifferentiation between endometriosis-\nassociated ovarian cancers and non-\nendometriosis-associated ovarian cancers \nbased on magnetic resonance imaging. \nThe British Journal of Radiology . \n2021;94 :20201441\n[99] Kobayashi H. Clinicopathological \ncharacteristics, molecular features \nand novel diagnostic strategies for the \ndetection of malignant transformation \nof endometriosis (review). Experimental \nand Therapeutic Medicine. 2023;25 (6):279\n[100] Kim HS, Kim TH, Chung HH, \nSong YS. Risk and prognosis of ovarian \ncancer in women with endometriosis: A \nmeta-analysis. British Journal of Cancer. \n2014; 110:1878-1890\n[101] V ercellini P , Bandini V , Viganò P , \nAmbruoso D, Cetera GE, Somigliana E. \nProposal for targeted, neo-evolutionary-\noriented secondary prevention of early-\nonset endometriosis and adenomyosis. \nPart II: Medical interventions. Human \nReproduction. 2024;39 :18-34\n[102] Tanase Y , Kawaguchi R, \nTakahama J, Kobayashi H. Factors that \ndifferentiate between endometriosis-\nassociated ovarian cancer and benign \novarian endometriosis with mural \nnodules. Magnetic Resonance in Medical \nSciences. 2018;17 (3):231-237\n[103] Kuo HH, Huang CY , Ueng SH, \nHuang KG, Lee CL, Y en CF . Unexpected \nepithelial ovarian cancers arising from \npresumed endometrioma: A 10-year \nretrospective analysis. Taiwanese \nJournal of Obstetrics & Gynecology . \n2017; 56:55e61\n\nA Comprehensive Overview of Endometriosis\n42\n[104] Haraguchi H, Koka K, Takamura M, \nMakabe T , Sue F , Miyashita M, et  al. \nDevelopment of ovarian cancer after \nexcision of endometrioma. Fertility and \nSterility . 2016;106 :1432-1437 .e2\n[105] Armstrong DK, Alvarez RD, \nBakkum-Gamez JN, Barroilhet L, \nBehbakht K, Berchuck A, et  al. Ovarian \ncancer, version 2.2020, NCCN clinical \npractice guidelines in oncology . Journal \nof the National Comprehensive Cancer \nNetwork : JNCCN. 2021;19 :191-226\n[106] Ledermann JA, Matias-Guiu X, \nAmant F , Concin N, Davidson B, \nFotopoulou C, et  al. ESGO-ESMO-ESP \nconsensus conference recommendations \non ovarian cancer: Pathology and \nmolecular biology and early , advanced \nand recurrent disease. Annals of \nOncology . 2024;35:248-266\n[107] Gil-Martin M, Pardo B, \nBarretina-Ginesta MP . Rare ovarian \ntumours. Other treatments for ovarian \ncancer. European Journal of Cancer \nSupplements. 2020;15 :96-103\n[108] Hollis RL, Stanley B, Iida Y , \nThomson J, Churchman M, Rye T , et  al. \nHormone receptor expression patterns \ndefine clinically meaningful subgroups \nof endometrioid ovarian carcinoma. \nGynecologic Oncology . 2019;155:318-323\n[109] Schüler- Toprak S, W eber F , \nSkrzypczak M, Ortmann O, Treeck O. \nExpression of estrogen-related receptors \nin ovarian cancer and impact on survival. \nJournal of Cancer Research and Clinical \nOncology . 2021;147 :2555-2567\n[110] Langdon SP , Herrington CS, \nHollis RL, Gourley C. Estrogen Signaling \nand its potential as a target for therapy in \novarian cancer. Cancers. 2020;12 :1647\n[111] Ostlund T , Alotaibi F , \nKyeremateng J, Halaweish H, Kasten A, \nIram S, et  al. Triazole-estradiol analogs: \nA potential cancer therapeutic targeting \novarian and colorectal cancer. Steroids. \n2022; 177:108950\n[112] Su KM, Wang PH, Yu MH, \nChang CM, Chang CC. The recent \nprogress and therapy in endometriosis-\nassociated ovarian cancer. Journal \nof the Chinese Medical Association. \n2020; 83(3):227-232. DOI: 10.1097/\nJCMA.0000000000000262\n[113] Livori K, Calleja-Agius J. Rare \nbut still there: A scoping review on \nendometriosis-associated ovarian cancer. \nDiscovery Medicine. 2024;36 (182):467-\n481. DOI: 10.24976/Discov .\nMed.202436182.44\n[114] Li Q, Sun Y , Zhang X, Wang L, \nWu W , Wu M, et  al. Endometriosis-\nassociated ovarian cancer is a single \nentity with distinct clinicopathological \ncharacteristics. Cancer Biology & \nTherapy . 2019;20 (7):1029-1034. \nDOI: 10.1080/15384047 .2019.1595278\n\n43\nChapter 3\nMedical Treatment for \nEndometriosis\nMerve Konal\nAbstract\nEndometriosis is a chronic gynecological condition characterized by the presence \nof endometrial-like tissue outside the uterus, leading to pain, inflammation, and \ninfertility . This chapter provides a comprehensive overview of the medical treatments \nfor endometriosis, emphasizing hormonal and non-hormonal therapies, emerging \nand experimental treatments, and lifestyle modifications. Hormonal treatments such \nas oral contraceptives, GnRH agonists and antagonists, progestins, and aromatase \ninhibitors are explored in detail, highlighting their mechanisms of action, efficacy , \nand side effects. Non-hormonal treatments, including pain management strategies \nand complementary therapies, are discussed for their role in alleviating symp-\ntoms and improving quality of life. The chapter also delves into novel therapeutic \napproaches like immunomodulatory drugs, gene therapy , and stem cell therapy , \nwhich hold promise for more effective and personalized management of endome-\ntriosis. Comparative effectiveness research and patient outcomes are analyzed to \nprovide insights into the most effective treatment strategies. Finally , the importance \nof integrating lifestyle modifications and patient education into a comprehensive \ntreatment plan is underscored to enhance long-term management and quality of life \nfor endometriosis patients.\nKeywords: endometriosis, hormonal treatments, non-hormonal treatments,  \nemerging therapies, lifestyle modifications, patient outcomes, pain management,  \ngene therapy , immunomodulatory drugs, stem cell therapy\n1. Introduction\n1.1 Overview and epidemiology\nEndometriosis is a prevalent yet often misunderstood condition that significantly \nimpacts the quality of life for many women globally . It is estimated that approximately \n10% of women of reproductive age suffer from endometriosis, translating to roughly \n176 million women worldwide [1]. Despite its high prevalence, endometriosis is \nfrequently underdiagnosed or diagnosed late, with an average delay of 7–10 years \nfrom symptom onset to diagnosis. This delay is partly due to the wide variability in \nsymptom presentation and the overlap of symptoms with other gynecological and \ngastrointestinal disorders [2].\n\nA Comprehensive Overview of Endometriosis\n44\nThe epidemiology of endometriosis reveals certain patterns and risk factors. \nW omen with a family history of endometriosis are at a higher risk, suggesting \na genetic predisposition. Additionally , early menarche, short menstrual cycles, \nand heavy menstrual bleeding have been identified as potential risk factors [3]. \nEndometriosis is also more common in women who have never given birth, further \ncomplicating their reproductive health and fertility .\nGeographical and racial differences in the prevalence of endometriosis have been \nobserved, although the reasons for these variations are not entirely understood. \nStudies indicate that endometriosis may be more commonly diagnosed in women \nof Asian descent compared to other racial groups, while the condition appears less \nfrequently in African American women [4]. These differences could be attributed to \ngenetic, environmental, and socioeconomic factors, as well as disparities in access to \nhealthcare and diagnostic services.\n1.2 Pathophysiology and etiology\nThe pathophysiology of endometriosis is complex and multifactorial, involving \ngenetic, hormonal, and immunological factors. The most widely accepted theory is \nthat of retrograde menstruation, which suggests that menstrual blood flows back-\nward through the fallopian tubes into the pelvic cavity , allowing endometrial cells to \nimplant and grow outside the uterus [5]. However, this theory does not fully explain \nall cases of endometriosis, as retrograde menstruation occurs in many women who do \nnot develop the condition.\nAnother significant theory is coelomic metaplasia, which proposes that peritoneal \ncells can transform into endometrial cells under certain conditions. This theory is \nsupported by the presence of endometriosis in locations outside the pelvis, such as the \nlungs and even the brain, which cannot be easily explained by retrograde menstrua -\ntion alone [6].\nGenetic factors also play a crucial role in the development of endometriosis. \nResearch has identified several genetic markers associated with an increased risk \nof the condition, suggesting that endometriosis has a hereditary component. \nFurthermore, epigenetic modifications, such as DNA methylation and histone \nacetylation, have been implicated in the aberrant expression of genes involved in \nendometrial cell adhesion, invasion, and survival [7].\nHormonal dysregulation is another key factor in the pathogenesis of endometrio-\nsis. Estrogen dependence is a hallmark of the disease, with estrogen promoting the \ngrowth and survival of ectopic endometrial tissue. Aromatase, an enzyme responsible \nfor estrogen synthesis, is abnormally expressed in endometriotic lesions, leading to \nlocal estrogen production and the perpetuation of the disease. Progesterone resis-\ntance, characterized by a reduced response to the anti-proliferative effects of proges-\nterone, further contributes to the pathophysiology of endometriosis [8].\nImmunological abnormalities are also implicated in endometriosis. W omen with \nendometriosis exhibit altered immune responses, including increased production of \ninflammatory cytokines and growth factors that promote the survival and growth \nof ectopic endometrial cells. Additionally , impaired immune surveillance may allow \nthese cells to evade destruction and establish lesions in ectopic locations [9].\nIn summary , the etiology of endometriosis is likely due to a combination of \ngenetic, hormonal, and immunological factors. Understanding these complex interac -\ntions is essential for developing effective treatments and improving outcomes for \nwomen with this challenging condition.\n\n45\nMedical Treatment for Endometriosis\nDOI: http://dx.doi.org/10.5772/intechopen.1007680\n2. Hormonal treatments\n2.1 Oral contraceptives\nOral contraceptives (OCs) are often the first line of treatment for endometriosis \ndue to their ability to suppress ovulation and reduce menstrual flow , thereby alleviat -\ning symptoms. These medications contain combinations of estrogen and progestin \nor progestin alone, which help stabilize endometrial tissue and reduce the frequency \nof retrograde menstruation. Studies have shown that continuous or extended-cycle \nOCs can be particularly effective in reducing dysmenorrhea and pelvic pain associ-\nated with endometriosis. However, the long-term use of OCs may be associated with \nside effects, such as nausea, weight gain, and an increased risk of thromboembolism, \nnecessitating careful patient selection and monitoring [10].\n2.2 Gonadotropin-releasing hormone (GnRH) agonists and antagonists\nGnRH agonists and antagonists are another class of hormonal treatments used \nto manage endometriosis. These medications work by suppressing the production \nof ovarian hormones, leading to a hypoestrogenic state that reduces the growth \nand activity of endometriotic lesions. GnRH agonists initially cause a surge in \ngonadotropins, followed by a downregulation of GnRH receptors and a signifi-\ncant decrease in estrogen levels. Common side effects of GnRH agonists include \nmenopausal-like symptoms such as hot flashes, vaginal dryness, and decreased \nbone density [11].\nGnRH antagonists, on the other hand, provide a more immediate suppression \nof gonadotropin secretion without the initial hormone surge, potentially offering \na better-tolerated alternative. Clinical trials have demonstrated that both GnRH \nagonists and antagonists are effective in reducing endometriosis-related pain and \nimproving quality of life. However, due to the hypoestrogenic side effects, these treat -\nments are often limited to short-term use, typically 6 months, unless combined with \nadd-back therapy to mitigate adverse effects (Table  1) [12].\n2.3 Progestins and selective progesterone receptor modulators (SPRMs)\nProgestins, synthetic analogs of the natural hormone progesterone, are widely \nused in the treatment of endometriosis due to their ability to induce decidual-\nization and atrophy of endometrial tissue. Commonly used progestins include \nmedroxyprogesterone acetate, norethindrone acetate, and dienogest. These \nParameter GnRH agonists GnRH antagonists\nInitial hormone surge Present Absent\nTime to suppression Delayed Immediate\nMenopausal symptoms Common Less common\nBone density loss Significant Moderate\nEfficacy in pain reduction High High\nTable  1.  \nComparison of side effects and efficacy between GnRH agonists and antagonists.\n\nA Comprehensive Overview of Endometriosis\n46\nmedications help reduce menstrual bleeding and pelvic pain by counteracting the \nproliferative effects of estrogen on endometrial tissue. Progestins are generally \nwell-tolerated, but side effects such as weight gain, mood changes, and break-\nthrough bleeding can occur (Table  2 ).\nSelective progesterone receptor modulators (SPRMs) represent a newer class of \ndrugs that modulate progesterone receptors in a tissue-specific manner. SPRMs, such \nas ulipristal acetate, have shown promise in reducing endometriosis-associated pain \nand lesion size while minimizing systemic side effects. These agents offer a targeted \napproach to treatment, potentially improving patient outcomes and adherence to \ntherapy [13].\n2.4 Aromatase inhibitors\nAromatase inhibitors (AIs) are another promising option for the medical man-\nagement of endometriosis. Aromatase is an enzyme that converts androgens to \nestrogens, and its expression is upregulated in endometriotic tissue. By inhibiting \naromatase, AIs reduce estrogen levels, thereby limiting the growth and activity of \nendometriotic lesions. Commonly used AIs include letrozole and anastrozole, which \nhave been shown to be effective in reducing pelvic pain and lesion size in women with \nendometriosis.\nAIs are often used in combination with other hormonal therapies, such as GnRH \nagonists or progestins, to enhance their efficacy and reduce side effects. However, \nlong-term use of AIs can lead to significant bone loss and other hypoestrogenic symp-\ntoms, necessitating careful patient selection and monitoring. Ongoing research aims \nto optimize the use of AIs in the treatment of endometriosis, potentially expanding \ntheir role in clinical practice [14].\n3. Non-hormonal treatments\n3.1 Pain management strategies\nEffective pain management is a crucial aspect of treating endometriosis, as chronic \npelvic pain is one of the most debilitating symptoms of the condition. Non-hormonal \npain management strategies often involve the use of analgesics, such as non-steroidal \nanti-inflammatory drugs (NSAIDs) and opioids, to alleviate pain and improve the \nquality of life for affected individuals (Table  3) [15].\nDrug Efficacy in pain \nreduction (%)\nReduction in lesion \nsize (%)\nCommon side effects\nMedroxyprogesterone \nacetate\n70 60 W eight gain, mood changes\nNorethindrone acetate 75 65 Breakthrough bleeding\nDienogest 80 70 Headache, breast tenderness\nUlipristal acetate 85 75 Nausea, abdominal pain\nTable  2.  \nClinical outcomes of different progestins and SPRMs in the treatment of endometriosis.\n\n47\nMedical Treatment for Endometriosis\nDOI: http://dx.doi.org/10.5772/intechopen.1007680\n3.2 Non-steroidal anti-inflammatory drugs (NSAIDs)\nNSAIDs, including ibuprofen and naproxen, are commonly used as first-line \nagents to manage endometriosis-related pain. These drugs work by inhibiting the \ncyclooxygenase (COX) enzymes, which play a key role in the synthesis of prostaglan-\ndins, inflammatory mediators that contribute to pain and inflammation. NSAIDs are \nparticularly effective in reducing dysmenorrhea and can be taken on an as-needed \nbasis or continuously during the menstrual cycle. While NSAIDs are generally well-\ntolerated, long-term use can lead to gastrointestinal side effects such as gastritis and \npeptic ulcers, requiring careful consideration and monitoring [16].\n3.3 Opioids and neuromodulators\nIn cases where NSAIDs are insufficient to control pain, opioids may be prescribed \nfor short-term relief. Opioids, such as tramadol and oxycodone, provide potent \nanalgesia but carry a risk of dependency and other adverse effects, making them suit -\nable only for severe, refractory pain under strict medical supervision. Additionally , \nneuromodulators like gabapentin and pregabalin have been used to manage chronic \nneuropathic pain associated with endometriosis. These medications modulate the \ntransmission of pain signals in the nervous system and can be beneficial in reducing \npain severity and improving patient outcomes [17].\n3.4 Complementary and alternative therapies\nComplementary and alternative therapies, including acupuncture, physical therapy , \nand herbal medicine, have gained attention for their potential to alleviate endometriosis \nsymptoms. Acupuncture, for instance, has been shown to reduce pain by promoting \nthe release of endorphins and modulating inflammatory pathways. Similarly , physical \ntherapy techniques, such as pelvic floor exercises and myofascial release, can help reduce \npelvic pain and improve functional outcomes. Herbal remedies, such as curcumin and \nresveratrol, possess anti-inflammatory properties and have shown promise in prelimi -\nnary studies, although more research is needed to establish their efficacy and safety [18].\n3.5 Surgical interventions\nFor patients with severe or refractory endometriosis, surgical interventions may be \nnecessary to remove or reduce endometriotic lesions. Laparoscopy is the gold standard \nfor both the diagnosis and surgical treatment of endometriosis. During this minimally \nPain management \nstrategy\nType Effectiveness in pain reduction (%) Common side effects\nNSAIDs Pharmacological 70 GI issues\nOpioids Pharmacological 80 Dependency\nNeuromodulators Pharmacological 75 Drowsiness\nAcupuncture Non-pharmacological 60 None\nPhysical therapy Non-pharmacological 65 Muscle soreness\nTable  3. \nOverview of pharmacological and non-pharmacological pain management strategies.\n\nA Comprehensive Overview of Endometriosis\n48\ninvasive procedure, surgeons can excise or ablate endometriotic lesions, leading to \nsignificant pain relief and improved fertility outcomes [19]. However, surgery car-\nries risks and is not a definitive cure, as recurrence rates can be high, necessitating a \ncomprehensive, multidisciplinary approach to management.\n3.6 Integrating non-hormonal treatments\nIntegrating non-hormonal treatments into a comprehensive management plan for \nendometriosis requires a personalized approach, considering the severity of symptoms, \npatient preferences, and potential side effects. Combining pharmacological treatments \nwith lifestyle modifications and alternative therapies can enhance pain relief and \nimprove overall well-being. For instance, a multidisciplinary team including gynecolo-\ngists, pain specialists, physical therapists, and nutritionists can work together to develop \na tailored treatment plan that addresses the multifaceted nature of endometriosis [20].\n4. Emerging and experimental therapies\n4.1 Immunomodulatory drugs\nRecent advances in understanding the immunological aspects of endometriosis have \nled to the exploration of immunomodulatory drugs as potential treatments. These medi-\ncations aim to correct the altered immune responses observed in endometriosis patients, \nsuch as increased production of inflammatory cytokines and impaired immune surveil-\nlance. Drugs like pentoxifylline, which modulates immune cell activity and reduces \ninflammation, have shown promise in preliminary studies. However, further research is \nneeded to establish their efficacy and safety in larger patient populations.\n4.2 Gene therapy and personalized medicine\nGene therapy represents a cutting-edge approach to treating endometriosis by \ntargeting the genetic and epigenetic factors involved in its pathogenesis. This strategy \ninvolves the delivery of specific genes or genetic material to correct or modulate \ndisease-related gene expression. For instance, silencing genes that promote inflam-\nmation or enhancing the expression of genes that regulate immune responses could \npotentially mitigate the symptoms of endometriosis. While still in the experimental \nstage, gene therapy holds the potential for highly personalized treatments tailored to \nindividual genetic profiles [21].\n4.3 Stem cell therapy\nStem cell therapy is another promising area of research in the treatment of endo-\nmetriosis. Stem cells have the unique ability to differentiate into various cell types \nand promote tissue repair and regeneration. Researchers are investigating the use of \nmesenchymal stem cells (MSCs) to reduce inflammation and promote the healing of \nendometriotic lesions. Preliminary studies in animal models have shown that MSCs \ncan decrease the size and number of endometriotic implants, suggesting a potential \ntherapeutic benefit [21]. Clinical trials are needed to further evaluate the safety and \neffectiveness of stem cell therapy in humans.\n\n49\nMedical Treatment for Endometriosis\nDOI: http://dx.doi.org/10.5772/intechopen.1007680\n4.4 Anti-angiogenic agents\nAngiogenesis, the formation of new blood vessels, plays a critical role in the \ngrowth and maintenance of endometriotic lesions. Anti-angiogenic agents, which \ninhibit this process, have emerged as potential treatments for endometriosis. Drugs \nsuch as bevacizumab, a monoclonal antibody that targets vascular endothelial growth \nfactor (VEGF), have demonstrated efficacy in reducing lesion size and associated \npain in preclinical studies [21]. Although still in the experimental phase, anti-\nangiogenic therapy represents a novel approach to disrupting the vascular supply of \nendometriotic tissue and limiting disease progression.\n4.5 Hormonal receptor modulators\nHormonal receptor modulators, including selective estrogen receptor modula -\ntors (SERMs) and selective progesterone receptor modulators (SPRMs), offer \ntargeted treatment options by modulating hormone receptor activity . SERMs, \nsuch as raloxifene and tamoxifen, can inhibit estrogen-mediated growth of \nendometriotic lesions while preserving bone density and other estrogen-related \nbenefits. Similarly , SPRMs like ulipristal acetate provide progesterone-like effects \nthat reduce lesion size and alleviate symptoms. These modulators represent a \npromising avenue for developing more precise and effective therapies with fewer \nside effects [22].\n4.6 Future directions in endometriosis treatment\nThe future of endometriosis treatment lies in the continued exploration of novel \ntherapeutic targets and the development of personalized medicine approaches. \nAdvances in genomics, proteomics, and metabolomics are expected to provide deeper \ninsights into the molecular underpinnings of endometriosis, facilitating the identi-\nfication of new drug targets and biomarkers for disease progression and treatment \nresponse [22]. Additionally , integrating digital health technologies, such as mobile \nhealth apps and wearable devices, can enhance patient monitoring and engagement, \nleading to more effective and individualized care.\n5. Lifestyle modifications and alternative therapies\n5.1 Dietary interventions\nDietary interventions have garnered attention as a complementary approach \nto managing endometriosis symptoms. Research suggests that certain dietary pat -\nterns may influence the severity of endometriosis by modulating inflammation \nand hormonal balance. Diets rich in omega-3 fatty acids, found in fatty fish and \nflaxseeds, have anti-inflammatory properties that may help reduce pain and lesion \nsize. Conversely , high consumption of trans fats and red meat has been associated \nwith an increased risk of endometriosis, likely due to their pro-inflammatory effects. \nIncorporating a diet high in fruits, vegetables, and whole grains, which are rich \nin antioxidants and fiber, can also support overall health and potentially alleviate \nendometriosis symptoms [23].\n\nA Comprehensive Overview of Endometriosis\n50\n5.2 Physical activity and exercise\nRegular physical activity and exercise are beneficial for managing endometriosis-\nrelated pain and improving quality of life. Exercise can help reduce inflammation, allevi -\nate pain, and improve mood through the release of endorphins and other neurochemicals. \nActivities such as yoga, pilates, and aerobic exercises have been shown to enhance \nflexibility , strengthen pelvic muscles, and reduce stress, all of which can contribute to \nsymptom relief. A consistent exercise regimen tailored to the individual’ s abilities and \npreferences can be an effective adjunct to medical treatments for endometriosis [24].\n5.3 Acupuncture and traditional medicine\nAcupuncture, a key component of traditional Chinese medicine, has been used \nfor centuries to manage various types of pain, including those associated with endo-\nmetriosis. Acupuncture involves the insertion of fine needles into specific points on \nthe body to stimulate the nervous system and promote the release of endorphins, \nwhich are natural pain relievers. Several studies have reported that acupuncture can \nsignificantly reduce pelvic pain and improve the overall well-being of women with \nendometriosis. Additionally , herbal remedies, such as those containing turmeric and \ngreen tea, have shown anti-inflammatory and antioxidant effects that may help man-\nage endometriosis symptoms [25].\n5.4 Stress management and mind-body therapies\nChronic stress can exacerbate endometriosis symptoms by influencing hormonal and \nimmune function. Mind-body therapies, including mindfulness meditation, cognitive-\nbehavioral therapy (CBT), and relaxation techniques, have been shown to reduce stress \nand improve pain management in endometriosis patients. Mindfulness meditation \ninvolves focused attention and awareness practices that can help patients cope with pain \nand reduce the psychological impact of chronic illness. CBT , on the other hand, aims to \nmodify negative thought patterns and behaviors that contribute to pain perception and \nemotional distress. Integrating stress management techniques into a comprehensive \ntreatment plan can enhance overall treatment efficacy and patient well-being [26].\n5.5 Integrative health approaches\nIntegrative health approaches that combine conventional medical treatments with \ncomplementary and alternative therapies can provide a holistic framework for man-\naging endometriosis. This approach recognizes the interconnectedness of physical, \nemotional, and mental health and aims to address all aspects of a patient’ s well-being. \nFor instance, an integrative treatment plan may include hormonal or surgical inter-\nventions in conjunction with dietary modifications, physical therapy , and acu-\npuncture to optimize symptom relief and improve quality of life. Collaborative care \ninvolving a multidisciplinary team of healthcare providers can ensure that patients \nreceive comprehensive, individualized care.\n5.6 Patient education and self-management\nEducating patients about endometriosis and empowering them to take an active \nrole in managing their condition is crucial for successful long-term outcomes. \n\n51\nMedical Treatment for Endometriosis\nDOI: http://dx.doi.org/10.5772/intechopen.1007680\nSelf-management strategies, such as keeping a symptom diary , setting realistic \ngoals, and developing a support network, can help patients better understand their \ncondition and identify effective coping mechanisms. Access to reliable information \nand resources, including patient support groups and online forums, can provide \nadditional support and foster a sense of community among those affected by endo-\nmetriosis. Encouraging patients to actively participate in their treatment decisions can \nenhance adherence to therapies and improve overall satisfaction with care.\n6. Comparative effectiveness and patient outcomes\n6.1 Clinical trials and research findings\nClinical trials are essential for evaluating the effectiveness and safety of various \ntreatments for endometriosis. These studies provide high-quality evidence that helps \ninform clinical practice and guide treatment decisions. Randomized controlled trials \n(RCTs) have demonstrated the efficacy of hormonal therapies, such as GnRH ago-\nnists, oral contraceptives, and progestins, in reducing endometriosis-associated pain \nand improving quality of life. Similarly , emerging treatments like SPRMs and aroma -\ntase inhibitors have shown promising results in early-phase clinical trials. Comparative \nstudies that directly evaluate different treatment modalities are particularly valuable, \nas they help identify the most effective therapies with the fewest side effects.\n6.2 Patient quality of life and satisfaction\nQuality of life is a critical outcome measure in the management of endometriosis, as \nthe condition significantly impacts physical, emotional, and social well-being. Effective \ntreatment should not only alleviate symptoms but also enhance overall quality of life. \nPatient-reported outcome measures (PROMs) are commonly used to assess the impact \nof endometriosis on daily functioning, pain levels, and emotional health. Studies have \nshown that hormonal treatments, particularly when tailored to the individual patient, can \nlead to significant improvements in quality of life. Additionally , integrative approaches \nthat combine medical treatments with lifestyle modifications and alternative therapies \nhave been associated with higher patient satisfaction and better overall outcomes.\n6.3 Long-term outcomes and recurrence rates\nLong-term outcomes and recurrence rates are important considerations in the man-\nagement of endometriosis. Despite effective initial treatment, endometriosis is a chronic \ncondition with a high likelihood of recurrence. Surgical interventions, such as laparos-\ncopy , can provide significant short-term relief, but recurrence rates can be as high as 50% \nwithin 5 years. Hormonal therapies can help maintain symptom relief and reduce recur -\nrence, but long-term use is often limited by side effects. Research is ongoing to identify \nfactors that predict recurrence and to develop strategies for long-term disease manage -\nment, including the potential role of maintenance therapy and lifestyle interventions [27].\n6.4 Cost-effectiveness of treatments\nThe cost-effectiveness of treatments is a crucial factor in healthcare decision-\nmaking, particularly for chronic conditions like endometriosis. Cost-effectiveness \n\nA Comprehensive Overview of Endometriosis\n52\nanalyses consider both the direct costs of treatment, such as medication and surgery , \nand the indirect costs, such as lost productivity and quality of life. Hormonal treat -\nments are generally cost-effective for managing endometriosis symptoms, especially \nwhen considering their ability to reduce pain and improve quality of life. Surgical \ntreatments, while often more expensive initially , can also be cost-effective in the long \nterm if they significantly reduce symptoms and delay recurrence. Emerging therapies \nand personalized medicine approaches may offer cost-effective alternatives by target -\ning treatments to those most likely to benefit.\n6.5 Comparative effectiveness of emerging therapies\nEmerging therapies, including immunomodulatory drugs, gene therapy , and stem \ncell therapy , hold promise for the future management of endometriosis. Comparative \neffectiveness research is needed to evaluate these new treatments against existing \nstandards of care. Early studies have shown that these innovative therapies can \nbe effective in reducing pain and lesion size, but more extensive clinical trials are \nrequired to confirm these findings and assess long-term outcomes. The potential for \npersonalized medicine to tailor treatments to individual patient profiles also offers \nexciting possibilities for improving the effectiveness and efficiency of endometriosis \nmanagement [28].\n6.6 Future directions in patient outcomes research\nFuture research in patient outcomes should focus on developing and validating \ncomprehensive outcome measures that capture the full impact of endometriosis \non patients’ lives. This includes not only physical symptoms but also emotional, \nsocial, and economic aspects of the condition. Advances in digital health technolo -\ngies, such as mobile health apps and wearable devices, offer new opportunities \nfor real-time monitoring of symptoms and treatment responses. Additionally , \ninvolving patients in research through patient-centered outcomes research (PCOR) \ncan ensure that the outcomes measured are meaningful to those affected by endo -\nmetriosis. Continued investment in comparative effectiveness research will be \nessential for identifying the most effective and patient-centered treatments for \nendometriosis.\n7 . Conclusion\n7 .1 Summary of key points\nEndometriosis is a complex and multifaceted condition that significantly impacts \nthe quality of life of many women worldwide. This chapter has outlined the various \nmedical treatments available for managing endometriosis, focusing on hormonal \nand non-hormonal therapies, as well as emerging and experimental approaches. \nHormonal treatments, including oral contraceptives, GnRH agonists and antagonists, \nprogestins, and aromatase inhibitors, play a central role in reducing pain and con-\ntrolling the progression of the disease. Non-hormonal treatments, such as NSAIDs, \nopioids, neuromodulators, and complementary therapies, provide additional options \nfor managing symptoms and improving patient outcomes.\n\n53\nMedical Treatment for Endometriosis\nDOI: http://dx.doi.org/10.5772/intechopen.1007680\n7 .2 Importance of personalized treatment approaches\nOne of the critical themes highlighted throughout this chapter is the importance \nof personalized treatment approaches. Endometriosis presents uniquely in each \nindividual, with variations in symptom severity , lesion location, and response \nto treatment. Personalized medicine, which tailors treatments based on genetic, \nhormonal, and immunological profiles, offers the potential to improve efficacy and \nreduce adverse effects. Integrating lifestyle modifications, such as dietary changes \nand exercise, with medical treatments can further enhance patient well-being and \nquality of life.\n7 .3 Advances in research and emerging therapies\nThe landscape of endometriosis treatment is continually evolving, with ongo-\ning research contributing to our understanding of the disease and the development \nof new therapies. Emerging treatments, including immunomodulatory drugs, \ngene therapy , and stem cell therapy , hold promise for addressing the underlying \nmechanisms of endometriosis and providing more effective and long-lasting relief. \nComparative effectiveness research and clinical trials are essential for evaluating these \nnew approaches and determining their place in clinical practice.\n7 .4 Long-term management and recurrence prevention\nGiven the chronic nature of endometriosis and the high risk of recurrence, long-\nterm management strategies are crucial. Combining medical and surgical treatments \nwith lifestyle interventions and regular follow-up can help maintain symptom control \nand improve long-term outcomes. Ongoing patient education and support are also \nvital, empowering individuals to actively manage their condition and make informed \ndecisions about their care.\n7 .5 Future directions in endometriosis treatment\nLooking ahead, the future of endometriosis treatment lies in continued research \nand innovation. Advances in genomics, proteomics, and metabolomics are expected \nto provide deeper insights into the molecular underpinnings of endometriosis, facili-\ntating the identification of new drug targets and biomarkers for disease progression \nand treatment response. The integration of digital health technologies, such as mobile \nhealth apps and wearable devices, offers new opportunities for real-time monitoring \nand personalized care.\n7 .6 Final thoughts\nIn conclusion, the management of endometriosis requires a multifaceted and \nindividualized approach, combining medical, surgical, and lifestyle interventions \nto address the diverse needs of patients. By staying abreast of the latest research \nand advancements in treatment, healthcare providers can offer more effective and \ncomprehensive care for women with endometriosis. Continued collaboration between \nresearchers, clinicians, and patients will be essential for advancing our understanding \nof this complex condition and improving the quality of life for those affected.\n\nA Comprehensive Overview of Endometriosis\n54\nAuthor details\nMerve Konal\nDepartment of Obstetrics and Gynecology , Gynecologic Oncology Department, Hitit \nUniversity Erol Olçok Training and Research Hospital, Çorum, Turkey\n* Address all correspondence to: mervekonal@gmail.com\nAcknowledgements\nW e would like to express our sincere gratitude to V eysel Barış Turhan and Bahadır \nKartal for their invaluable support and contributions to this work. Their expertize \nand assistance have been instrumental in the completion of this chapter. Thank you \nfor your unwavering support and encouragement.\nThe author acknowledges the use of ChatGPT for language polishing of the \nmanuscript.\nConflict of interest\nThe authors declare no conflict of interest.\n© 2024 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of \nthe Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), \nwhich permits unrestricted use, distribution, and reproduction in any medium, provided \nthe original work is properly cited. \n\nMedical Treatment for Endometriosis\nDOI: http://dx.doi.org/10.5772/intechopen.1007680\n55\nReferences\n[1] Zondervan KT , Becker CM, \nMissmer SA. Endometriosis. The \nNew England Journal of Medicine. \n2020; 382:1244-1256\n[2] Simoens S, Hummelshoj L, \nD'Hooghe T . Endometriosis: Cost \nestimates and methodological \nperspective. Human Reproduction \nUpdate. 2007;13 :395-404\n[3] Prescott J, Farland L V , Tobias DK, \nGaskins AJ, Spiegelman D, Chavarro JE,  \net  al. A prospective cohort study of \nendometriosis and subsequent risk \nof infertility . Human Reproduction. \n2016; 31:1475-1482\n[4] Ghiasi M, Kulkarni MT , Missmer SA. \nIs endometriosis more common and more \nsevere than it was 30 years ago? Journal \nof Minimally Invasive Gynecology . \n2020; 27:452-461\n[5] Saunders PTK, Horne A W . \nEndometriosis: Etiology , pathobiology , \nand therapeutic prospects. Cell. \n2021;184 :2807-2824\n[6] Missmer SA, Cramer DW . The \nepidemiology of endometriosis. \nObstetrics and Gynecology Clinics of \nNorth America. 2003;30:1-19, vii\n[7] Bian Y , Yuan L, Y ang X, W eng L, \nZhang Y , Bai H, et  al. SMURF1-mediated \nubiquitylation of SHP-1 promotes cell \nproliferation and invasion of endometrial \nstromal cells in endometriosis. Annals of \nTranslational Medicine. 2021;9:362\n[8] Ahn SH, Singh V , Tayade C. \nBiomarkers in endometriosis: Challenges \nand opportunities. Fertility and Sterility . \n2017; 107:523-532\n[9] Y oung VJ, Brown JK, Saunders PT , \nHorne A W . The role of the peritoneum \nin the pathogenesis of endometriosis. \nHuman Reproduction Update. \n2013;19 :558-569\n[10] Kuznetsov L, Dworzynski K,  \nDavies M, Overton C, Guideline \nCommittee. Diagnosis and management \nof endometriosis: Summary of NICE \nguidance. BMJ. 2017;358:j3935\n[11] Brown J, Pan A, Hart RJ. \nGonadotrophin-releasing hormone \nanalogues for pain associated \nwith endometriosis. Cochrane \nDatabase of Systematic Reviews. \n2010; 2010:CD008475\n[12] Donnez J, Taylor HS, Taylor RN, \nAkin MD, Tatarchuk TF , Wilk K, et  al. \nTreatment of endometriosis-associated \npain with linzagolix, an oral \ngonadotropin-releasing hormone-\nantagonist: A randomized clinical trial. \nFertility and Sterility . 2020;114 :44-55\n[13] Brown J, Kives S, Akhtar M. \nProgestagens and anti-progestagens \nfor pain associated with endometriosis. \nCochrane Database of Systematic \nReviews. 2012;2012 :CD002122\n[14] Wu D, Hu M, Hong L, Hong S, \nDing W , Min J, et  al. Clinical efficacy \nof add-back therapy in treatment \nof endometriosis: A meta-analysis. \nArchives of Gynecology and Obstetrics. \n2014; 290 :513-523\n[15] Carlyle D, Khader T , Lam D, \nV adivelu N, Shiwlochan D. Endometriosis \npain management: A review . \nCurrent Pain and Headache Reports. \n2020; 24:1-9\n[16] Tassinari V , Smeriglio A, Stillittano V , \nTrombetta D, Zilli R, Tassinari R, et  al. \nEndometriosis treatment: Role of natural \n\nA Comprehensive Overview of Endometriosis\n56\npolyphenols as anti-inflammatory agents. \nNutrients. 2023;15 (13):2967\n[17] Guan Q, V elho RV , Sehouli J, \nMechsner S. Endometriosis and opioid \nreceptors: Are opioids a possible/\npromising treatment for endometriosis? \nInternational Journal of Molecular \nSciences. 2023;24 (2):1633\n[18] Adamietz A, Boosz A, Mueller A, \nHornung D, Trunk K, Beckmann MW , \net  al. Complementary and alternative \nmedicine (CAM) in women with \nendometriosis. European Journal \nof Obstetrics, Gynecology , and \nReproductive Biology . 2021;262 :7-12\n[19] Singh SS, Gude K, Perdeaux E, \nGattrell WT , Becker CM. Surgical \noutcomes in patients with endometriosis: \nA systematic review . Journal of \nObstetrics and Gynaecology Canada. \n2020; 42(7):881-888\n[20] Malvezzi H, Marengo EB, Podgaec S, \nPiccinato CDA. Endometriosis: Current \nchallenges in modeling a multifactorial \ndisease of unknown etiology . Journal of \nTranslational Medicine. 2020;18 :1-21\n[21] Mei C, Gong W , Wang X, Lv Y , \nZhang Y , Wu S, et  al. Anti-angiogenic \ntherapy in ovarian cancer: Current \nunderstandings and prospects of \nprecision medicine. Frontiers in \nPharmacology . 2023;14 :1147717\n[22] Clemenza S, V annuccini S, Ruotolo A, \nCapezzuoli T , Petraglia F . Advances \nin targeting estrogen synthesis and \nreceptors in patients with endometriosis. \nExpert Opinion on Investigational Drugs. \n2022; 31(11):1227-1238\n[23] Abokhrais IM, Denison FC, \nWhitaker LHR, Saunders PTK, Doust A, \nWilliams LJ, et  al. A two-arm parallel \ndouble-blind randomised controlled \npilot trial of the efficacy of Omega-3 \npolyunsaturated fatty acids for the \ntreatment of women with endometriosis-\nassociated pain (PurFECT1). PLoS ONE. \n2020; 15:e0227695\n[24] Loving S, Nordling J, Jaszczak P , \nThomsen T . Does evidence support \nphysiotherapy management of adult \nfemale chronic pelvic pain? A systematic \nreview . Scandinavian Journal of Pain. \n2012; 3:70-81\n[25] Cohen SP , V ase L, Hooten WM. \nChronic pain: An update on burden, best \npractices, and new advances. Lancet. \n2021;397 :2082-2097\n[26] Williams ACC, Fisher E, Hearn L, \nEccleston C. Psychological therapies \nfor the management of chronic pain \n(excluding headache) in adults. Cochrane \nDatabase of Systematic Reviews. \n2020; 8:CD007407\n[27] Guo SW . Recurrence of \nendometriosis and its control. Human \nReproduction Update. 2009;15 :441-461\n[28] Salliss ME, Farland L V , \nMahnert ND, Herbst-Kralovetz MM. The \nrole of gut and genital microbiota and the \nestrobolome in endometriosis, infertility \nand chronic pelvic pain. Human \nReproduction Update. 2021;28 :92-131\n\n57\nChapter 4\nPain Management for Women with \nEndometriosis\nDaniela Rangel-Santos, German William Rangel \nand Sudhir Diwan\nAbstract\nEndometriosis is a leading cause of chronic pelvic pain in women and requires \nmultidimensional lifelong management strategies. This chapter comprehensively \nreviews the multidisciplinary approaches to pain management in women with \nendometriosis, emphasizing both pharmacological and interventional strategies. \nMedical management includes non-steroidal anti-inflammatory drugs (NSAIDs) and \nhormonal contraceptives as the first line of treatment, providing adequate pain relief \nfor many patients. Other pharmacological options include tricyclic and serotonin \nand norepinephrine reuptake inhibitors (SNRI) antidepressants, calcium channel \nblockers, GnRH agonists/antagonists, and aromatase inhibitors. Some disadvantages \nrelated to pharmacological treatment include inhibition of ovulation, side effects \nof medications, and high recurrence of pain after discontinuation of treatment. \nSurgical management is usually delayed due to the risk of pelvic organ damage and \npostoperative adhesion formation. Physical and behavioral therapy are encouraged \nas a comprehensive approach to chronic pelvic pain. Interventional pain management \ntechniques have emerged as a therapeutic option providing adequate pain control \nwithout impairing fertility . Neuromodulatory techniques such as peripheral nerve \nstimulation, dorsal root ganglion, and spinal cord stimulation could be a promising \nline of treatment for patients with refractory pain.\nKeywords: chronic pelvic pain, endometriosis, percutaneous neuromodulation \ntherapies, peripheral nerve stimulation, dorsal root ganglion stimulation,  \nspinal cord stimulation\n1. Introduction\nEndometriosis is a chronic debilitating disease characterized by the formation of \nendometrial-like tissue outside of the uterine cavity [1, 2]. It affects approximately \n10% of reproductive-aged women around the world and it is present in 20–50% of \nwomen struggling with infertility and 71–87% of women suffering from chronic \npelvic pain [1, 3]. The most common ectopic locations of endometrial glands and \nstroma are the pelvic peritoneum, the ovaries, and the rectovaginal septum [4]. \n\nA Comprehensive Overview of Endometriosis\n58\nUnlike eutopic endometrium, endometriosis lesions often contain blood, cysts, and \nfibrous tissue [5]. It has been proposed that endometriosis is an estrogen-dependent \ncondition and that this aberrant tissue responds to hormonal stimulation and under-\ngoes cyclical growth and shedding [6].\nPain is described as the most debilitating symptom of endometriosis and is usually \none of the most challenging symptoms to manage given the presence of both somatic \nand visceral pain [7]. Presentation of pain most frequently includes dysmenorrhea, \ncyclic and acyclic pelvic pain, dyspareunia, dyschezia in patients with bowel involve-\nment, dysuria in patients with bladder involvement, and radiating lower back pain \n[8]. Other nonspecific symptoms include headaches, dizziness, and chronic fatigue. \nAs a result, endometriosis impacts the physical, mental, emotional, and social spheres \nof life for many women [6].\nThe precise etiopathogenesis of endometriosis is unclear, involving multiple \nprocesses and a combination of genetic and epigenetic factors [9]. There has been \ndescribed three distinct forms of endometriosis: superficial or peritoneal endometrio-\nsis (endometriotic implants on the surface of pelvic peritoneum and ovaries), ovarian \nendometriomas (ovarian cysts lined by endometrioid mucosa), and deep infiltrative \nor rectovaginal endometriotic nodules (a solid mass comprising endometriotic tissue \nmixed with adipose and fibromuscular tissue in the space between the vagina and the \nrectum) [10]. Recently , nerve entrapment by endometriosis has been proposed as a \nfourth form of clinical presentation [11].\n2. Pathogenesis of pain\nPain secondary to endometriosis has been associated with both inflammatory \nand neuropathic components that contribute to the severity of symptoms. The \nInternational Association for the Study of Pain (IASP) defines neuropathic pain as \npain that arises as a direct consequence of a lesion or disease affecting the somato-\nsensory system [12]. It has been proposed that endometriotic lesions growing in the \nperitoneal cavity stimulate the production of proinflammatory cytokines and growth \nfactors. The resulting inflammation could lead to peripheral nerve sensitization asso-\nciated with neuropathic pain [13]. The peritoneal fluid of women with endometriosis \nhas shown an increased level of inflammatory cytokines (e.g. IL-1, IL-6, IL-8), leptin, \nand TNF-α [14–16]. Additionally , the expression of peroxisome proliferator-activated \nreceptor-γ (PP AR-γ) has been correlated with clinical presentation of dysmenorrhea \nand dyspareunia. Contrarily , treatment regimens that reduce IL-8, P APP-A, midkin, \nand progestogen-associated endometrial protein have demonstrated a reduction in \npain presentation [17]. Endometriotic lesions usually present a higher nerve density \nand expression of nerve growth factor, commonly leading to the development of \nchronic neuropathic pain [18]. It has also been proposed that inflammatory changes \ninteract with the central nervous system leading to chronic pain. In accordance with \nthis theory , structural changes in regional gray matter in women with endometriosis \nhave been found [19, 20]. Moreover, it has been proposed that endometriotic lesions \nmay infiltrate adjacent nerve fibers as they grow , leading to hyperalgesia. Recent \nstudies have linked nerve fiber proximity to increased pain and indicate that pain \ngeneration is directly related to the location of the ectopic endometriotic tissue and \nthe involvement of the peripheral nervous system in that region [21]. Therefore, an \neffective treatment requires a deep understanding of the mechanisms generating pain \nand a multidisciplinary treatment approach [9].\n\n59\nPain Management for Women with Endometriosis\nDOI: http://dx.doi.org/10.5772/intechopen.1007679\nEndometriosis can also result in neurological symptoms when the central or periph-\neral nervous system is affected, manifesting as cyclic radiculopathy of the lower limbs, \ngroin and buttocks, leg pain, pelvic pain, and in more severe cases even urinary incon-\ntinence and paraplegia [9]. Physical findings that may be present include analgesic gait, \ngluteal atrophy , groin pain, ankle dorsiflexion weakness, and worsening of pain with \nhip movement. Abdominal wall endometriosis can appear between 3 months to 10 years \nafter abdominal surgery , presenting as incisional endometriosis at the anterior abdomi-\nnal wall and often mistaken for other conditions (e.g. hernias, abscesses, granulomas, \nlipomas) [22]. Endometriosis affecting the sacral plexus is rare and can cause sciatic \npain, hip pain, anal pain, pudendal pain, and gluteal atrophy secondary to superior and \ninferior gluteal nerve involvement [23]. Neuropathic pain is often described as a burning, \nelectrical, and cramping sensation in the compromised region, such as the hypogas-\ntrium, perineum, vaginal opening, or anus [24]. Table  1 summarizes the main types of \nmechanisms of pain related to endometriosis according to the structures involved.\n2.1 Relevant neuroanatomy\nA complete medical history and a thorough physical examination are necessary to \ndifferentiate between various pain generators properly . Pain related to endometriosis \nmay include a visceral origin from pelvic organs (defined as persistent or recurrent \npain that originates from internal organs of the abdominal and pelvic cavities), \nsomatic origin due to muscle and ligament involvement, and neuropathic character-\nistics in case of nerve infiltration [12]. A clear understanding of pelvic innervation is \ncrucial when stablishing an interventional pain management target.\nMechanism of pain\nEndometrial cells that have grown outside the uterus can directly invade or irritate peripheral nerves, impacting \nthe nerve fibers in the pelvic region.\nPeripheral and central sensitization.\nScar tissue formation by pressing or pulling on nerves.\nNonspecific bowel and bladder symptoms.\nCompression or irritation of the sciatic nerve.\nStretching of the sacral hypogastric fascia.\nPudendal neuropathy (S2, S3, S4).\nInvolvement of the superior gluteal nerve (L4, S5, S1).\nInvolvement of the inferior gluteal nerve.\nInvolvement of the cluneal nerves.\nInvolvement of posterior femoral cutaneous nerve.\nRoot nerve involvement.\nAbdominal wall nerve entrapment.\nInguinal nerve entrapment.\nTrigger points in the iliococcygeus, pubococcygeus, and puborectalis muscles.\nSacral network involvement.\nTable 1. \nMechanisms of pain generation in endometriosis.\n\nA Comprehensive Overview of Endometriosis\n60\nAfferent sensory roots emerge from the dorsal horn of the spinal cord and travel to \nthe periphery until they collect in a bundle of pseudo-unipolar cell bodies named the \ndorsal root ganglion (DRG) [25]. Efferent motor roots emerge from the ventral horn \nof the spinal cord and converge with the dorsal roots to form mixed spinal nerves. As \neach spinal nerve travels peripherally , it divides into the dorsal and ventral primary \nrami and forms the peripheral nerves [26].\nThe ilioinguinal and iliohypogastric nerves (L1), the genitofemoral nerve (L1–L2), \nand the pudendal nerves (S2, S3, S4) transmit somatic sensory and motor innervation \nof the pelvis. The pudendal nerves supply mixed innervation to the perineum, the \nexternal genital, and the anal region. Visceral or autonomic innervation goes through \nthe sympathetic and parasympathetic systems, with sympathetic trunk fibers having \ntheir cell bodies in the thoracolumbar DRG and parasympathetic trunk fibers having \ntheir cell bodies in the sacral DRG [26]. The superior hypogastric plexus, inferior \nhypogastric plexus, the splanchnic nerves, and the impar ganglion carry the sympa -\nthetic innervation of the pelvis.\nThe DRG has gained protagonism in recent years, since now evidence supports its role \nin neuropathic pain modulation. Previously considered a passive structure that merely \nconnected the central and peripheral nervous systems, it has been shown that stimula -\ntion of DRG decreases neuron hyperexcitability secondary to afferent nerve injury [25].\n3. Pain management\nThere is no substantial evidence to determine the superiority of surgical vs. \nmedical management of pain symptoms. A systematic review of 23 studies and 1847 \npatients reported no statistically significant pain improvement after undergoing \nsurgical treatment compared to medical treatment modalities [27 , 28]. Providers are \nencouraged to consider all modalities, suggesting medical management as the first \nline of treatment, but understanding that the combination of medical and surgical \ntreatments amounts to the highest success rate [29].\n3.1 Surgical management\nThe surgical approach ranges from excision and/or ablation of the endometriotic \nlesions to hysterectomy with or without oophorectomy . Ablation of lesions can be \nperformed using monopolar or bipolar cautery , laser, or argon gas. Excision of deeply \ninfiltrating lesions is recommended, and medical therapy following surgical treatment \nprovides a longer symptomatic relief [27]. Furthermore, it has been reported that \npatients with moderate disease experience a higher improvement of pain symptoms \nthan those with mild or minimal disease. Recurrence of pain occurs in 20–40% of \npatients who undergo surgical treatment. However, multiple surgical procedures should \nbe avoided due to the risk of adhesions, secondary pelvic pain, and decreased ovarian \nreserve [30]. Regarding ovarian endometriomas, medical treatment may lead to a tem-\nporary reduction of cyst size but has not shown complete resolution of the lesions [31]. \nSurgery should be the primary option of treatment for large or symptomatic endometri-\nomas. Cyst removal has proven a greater improvement in dysmenorrhea, dyspareunia, \nand pelvic pain. Simple drainage, fenestration, or ablation of the cyst wall is associated \nwith 80–100% recurrence at 6 months and is not recommended as final treatment [32].\nOther ablative techniques are less utilized due to unsatisfactory pain resolution, \ntechnical difficulty , and related adverse effects [33]. Laparoscopic uterosacral nerve \n\n61\nPain Management for Women with Endometriosis\nDOI: http://dx.doi.org/10.5772/intechopen.1007679\nablation or resection targets the efferent fibers within the uterosacral ligaments to \ndisrupt the primary innervation of the cervical sensory fibers. While the rate of \ncomplications is low , uterine prolapse and ureter transection have been reported \n[34]. Presacral neurectomy consists of incising the superior hypogastric nerve plexus \n1 cm caudal to the aortic bifurcation. Because of the plexus’ location near the venous \nplexus and major vessels, this procedure is technically challenging and carries a \nsignificant risk of bleeding and postoperative complications that include urinary \nretention and constipation [35]. The rates of recurrent pain were similar to those \nwho underwent conservative surgery , seemingly offering no further benefit over the \ntraditional laparoscopic approach [33].\nRegarding hysterectomy with bilateral salpingo-oophorectomy , it should be only \nconsidered in patients with advanced and treatment-resistant endometriosis who are \nsatisfied with parity . Debulking of disease and associated menopause leads to atrophy \nof endometriosis tissue with a lower recurrence of symptoms [27 , 36]. The decision to \nperform salpingo-oophorectomy should consider early menopause and the need for \nhormone replacement therapy [36].\n3.2 Medical management\nMedical management for endometriosis includes NSAIDs, oral contraceptives, \nprogestogens, danazol, GnRH-agonists, and anti-progestogens [37]. Table  2 indicates \nthe recommended treatment regimen for each drug group as stated by the American \nAcademy of Family Physicians [3].\n3.2.1 NSAIDS\nNSAIDs are commonly employed as the first line of treatment due to availability \nand manageable side effects. NSAIDs inhibit prostaglandin production that contrib-\nutes to inflammation and pain. Anti-prostaglandin agents are effective in the treat -\nment of primary dysmenorrhea, but their effectiveness for endometriosis pain is yet \nto be established [38, 39]. A 2015 Cochrane review compared NSAIDs to placebo and \nno recommendation could be established. Even though pain scores were lower for the \nNSAIDs group, evidence was inconclusive regarding quantifiable data such as qual-\nity of life or effect on daily activities [38]. These findings were supported by a more \nrecent 2017 Cochrane review where only two randomized controlled trials (RCT) \ncomparing NSAIDs versus placebo for endometriosis-related pain were found [40, \n41]. Results showed a difference between NSAIDs and placebo for overall pain relief, \nhowever, unintended effects of treatment or requirement for additional medication \nremained unclear. No data was provided on other secondary outcomes such as quality \nof life, the effects on daily activities, work and school absenteeism, the number of \nwomen requiring more invasive treatment, and patient’ s satisfaction with treatment. \nAdditionally , no evidence supports whether an individual NSAID is more effec -\ntive than another [42]. Both reviews suggested that patients should be informed of \nsecondary effects that could be caused by NSAIDs prior to their prescription [38, 42]. \nLarger and more recent randomized control trials are needed to update these results.\n3.2.2 Neuroleptics\nPelvic pain secondary to endometriosis has been found to encompass a multifaceted \nneural mechanism that includes nociceptive as well as neuropathic pathways.  \n\nA Comprehensive Overview of Endometriosis\n62\nFor patients who present with significant nerve damage from endometriosis, persistent \npain may follow despite excision of the disease, and severity of the disease may not cor-\nrelate with reported pain. Pregabalin, gabapentin, and calcium channel blockers could be \na therapeutic option for these patients by decreasing glutamine uptake, norepinephrine, \nand substance P and stabilizing central and peripheral membranes. These drugs are con-\nventionally used for neuropathic pain but also for nonspecific pain conditions [43, 44].\nTricyclic antidepressants are another first-line treatment for many neuropathic \nchronic pain conditions, by increasing available norepinephrine that inhibits \ndescending pain pathways [44]. An RCT in women with chronic pelvic pain compar-\ning the use of amitriptyline, gabapentin, and amitriptyline/gabapentin combined for \n24 months reported significantly reduced pain in each group and showed fewer side \neffects in the gabapentin group [45].\nAlmeida et  al. conducted a systematic review to evaluate the effect of neuromodu-\nlatory drugs on the intensity of chronic pelvic pain in women [46]. Among the seven \nstudies included, four showed improvement in pain with the use of neuromodulator \ndrugs for chronic pelvic pain. However, the most powerful and high-quality study \ndid not show pain improvement. Additionally , no studies specifically evaluating pain \nin women with endometriosis were found. There is still no high-quality evidence \nto either indicate or avoid the use of neuromodulatory drugs in endometriosis, and \nfurther high-quality studies, especially randomized controlled trials, are needed to \nsupport the use of these drugs in the treatment of women with endometriosis.\n3.2.3 Combined oral contraceptives\nThe utilization of combined oral contraceptives inhibits the production of \ngonadal estrogen by suppressing ovarian activity through a negative feedback axis. \nMedication Indication Dosing\nDepot MDA (Depo-Provera) Pain relief 150 mg intramuscularly every 3 months\nMDP A (Provera) Pain relief 30 to 100 mg daily (orally)\nCombined OCPs Pain relief 0.02 to 0.03 mg ethinyl estradiol and 0.15 mg desogestrel \ndaily for 6 months\nLevonorgestrel intrauterine \nsystem (Mirena)\nPain relief after \nsurgery\nIntrauterine system\nGonadotropin-releasing \nhormone analogues:\n• Goserelin (Zoladex)\n• Leuprolide (Lupron)\n• Triptorelin (Trelstar \nDepot)\nPain relief 3.75 mg of leuprolide injected every four weeks or 3.6 mg of \ngoserelin implanted subcutaneously for 6 months\nNafarelin (Synarel) Pain relief 200 mcg intranasally twice daily for 6 months\nDanazol (Danocrine) Pain relief 200 mg given orally three times daily; 400 mg given orally \ntwice daily for 6 months\nGestrinone Pain relief 2.5 mg orally twice a week for 6 months\nMDP A = medroxyprogesterone acetate; OCPs = oral contraceptive pills (Adapted from Gharaei et Gholampoor).\nTable 2. \nMedical treatment for endometriosis pain.\n\n63\nPain Management for Women with Endometriosis\nDOI: http://dx.doi.org/10.5772/intechopen.1007679\nConsequently , the release of estrogen-induced release of prostaglandins is reduced \nand inflammation decreases [47]. In addition, combined hormonal drugs are thought \nto cause decidualization followed by atrophy of endometrial tissue [48, 49]. When \nadministered for endometriosis, combined hormonal contraceptives should be used \ncontinuously in comparison to cyclic administration for symptom control [50].\n3.2.4 Progesterones\nNorethindrone acetate, depot medroxyprogesterone acetate (MP A), levonorg -\nestrel-releasing intrauterine system (LNG-IUS), and dienogest are some of the \nmost frequently used progestogens in women with endometriosis. Progestogens are \nproposed to work through several mechanisms [49]:\n1. decidualization and consequent endometrial atrophy .\n2. progestogen-induced suppression of matrix metalloproteinases, enzymes that \ninfluence the growth and ectopic implantation of endometrium.\n3. Inhibition of angiogenesis.\nTreatment with MP A, dydrogesterone, or norethindrone acetate has been shown to \nreduce pain scores by 70–100% [1]. MP A has proven to be an effective treatment with \ncombined oral contraceptives, danazol, and GnRH-agonists. Dienogest was reported as \nsignificantly better than placebo and as effective as GnRH-agonists with a more favorable \nside effect profile [51]. Levonorgestrel-releasing intrauterine systems have been proven \nmore effective in reducing dysmenorrhea after laparoscopic surgery when compared \nto expectant management and have been associated with a significant decrease in the \nextension of lesions encountered during second-look laparoscopy 6 months later [52].\n3.2.5 Gonadotropin-releasing hormone agonists\nGnRH agonist analogues have been studied more extensively than other medical \nlines of treatment [27 , 37]. Modified analogues present a longer half-life and bind to \nthe receptors in the pituitary gland, interrupting the pulsatile stimulation of endog -\nenous GnRH [53]. Consequently , downregulation of the pituitary-ovarian axis and \nhypoestrogenism induce amenorrhea and progressive atrophy of endometrial tissue \n[49]. Drug presentations include nafarelin acetate calibrated nasal spray , short-acting \nformulation for daily injection, and depot formulation every 1–3 months in the form of \nleuprolide acetate or goserelin acetate [29]. The main side effects reported are related \nto the induced hypoestrogenic state: hot flushes, vaginal dryness, decreased libido, \nmood swings, headache, and bone mineral depletion [54].\nA Cochrane review demonstrated GnRH-analogues to be more effective for pain \nthan placebo and similarly effective to LNG-IUS and danazol, with one long-term \nfollow-up demonstrating a 53% reduction in recurrence of symptoms at 24 months \nafter six-month treatment with GnRH-agonists [55]. Combined therapy with noreth-\nindrone acetate or an estrogen-progestogen regimen has been proposed as an alterna -\ntive to reduce estrogen deprivation effects and should be started at the same time of \nGnRH [27]. It has been proposed that the amount of estrogen/progesterone neces-\nsary to prevent hypoestrogenism symptoms is less than that which would stimulate \nendometriotic tissue formation [56].\n\nA Comprehensive Overview of Endometriosis\n64\n3.2.6 Gonadotropin-releasing hormone antagonists\nGnRH antagonists, such as Elagolix, suppress the gonadotropin hormone produc -\ntion from the pituitary gland and cause a dose-dependent hypoestrogenic state. In \ncontrast to GnRH agonists, they avoid the initial surge in LH and GSH and provide an \nimmediate effect [57]. Side effects may include symptoms of hypoestrogenism such \nas hot flashes, headaches, insomnia, and higher lipid levels. Elagolix has been recently \napproved in the USA for moderate to severe pain related to endometriosis, and its \nstudies have shown a significant short-term reduction of dysmenorrhea and non-\nmenstrual pelvic pain with adequate maintenance of response [58, 59].\n3.2.7 Danazol\nDanazol is a 17 alpha-ethinyltestosterone derivative that inhibits the LH peak and \nsteroidogenesis through the increase of free testosterone levels [49]. Its effectivity for \nthe treatment of endometriosis-related pain has proven to be superior to placebo and \ncomparable to GnRH-agonists [60]. Side effects include hirsutism, acne, weight gain, \nand deepening of voice. Danazol can be administered orally and through vaginal or \nintrauterine delivery systems [37].\n3.2.8 Experimental treatments: Gestrinone\nEthylnorgestrienone is an antiprogestational steroid that produces a progesterone \nwithdrawal effect at the endometrial cellular level and inhibits ovarian steroido-\ngenesis. It is administered orally from 2.5 to 10 mg daily to weekly basis, showing an \neffectiveness comparable to danazol and GnRH-agonists [55]. Side effects are associ-\nated with its androgenic and anti-estrogenic effects [49]. Gestrinone is not approved \nfor use in the USA, but its use is currently approved for Europe.\n3.2.9 Experimental treatments: Aromatase inhibitors\nAromatase inhibitors are still under current investigation, with low-impact \nstudies showing effectiveness in endometriosis-related pelvic pain treatment for \nwomen pre- and postmenopause [61]. Endometriotic tissue exhibits a higher level of \naromatase activity in comparison to eutopic endometrium. This results in an increase \nof local estrogen and favors endometriosis formation, explaining the persistence \nof endometriotic tissue in postmenopausal women and in those patients receiving \ntreatment with GnRH agonists [27]. In women who have not undergone menopause, \naromatase inhibitors should be used in combination with an additional agent that \ndown-regulates the ovaries and protects bone density such as progestogens, combined \noral contraceptives, or GnRH [62].\n3.3 Interventional pain management treatments\nEndometriosis-related pain could be treated effectively using interventional \npain management strategies. It has been stated that refractory pain due to endo-\nmetriosis should respond to nerve blocks depending on the site of involvement \n[63]. The sympathetic nervous system plays an essential role in the transmission of \npain from internal organs, independently of its cause [9]. The superior hypogastric \nplexus block (SHPB) is one commonly used approach in treating persistent pelvic \n\n65\nPain Management for Women with Endometriosis\nDOI: http://dx.doi.org/10.5772/intechopen.1007679\nand rectal pain that does not respond to conservative treatment [64, 65]. Located \nventrally to the abdominal aorta, the superior hypogastric plexus innervates hindgut \nstructures like the descendent and sigmoid colon, the proximal rectum, and pelvic \norgans such as the uterus and ovaries [66]. The SHPB procedure can be performed \nthrough either a paravertebral or transdiscal approach and has been reported to \nsignificantly improve the quality of life and mental health status of women with \nendometriosis [67]. The choice of analgesic injectate should be carefully done by \nthe physician considering the maximum analgesic effect while minimizing the side \neffects experienced by patients. Typical agents used include steroids, bupivacaine, \nand chemical agents such as (5–10%) and ethanol (50–100%) [68]. The inferior \nhypogastric plexus block (IHPB) is a less popular technique for the treatment of pel-\nvic, perineal, and genital pain due to its challenging location in the presacral space \nthat conditions a higher risk of nerve damage, vascular puncture, rectal lesion, \npresacral hematoma, and infection [69].\nThe ganglion impar block is another useful technique for the treatment of malig -\nnant vulvar, rectal, and anal pain; intractable sacral and perineal pain and coccydynia \n[70]. Other techniques for treating endometriosis-associated pain include performing \nS3 pulsed radiofrequency in combination with IHPB or botulinum toxin injection and \nmyofascial pain trigger points [71, 72].\nTargeting the sympathetic axes has been shown to be useful in controlling visceral \npelvic pain. The technique of choice should be based on clinical presentation and \nthe structures that are compromised [73]. SHPB is most effective for pain involving \npelvic viscera (e.g. uterus, ovaries, and bladder), the rectum, and hindgut structures \n[70]. When treating perineal, genital, presacral, and low pelvic pain, an IHPB is most \nrecommended [74, 75]. Ganglion impar block is an option in cases with involvement \nof the vulva and anal orifice, presence of intractable sacral and/or perineal pain, or \ncoccydynia. Gharaei and Gholampoor proposed an approach to the choice of inter-\nventional technique based on location and clinical presentation which is represented \nin Figure  1 [9].\n3.3.1 Hydrodissection with dextrose for peripheral nerve entrapment\nPeripheral nerve entrapment is an underrecognized entity when treating patients \nwith endometriosis and results in the persistence of pain and disability despite the \ntreatment offered. Entrapment of the nerve occurs due to anatomical or pathological \nstructures that cause increased pressure and lead to several mechanisms of nerve \ndamage, producing a segmental injury of the nerve. Symptoms can range from mild \ndiscomfort and numbness to debilitating pain and even paralysis. Injury of the nerve \nis produced by mechanical compression, contraction, and excessive stretching that \nleads to chronic hypoxia and inflammation. The resulting pain is of neuropathic \ncharacteristic which patients may describe as a numbing, tingling, burning, shooting, \nlancinating, or electric shock sensation [76]. Since central sensibilization can increase \npain over time, it is important to perform an early intervention. Hydrodissection \nconsists of a deep perineural injection into the compressing tissue or fascia, releasing \nthe trapped nerves while diluting and washing away the local inflammatory response \n[77]. Nerve structures are identified under ultrasound and a perineural injection \nwith 5% dextrose is administered. Dextrose reduces neuropathic inflammation and \ndissects the endometrial tissues. It has been proposed that dextrose delivered to the \nperineurial soft tissues may aid in nerve recovery by reducing adhesion and damage \nfrom chronic contraction and enhancing blood flow [78].\n\nA Comprehensive Overview of Endometriosis\n66\n3.4 Advanced neuromodulation techniques\nNeuromodulation consists of electrical stimulation or administration of pharma -\ncological agents that alter and moderate pain signals. Neuromodulation use has been \ndescribed for the treatment of chronic pelvic pain, including spinal cord stimulation \n(SCS), dorsal root ganglion (DRG) stimulation, sacral nerve roots stimulation, and \nperipheral nerve stimulation (PNS) [79].\n3.4.1 Spinal cord stimulator\nSCS has been proposed as a therapeutical option for refractory pelvic pain and \ncould be effective in endometriosis-related pain management [80]. Case series and \nprospective studies have been developed with variations in lead placement. Kapural \net  al. reported the first case series of SCS for refractory visceral pelvic pain in six \nwomen using an anterograde approach with lead placement at T11- T12. A significant \nreduction in the mean visual analog scale (V AS) score was reported, as well as a \nreduction in pain disability index and opioid use in morphine milligram equivalents \n(MME) [81]. Buffenior et  al. conducted a prospective study evaluating the role of SCS \nof the conus medullaris applied to 27 patients with refractory pudendal neuralgia. \nA total of 20 patients had a positive response during the trial period and underwent \npermanent electrode implantation, remaining long-term responders. At 15-month \nfollow-up, the mean estimated percent improvement (EPI) was 55.5% [82]. A case \nseries conducted by Simopoulous et  al. followed three patients who underwent \nimplantation of a high-frequency 10 KHz SCS mediated at the conus medullaris for \ndifferent clinical presentations of refractory neuropathic pelvic pain, reporting satis-\nfactory pain relief for all patients at long-term follow-up [83]. A prospective, multi-\ncenter trial performed by Tate et  al. evaluated the efficacy of 10-KHz SCS in patients \nwith chronic pelvic pain. Among the 21 patients who underwent the trial, 17 were \npositive respondents and 14 of them received a permanent SCS implantation. A total \nFigure 1. \nAlgorithmic approach to interventional pain management for neuropathic pain in endometriosis (Adapted from \nGharaei et al.).\n\n67\nPain Management for Women with Endometriosis\nDOI: http://dx.doi.org/10.5772/intechopen.1007679\nof 77% of the patients who underwent implantation reported pain relief over 50% \nand the mean V AS score decreased by 72% [84]. Hunter et  al. described lead place-\nment at higher thoracic levels for the management of chronic pelvic pain, with four \npatients who received SCS lead placement in the mid-thoracic region, two patients \nwith T6 level lead placement, and two patients who underwent T7 level trial. A total \nof three patients in the series had a positive trial response and received permanent \nimplantation [85]. A prospective chart review completed by De Andres et  al. found \nlimited effectiveness of retrograde neurostimulation in the treatment of perineal \npain, describing technical limitations and the complex pelvic innervation that does \nnot subscribe to a specific dermatome [86].\n3.4.2 Dorsal root ganglion stimulation\nSchu et  al. reviewed the use of DRG stimulation in patients with groin pain. A total \nof 29 patients were included and taken to trial with stimulation of the DRG between \nT12 and L4, resulting in 25 patients who were respondent and eligible for implanta -\ntion. Among the implanted patients, 82.6% experienced a reduction in pain superior \nto 50%. These results could indicate that neuromodulation of the DRG is effective in \ntreating pelvic neuropathic pain syndromes, including endometriosis [87]. Hunter \net  al. conducted the first case series of DRG stimulation in patients with chronic \npelvic pain that had not responded to conservative treatment and other interventional \npain management techniques. A total of seven patients were trialed successfully and \nunderwent DRG stimulator implants with lead placement over L1 and S2 DRGs bilat -\nerally . Pain relief report was satisfactory at follow-up, opioid consumption decreased, \nand some of the patients additionally reported improvement in urination and sexual \nfunction. The authors proposed that the lead placement generated an upstream and \ndownstream effect through crosstalk between the DRG and the ganglia, and sug -\ngested L1 as the most cephalad level in which inferior pain signals get transmitted \nto the brain. Stimulation of the L1 DRG stops the upper lumbar plexus signaling to \nthe brain and S2 DRG stimulation interrupts pain signals originating from the lower \nlumbar and sacral plexus [88].\n3.4.3 Peripheral nerve stimulation\nThe main targets for PNS described for chronic pelvic pain include the sacral, \npudendal, posterior tibial, genitofemoral, ilioinguinal, and iliohypogastric nerves \naccording to pain localization. PNS leads are aimed to be placed parallel to the periph-\neral nerve. Among sacral nerves, the most common target is the S3 root. Siegel et  al. \nand Paszkiewicz et  al. studied the effectiveness of sacral nerve stimulation in intrac -\ntable pelvic pain, performing a successful trial in 10 patients with lead placement in S3 \nor S4 foramen. At a median follow-up time of 19 months, the mean reduction of V AS \nwas superior to 50% [89]. Martelucci et  al. included 27 patients with chronic pelvic \npain in their study , of which 15 were trialed successfully and underwent implantation, \nfinding sustained pain relief at 60 months follow-up. Additionally , positive response to \ncalcium channel blockers such as pregabalin and gabapentin was found to be a predic -\ntor of positive response to sacral neuromodulation, while poorly localized pain was an \nindicator of poor response [90]. V ancaillie et  al. conducted one of the largest studies \ninvolving PNS consisting of a case series of 52 patients evaluating sacral neuromodula -\ntion for pelvic pain, with promising results indicating that sacral neuromodulation \ncould represent an effective treatment for intractable chronic pelvic pain [91].\n\nA Comprehensive Overview of Endometriosis\n68\nFurther high-quality research is needed to provide a strong recommendation for \nthe use of advanced neuromodulation techniques in endometriosis-related pain and \nstablish a consensus on neuromodulatory targets. Decisions on what technique is \nmost convenient should be based on pain location and a thorough medical evaluation. \nPossible risks and complications, patient’ s expectations, and the implications of a \nmedical device implantation should be discussed prior to the procedure.\n3.5 Adjuvant therapies\n3.5.1 Exercise\nPhysical exercise has been considered an adjuvant treatment for dysmenorrhea for \ndecades, considering that exercise releases anti-inflammatory cytokines and reduces \ncortisol levels, leading to a reduction in prostaglandin release [92]. Additionally , the \nskeletal muscle is believed to act as an endocrine organ, releasing myokines with \nmuscular contraction. These myokines are theorized to exert direct effects on the \nmuscle and other distal organs such as the liver, pancreas, and adipose tissue [93]. \nCarroquino-Garcia et  al. concluded in their systematic review that therapeutic exer-\ncise for a period of 8 to 12 weeks reduces pain intensity and duration of dysmenorrhea \n[94]. A recent systematic review by Mira et  al. reported an improvement in pain and \nquality of life when an exercise protocol was added to different pharmacological \ninterventions, however, due to the sample size of individual studies, the evidence \nwas not considered significant [95]. Given the low risk of the intervention and the \npotential benefits to the patients’ overall health, exercise in conjunction with other \ntreatment modalities could be encouraged to alleviate symptoms [96].\n3.5.2 Acupuncture\nStudies regarding the use of acupuncture in endometriosis-related pain are \nincreasing worldwide. Two randomized trials evaluated specific acupuncture com-\npared to sham acupuncture for endometriosis-related pain finding significantly better \npain control with real acupuncture [97 , 98]. Xu et  al. demonstrated in their systematic \nreview that acupuncture had a beneficial effect on pain reduction compared to \nother treatments such as traditional Chinese medicine, medication, or placebo [99]. \nAcupuncture has been suggested to activate peripheral analgesic mechanisms such \nas the release of endogenous opioids and to participate in the modulation of several \nanti-inflammatory pathways, and inhibitory control mechanisms [100]. These find-\nings were corroborated by a recent meta-analysis involving the use of acupuncture \ncompared to placebo for women with endometriosis-related pelvic pain [95].\n3.5.3 Behavioral health\nChronic pelvic pain has been associated with a higher prevalence of psychologic \nsymptoms such as depression and anxiety , and a significant reduction in work productiv -\nity [101]. Most women with endometriosis and pelvic pain present some level of impair -\nment in their mental health and quality of life associated to the chronicity and emotional \naspects of the disease [102]. Furthermore, around 67% of women with endometriosis \nexperience problems in the relationship with their partners, mainly due to painful inter -\ncourse [103, 104]. This complex interplay of factors, also referred to as the biopsychoso -\ncial injuries caused by the disease, could induce a vicious cycle that compromises the base \n\n69\nPain Management for Women with Endometriosis\nDOI: http://dx.doi.org/10.5772/intechopen.1007679\ntreatment, whether it is pharmacological or surgical [105]. Buggio et  al. described a series \nof interventions for women with endometriosis, including psychotherapy and sexual \ntherapy , that approach the self-management of physical, psychological, and sexual \nsymptoms obtaining positive outcomes when integrated into the clinical treatment of \npain [106]. Practitioners should consider referral to a mental health professional early in \nthe treatment to address the psychological and social factors that contribute to pain.\n3.5.4 Pelvic floor physical therapy\nChronic pelvic pain leads to muscle contraction and postural changes that exac -\nerbate musculoskeletal pain. Physical therapy , including heat therapy , has been \nproposed to enhance the relaxation of abdominal muscles and increase pelvic blood \ncirculation [92]. There is no strong evidence with a well-described methodology for \nrecommending the different forms of physiotherapy that may be most effective in the \ntreatment of endometriosis. Current reviews indicate that transcutaneous electrical \nnerve stimulation (TENS), pulsed high-intensity laser therapy , pulsed electromag -\nnetic fields, and manual physiotherapy could be of use in reducing pain and improv -\ning the quality of life for women with endometriosis [107].\n4. Conclusions\n• Endometriosis is a challenging, undertreated chronic condition that severely \nimpacts the quality of life of women and adolescents globally .\n• Understanding the pathogenesis of the disease and pain mechanism is crucial to \noffer an integrated and effective treatment strategy .\n• A significant proportion of patients respond well to medical therapy; however, \nhormonal treatment can lead to several secondary effects, and in a great number \nof patients, symptoms recur once the medication is terminated.\n• Interventional pain management strategies have been shown to be effective with \nfewer adverse effects but require a clear understanding of pelvic anatomy and \ninnervation and a thorough medical evaluation to identify nerve involvement \nand/or entrapment. The sympathetic nervous system is the focus of analgesic \ninjections for endometriosis-related pelvic pain. Risks and possible complica -\ntions such as nerve damage, vascular puncture, visceral lesion, and hematoma \nshould be discussed with the patient prior to the procedure.\n• Further investigation is required to stablish stronger recommendations and \nguidelines regarding interventional analgesic procedures.\n• Advanced neuromodulatory techniques are promising in the scenario of refrac -\ntory pelvic pain considering the importance of neuropathic component in \nendometriosis-related pain. A neuromodulatory target should be accurately \ndetermined for the procedure according to the localization of pain.\n• Adjuvant therapies are encouraged through the process of diagnosis and \ntreatment to optimize pain control and quality of life. Acupuncture has been \n\nA Comprehensive Overview of Endometriosis\n70\nAuthor details\nDaniela Rangel-Santos 1,2,3 *, German William Rangel 1,2  and Sudhir Diwan 3\n1 Department of Anesthesiology and Pain Medicine, Universidad Autónoma de \nBucaramanga UNAB, Bucaramanga, Colombia\n2 Pain and Palliative Care Clinic ALIVIAR SAS, Floridablanca, Colombia\n3 Advanced Spine on Park Avenue, New Y ork, NY , USA\n* Address all correspondence to: rangelsdaniela@gmail.com\ndemonstrated to improve pain when compared to placebo, however, no strong \nrecommendation can be provided regarding its use in patients with endometrio-\nsis. Other interventions could be incorporated according to the patient’ s toler-\nance and best medical judgment.\nAcknowledgements\nW e would like to give our warmest thanks to the team at Advanced Spine on \nPark Avenue in New  Y ork City and ALIVIAR Pain and Palliative Care Clinic in \nBucaramanga, Colombia, who every day make our work possible and pleasant.\nConflict of interest\nDr. Daniela Rangel-Santos, Dr. German William Rangel, and Dr. Sudhir Diwan \ndeclare no conflict of interest.\n© 2024 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of \nthe Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), \nwhich permits unrestricted use, distribution, and reproduction in any medium, provided \nthe original work is properly cited. \n\nPain Management for Women with Endometriosis\nDOI: http://dx.doi.org/10.5772/intechopen.1007679\n71\nReferences\n[1] Carlyle D, Khader T , Lam D, \nV adivelu N, Shiwlochan D, Y onghee C. \nEndometriosis pain management: A \nreview . In: Current Pain and Headache \nReports. V ol. 24. Berlin, Germany: \nSpringer Science+Business Media; 2020\n[2] W ee-Stekly WW , Kew CCY , \nChern BSM. Endometriosis: A review \nof the diagnosis and pain management. \nIn: Gynecology and Minimally Invasive \nTherapy . V ol. 4. Taiwan: Elsevier; \n2015.  pp.  106-109\n[3] Mounsey AL, Slawson DC. Diagnosis \nand Management of Endometriosis \n[Internet]. 2006. Available from: www .\naafp.org/afp.\n[4] Burney RO, Giudice LC.  \nPathogenesis and pathophysiology of \nendometriosis. Fertility and Sterility . \n2012; 98(3):511-519\n[5] International working group of AAGL \nEE and W , Tomassetti C, Johnson NP , \nPetrozza J, Abrao MS, Einarsson JI, \net  al. An international terminology \nfor endometriosis, 2021. Journal of \nMinimally Invasive Gynecology . \n2021;28 (11):1849-1859\n[6] Kitawaki J, Kado N, Ishihara H, \nKoshiba H, Kitaoka Y , Honjo H. \nEndometriosis: The pathophysiology \nas an estrogen-dependent disease. The \nJournal of Steroid Biochemistry and \nMolecular Biology . 2002;83 (1-5):149-155\n[7] Mechsner S. Endometriosis, an \nongoing pain—step-by-step treatment. \nJournal of Clinical Medicine. MDPI. \n2022, 2022;11:467\n[8] Chiantera V , Abesadze E, Mechsner S. \nHow to understand the complexity of \nendometriosis-related pain. Journal of \nEndometriosis and Pelvic Pain Disorders. \n2017; 9(1):30-38\n[9] Gholampoor N, Gharaei H, \nStudent M. The Role of Interventional \nPain Management Strategies for \nNeuropathic Pelvic Pain in Endometriosis \n[Internet]. Available from: www .\npainphysicianjournal.com\n[10] Dunselman GAJ, V ermeulen N, \nBecker C, Calhaz-Jorge C, D’Hooghe T , \nDe Bie B, et  al. ESHRE guideline: \nManagement of women with \nendometriosis. Human Reproduction. \n2014; 29(3):400-412\n[11] Thiel P , Kobylianskii A, \nMcGrattan M, Lemos N. Entrapped by \npain: The diagnosis and management \nof endometriosis affecting somatic \nnerves. In: Best Practice and Research: \nClinical Obstetrics and Gynaecology . \nAmsterdam, The Netherlands: Elsevier; \n2024\n[12] Nicholas M, Vlaeyen JWS, Rief W , \nBarke A, Aziz Q, Benoliel R, et  al. The \nIASP classification of chronic pain for \nICD-11: Chronic primary pain. Pain. \n2019;160 (1):28-37\n[13] Oh SB, Tran PB, Gillard SE, \nHurley RW , Hammond DL, Miller RJ. \nChemokines and glycoprotein120 \nproduce pain hypersensitivity by \ndirectly exciting primary nociceptive \nneurons. The Journal of Neuroscience. \n2001; 21(14):5027-5035\n[14] Bedaiwy MA, Falcone T , \nGoldberg JM, Sharma RK, Nelson DR, \nAgarwal A. Peritoneal fluid leptin is \nassociated with chronic pelvic pain \nbut not infertility in endometriosis \npatients*. Human Reproduction. \n2006; 21(3):788-791\n\nA Comprehensive Overview of Endometriosis\n72\n[15] Bedaiwy MA. Prediction of \nendometriosis with serum and \nperitoneal fluid markers: A prospective \ncontrolled trial. Human Reproduction. \n2002; 17(2):426-431\n[16] Buyalos RP , Funari V A,  \nAzziz R, Watson JM, Martinez-\nMaza O. Elevated interleukin-6 levels \nin peritoneal fluid of patients with \npelvic pathology . Fertility and Sterility . \n1992;58 (2):302-306\n[17] Nirgianakis K, Bersinger NA, \nMcKinnon B, Kostov P , Imboden S, \nMueller MD. Regression of the \ninflammatory microenvironment of \nthe peritoneal cavity in women with \nendometriosis by GnRHa treatment. \nEuropean Journal of Obstetrics & \nGynecology and Reproductive Biology . \n2013;170 (2):550-554\n[18] Anaf V , Simon P , El Nakadi I, \nFayt I, Simonart T , Buxant F , et  al. \nHyperalgesia, nerve infiltration and \nnerve growth factor expression in \ndeep adenomyotic nodules, peritoneal \nand ovarian endometriosis. Human \nReproduction. 2002;17 (7):1895-1900\n[19] McKinnon BD, Bertschi D, \nBersinger NA, Mueller MD. \nInflammation and nerve fiber \ninteraction in endometriotic pain. \nTrends in Endocrinology & Metabolism. \n2015; 26(1):1-10\n[20] As-Sanie S, Harris RE, Napadow V , \nKim J, Neshewat G, Kairys A, et  al. \nChanges in regional gray matter volume \nin women with chronic pelvic pain: A \nvoxel-based morphometry study . Pain. \n2012; 153(5):1006-1014\n[21] Anaf V . Relationship between \nendometriotic foci and nerves \nin rectovaginal endometriotic \nnodules. Human Reproduction. \n2000; 15(8):1744-1750\n[22] Biswas B, Gupta N, Magon N. \nIncisional endometriosis: A rare cause for \na painful scar - a report and commentary . \nNigerian Medical Journal. 2012;53 (4):257\n[23] Baskan O, Ozdemir F . Endometriosis \nof the sciatic nerve with cyclic sciatica. \nActa Medica Lituanica. 2014;21:99-102\n[24] Steinberg JA, Gonda DD, Muller K, \nCiacci JD. Endometriosis of the conus \nmedullaris causing cyclic radiculopathy . \nJournal of Neurosurgery . Spine. \n2014; 21(5):799-804\n[25] Krames ES. The dorsal root \nganglion in chronic pain and as a \ntarget for neuromodulation: A review . \nNeuromodulation: Technology at the \nNeural Interface. 2015;18 (1):24-32\n[26] Origoni M, Leone Roberti Maggiore U, \nSalvatore S, Candiani M. Neurobiological \nmechanisms of pelvic pain. BioMed \nResearch International. 2014;2014 :1-9\n[27] Practice Committee of the American \nSociety for Reproductive Medicine. \nTreatment of pelvic pain associated \nwith endometriosis: A committee \nopinion. Fertility and Sterility . \n2014; 101(4):927-935\n[28] Chaichian S, Kabir A, \nMehdizadehkashi A, Rahmani K, \nMoghimi M, Moazzami B. Comparing the \nefficacy of surgery and medical therapy \nfor pain management in endometriosis: \nA systematic review and meta-analysis. \nPain Physician. 2017;20 (3):185-195\n[29] Mettler L, Ruprai R, Alkatout I. \nImpact of medical and surgical \ntreatment of endometriosis on the cure \nof endometriosis and pain. BioMed \nResearch International. 2014;2014 :1-9\n[30] Berlanda N, V ercellini P , Fedele L. \nThe outcomes of repeat surgery for \nrecurrent symptomatic endometriosis. \n\nPain Management for Women with Endometriosis\nDOI: http://dx.doi.org/10.5772/intechopen.1007679\n73\nCurrent Opinion in Obstetrics & \nGynecology . 2010;22 (4):320-325\n[31] Shakiba K, Bena JF , McGill KM, \nMinger J, Falcone T . Surgical treatment \nof endometriosis. Obstetrics & \nGynecology . 2008;111(6):1285-1292\n[32] Marana R, Caruana P , Muzii L, \nCatalano GF , Mancuso S. Operative \nlaparoscopy for ovarian cysts. \nExcision vs. aspiration. The \nJournal of Reproductive Medicine. \n1996;41 (6):435-438\n[33] Proctor M, Latthe P , Farquhar C, \nKhan K, Johnson N. Surgical interruption \nof pelvic nerve pathways for primary and \nsecondary dysmenorrhoea. Cochrane \nDatabase of Systematic Reviews. \n2005; 2010(11):CD001896\n[34] V ercellini P , Aimi G, Busacca M, \nApolone G, Uglietti A, Crosignani PG. \nLaparoscopic uterosacral ligament \nresection for dysmenorrhea associated \nwith endometriosis: Results of a \nrandomized, controlled trial. Fertility \nand Sterility . 2003;80(2):310-319\n[35] Zullo F , Palomba S, Zupi E, \nRusso T , Morelli M, Cappiello F , et  al. \nEffectiveness of presacral neurectomy in \nwomen with severe dysmenorrhea caused \nby endometriosis who were treated \nwith laparoscopic conservative surgery: \nA 1-year prospective randomized \ndouble-blind controlled trial. American \nJournal of Obstetrics and Gynecology . \n2003; 189(1):5-10\n[36] Shakiba K, Bena JF , McGill KM, \nMinger J, Falcone T . Surgical treatment \nof endometriosis: A 7-year follow-up \non the requirement for further \nsurgery . Obstetrics and Gynecology . \n2008; 111(6):1285-1292\n[37] Gambone JC, Mittman BS, \nMunro MG, Scialli AR, Winkel CA. \nConsensus statement for the \nmanagement of chronic pelvic pain and \nendometriosis: Proceedings of an expert-\npanel consensus process. Fertility and \nSterility . 2002;78(5):961-972\n[38] Marjoribanks J, Ayeleke RO, \nFarquhar C, Proctor M. Nonsteroidal \nanti-inflammatory drugs for \ndysmenorrhoea. Cochrane Database of \nSystematic Reviews. 2015;2015 (7):20-28\n[39] Allen C, Hopewell S, Prentice A, \nGregory D. Non-steroidal anti-\ninflammatory drugs for pain in women \nwith endometriosis. In: Allen C, editor. \nCochrane Database of Systematic \nReviews. Chichester, UK: John Wiley & \nSons, Ltd; 2005\n[40] Kauppila A, Puolakka J, Ylikorkala O. \nProstaglandin biosynthesis inhibitors \nand endometriosis. Prostaglandins. \n1979;18 (4):655-661\n[41] Kauppila A, Rönnberg L. Naproxen \nsodium in dysmenorrhea secondary \nto endometriosis. Obstetrics and \nGynecology . 1985;65 (3):379-383\n[42] Brown J, Crawford TJ, Allen C, \nHopewell S, Prentice A. Nonsteroidal \nanti-inflammatory drugs for pain in \nwomen with endometriosis. Cochrane \nDatabase of Systematic Reviews. \n2017; 1(1):CD004753\n[43] Gritsenko K, Cohen MS.  \nPelvic pain. In: Essentials of Pain \nMedicine [Internet]. Amsterdam, The \nNetherlands: Elsevier; 2018. pp.  261-\n272.e4. Available from: https://\nlinkinghub.elsevier.com/retrieve/pii/\nB9780323401968000310\n[44] Kremer M, Salvat E, Muller A, \nY alcin I, Barrot M. Antidepressants and \ngabapentinoids in neuropathic pain: \nMechanistic insights. Neuroscience. \n2016; 338:183-206\n\nA Comprehensive Overview of Endometriosis\n74\n[45] Sator-Katzenschlager SM, \nScharbert G, Kress HG, Frickey N, \nEllend A, Gleiss A, et  al. Chronic \npelvic pain treated with gabapentin \nand amitriptyline: A randomized \ncontrolled pilot study . Wiener Klinische \nW ochenschrift. 2005;117 (21-22):761-768\n[46] Andrade MA, Soares LC, MAP DO. \nThe effect of neuromodulatory drugs \non the intensity of chronic pelvic pain \nin women: A systematic review . Revista \nBrasileira de Ginecologia e Obstetrícia. \n2022; 44 (9):891-898\n[47] V ercellini P , Trespidi L, Colombo A, \nV endola N, Marchini M, Crosignani PG. \nA gonadotropin-releasing hormone \nagonist versus a low-dose oral \ncontraceptive for pelvic pain associated \nwith endometriosis. Fertility and \nSterility . 1993;60 (1):75-79\n[48] Zito G, Luppi S, Giolo E, \nMartinelli M, V enturin I, Di \nLorenzo G, et  al. Medical treatments \nfor endometriosis-associated pelvic \npain. BioMed Research International. \n2014; 2014:1-12\n[49] Olive D, L. Medical therapy of \nendometriosis. Seminars in Reproductive \nMedicine. 2003;21(2):209-222\n[50] Harada T , Momoeda M, Taketani Y , \nHoshiai H, Terakawa N. Low-dose oral \ncontraceptive pill for dysmenorrhea \nassociated with endometriosis: A \nplacebo-controlled, double-blind, \nrandomized trial. Fertility and Sterility . \n2008; 90(5):1583-1588\n[51] McCormack PL. Dienogest. Drugs. \n2010; 70(16):2073-2088\n[52] Lockhat FB. The evaluation of \nthe effectiveness of an intrauterine-\nadministered progestogen \n(levonorgestrel) in the symptomatic \ntreatment of endometriosis and in \nthe staging of the disease. Human \nReproduction. 2004;19 (1):179-184\n[53] V eth VB, van de Kar MM, \nMcDonnell R, Julania S, Hart RJ. \nGonadotrophin-releasing hormone \nanalogues for pain associated \nwith endometriosis. Cochrane \nDatabase of Systematic Reviews. \n2010; 2023(11):CD008475\n[54] Farmer JE, Prentice A, Breeze A, \nAhmad G, Duffy JM, Watson A, et  al. \nGonadotrophin-releasing hormone \nanalogues for endometriosis: Bone \nmineral density . Cochrane Database of \nSystematic Reviews. 2003;2003 :CD001297\n[55] Brown J, Pan A, Hart RJ. \nGonadotrophin-releasing hormone \nanalogues for pain associated \nwith endometriosis. Cochrane \nDatabase of Systematic Reviews. \n2010; 2010(12):CD008475\n[56] Barbieri RL. Endometriosis and the \nestrogen threshold theory . Relation to \nsurgical and medical treatment. The \nJournal of Reproductive Medicine. \n1998;43 (3 Suppl):287-292\n[57] Bedaiwy MA, Alfaraj S, Y ong P , \nCasper R. New developments \nin the medical treatment of \nendometriosis. Fertility and Sterility . \n2017; 107(3):555-565\n[58] Taylor HS, Giudice LC, Lessey BA, \nAbrao MS, Kotarski J, Archer DF , et  al. \nTreatment of endometriosis-associated \npain with Elagolix, an oral GnRH \nantagonist. The New England Journal of \nMedicine. 2017;377(1):28-40\n[59] Surrey E, Taylor HS, Giudice L, \nLessey BA, Abrao MS, Archer DF , et  al. \nLong-term outcomes of Elagolix in \nwomen with endometriosis: Results from \ntwo extension studies. Obstetrics and \nGynecology . 2018;132 (1):147-160\n\nPain Management for Women with Endometriosis\nDOI: http://dx.doi.org/10.5772/intechopen.1007679\n75\n[60] Farquhar C, Prentice A, Singla AA, \nSelak V . Danazol for pelvic pain associated \nwith endometriosis. Cochrane Database \nof Systematic Reviews. 2007;4 :2-6\n[61] Patwardhan S, Nawathe A, Y ates D, \nHarrison G, Khan K. Systematic \nreview of the effects of aromatase \ninhibitors on pain associated with \nendometriosis. BJOG: An International \nJournal of Obstetrics and Gynaecology . \n2008; 115(7):818-822\n[62] Pavone ME, Bulun SE. Aromatase \ninhibitors for the treatment of \nendometriosis. Fertility and Sterility . \n2012; 98(6):1370-1379\n[63] Malec-Milewska M, Horosz B, \nSękowska A, Kolęda I, Kosson D, \nJakiel G. Pharmacological treatment and \nregional anesthesia techniques for pain \nmanagement after completion of both \nconservative and surgical treatment of \nendometriosis and pelvic adhesions in \nwomen with chronic pelvic pain as a \nmandated treatment strategy . Annals \nof Agricultural and Environmental \nMedicine. 2015;22 (2):353-356\n[64] Khodaverdi S, Alebouyeh MR, \nSadegi K, Mehdizadehkashi A, \nKaveh M, Entezari SR, et  al. Superior \nhypogastric plexus block as an effective \ntreatment method for endometriosis-\nrelated chronic pelvic pain: An open-\nlabel pilot clinical trial. Journal of \nObstetrics and Gynaecology (Lahore). \n2021;41 (6):966-971\n[65] Gulati A, Bhatnagar S, Rakesh N, \nY ousefi A, Hernandez-Porras C. Superior \nhypogastric plexus and ganglion impar \nblock. In: Regional Nerve Blocks in \nAnesthesia and Pain Therapy . Cham: \nSpringer International Publishing; \n2022.  pp.  667-672\n[66] Tharian AR, Kusper TM, \nKnezevic NN. Superior hypogastric \nplexus. In: Pain. Cham: Springer \nInternational Publishing; \n2019.  pp.  851-854\n[67] Y ang X, Y ou J, Tao S, Zheng X, \nXie K, Huang B. Computed tomography-\nguided superior hypogastric plexus \nblock for secondary dysmenorrhea in \nperimenopausal women. Medical Science \nMonitor. 2018;24 :5132-5138\n[68] Urits I, Schwartz R, Herman J, \nBerger AA, Lee D, Lee C, et  al. A \ncomprehensive update of the superior \nhypogastric block for the management \nof chronic pelvic pain. Current Pain and \nHeadache Reports. 2021;25 (3):13\n[69] Schultz DM. Inferior hypogastric \nplexus blockade: A transsacral approach. \nPain Physician. 2007;10 (6):757-763\n[70] Plancarte-Sánchez R, Guajardo-\nRosas J, Guillen-Nuñez R. Superior \nhypogastric plexus block and ganglion \nimpar (Walther). Techniques in Regional \nAnesthesia and Pain Management. \n2005; 9(2 SPEC. ISS):86-90\n[71] Gunduz OH, Kenis CO. Ganglion \nblocks as a treatment of pain: Current \nperspectives. Journal of Pain Research. \n2017; 10:2815-2826\n[72] Nagpal AS, Moody EL. Interventional \nmanagement for pelvic pain. Physical \nMedicine and Rehabilitation Clinics of \nNorth America. 2017;28 (3):621-646\n[73] V orenkamp K, Yi P , Kemp A. \nSympathetic blocks for visceral pain. \nPhysical Medicine and Rehabilitation \nClinics of North America. \n2022; 33(2):475-487\n[74] Choi HS, Kim YH, Han JW , \nMoon DE. A new technique for inferior \nhypogastric plexus block: A coccygeal \ntransverse approach: A case report. \nKorean Journal of Pain. 2012;25 (1):38-42\n\nA Comprehensive Overview of Endometriosis\n76\n[75] Stogicza A. Superior and inferior \nhypogastric plexus blocks. In: Diwan S, \nStaats PS, editors. Atlas of Pain Medicine \nProcedures [Internet]. New  Y ork, NY: \nMcGraw-Hill Education; 2015. Available \nfrom: accessanesthesiology .mhmedical.\ncom/content.aspx?aid=1107198439\n[76] Trescot A, Brown M. Peripheral \nnerve entrapment, hydrodissection,  \nand neural regenerative strategies. Tech \nReg Anesth Pain Manag. 2015;19 (1-2): \n85-93\n[77] Gharaei H, Diwan S. COVID-19 \npandemic: Implications on interventional \npain practice-a narrative review . Pain \nPhysician. 2020;23(4S):S311-S318\n[78] Wu YT , Wu CH, Lin JA, Su D, \nHung CY , Lam SKH. Efficacy of 5% \ndextrose water injection for peripheral \nentrapment neuropathy: A narrative \nreview . International Journal of \nMolecular Sciences. 2021;22 (22):12358\n[79] Roy H, Offiah I, Dua A. \nNeuromodulation for pelvic and \nurogenital pain. Brain Sciences. \n2018; 8(10):180\n[80] Diwan S, Patel CB, Patel AA.  \nThe Role of Neuromodulation in  \nChronic Pelvic Pain: A Review \nArticle. Available from: www .\npainphysicianjournal.com\n[81] Kapural L, Narouze SN, Janicki TI, \nMekhail N. Spinal cord stimulation is \nan effective treatment for the chronic \nintractable visceral pelvic pain. Pain \nMedicine. 2006;7(5):440-443\n[82] Buffenoir K, Rioult B, Hamel O, \nLabat JJ, Riant T , Robert R. Spinal cord \nstimulation of the conus medullaris \nfor refractory pudendal neuralgia: A \nprospective study of 27 consecutive \ncases. Neurourology and Urodynamics. \n2015; 34(2):177-182\n[83] Simopoulos T , Y ong RJ, Gill JS. \nTreatment of chronic refractory \nneuropathic pelvic pain with high-\nfrequency 10-kilohertz spinal \ncord stimulation. Pain Practice. \n2018; 18(6):805-809\n[84] Tate JL, Stauss T , Li S, Rotte A, \nSubbaroyan J. A prospective, multi-\ncenter, clinical trial of a 10-kHz spinal \ncord stimulation system in the treatment \nof chronic pelvic pain. Pain Practice. \n2021;21(1):45-53\n[85] Hunter C, Davé N, Diwan S, Deer T . \nNeuromodulation of pelvic visceral pain: \nReview of the literature and case series \nof potential novel targets for treatment. \nPain Practice. 2013;13 (1):3-17\n[86] De Andres J, Perotti L, Villaneuva-\nPerez VL, Asensio-Samper JM, Fabregat-\nCid G. Role of lumbosacral retrograde \nneuromodulation in the treatment \nof painful disorders. Pain Physician. \n2013;16 (2):145-153\n[87] Schu S, Gulve A, ElDabe S, \nBaranidharan G, W olf K, Demmel W , \net  al. Spinal cord stimulation of the \ndorsal root ganglion for groin pain—A \nretrospective review . Pain Practice. \n2015; 15(4):293-299\n[88] Hunter CW , Y ang A. Dorsal root \nganglion stimulation for chronic \npelvic pain: A case series and technical \nreport on a novel Lead configuration. \nNeuromodulation: Technology at the \nNeural Interface. 2019;22 (1):87-95\n[89] Paszkiewicz EJ, Siegel SW , \nKirkpatrick C, Hinkel B, Keeisha J, \nKirkemo A. Sacral nerve stimulation in \npatients with chronic, intractable pelvic \npain. Urology . 2001;57 (6):124\n[90] Martellucci J, Naldini G, Carriero A. \nSacral nerve modulation in the treatment \nof chronic pelvic pain. International \n\nPain Management for Women with Endometriosis\nDOI: http://dx.doi.org/10.5772/intechopen.1007679\n77\nJournal of Colorectal Disease. \n2012; 27(7):921-926\n[91] V ancaillie T , Kite L, Howard E, \nChow J. Sacral neuromodulation for \npelvic pain and pelvic organ dysfunction: \nA case series. Australian and New \nZealand Journal of Obstetrics and \nGynaecology . 2018;58 (1):102-107\n[92] Kirsch E, Rahman S, Kerolus K, \nHasan R, Kowalska DB, Desai A, et  al. \nDysmenorrhea, a narrative review of \ntherapeutic options. Journal of Pain \nResearch. 2024;17 :2657-2666\n[93] Tourny C, Zouita A, El Kababi S, \nFeuillet L, Saeidi A, Laher I, et  al. \nEndometriosis and physical activity: \nA narrative review . International \nJournal of Gynaecology and Obstetrics. \n2023; 163(3):747-756\n[94] Carroquino-Garcia P , Jiménez-\nRejano JJ, Medrano-Sanchez E, de la \nCasa-Almeida M, Diaz-Mohedo E, \nSuarez-Serrano C. Therapeutic \nexercise in the treatment of primary \ndysmenorrhea: A systematic review \nand meta-analysis. Physical Therapy . \n2019;99(10):1371-1380\n[95] Mira T AA, Buen MM, Borges MG, \nY ela DA, Benetti-Pinto CL. Systematic \nreview and meta-analysis of \ncomplementary treatments for women \nwith symptomatic endometriosis. \nInternational Journal of Gynaecology \nand Obstetrics. 2018;143 (1):2-9\n[96] Armour M, Ee CC, Naidoo D, \nAyati Z, Chalmers KJ, Steel KA, et  al. \nExercise for dysmenorrhoea. Cochrane \nDatabase of Systematic Reviews. \n2019;9(9):CD004142\n[97] Wayne PM, Kerr CE, Schnyer RN, \nLegedza ATR, Savetsky-German J, \nShields MH, et  al. Japanese-style \nacupuncture for endometriosis-related \npelvic pain in adolescents and young \nwomen: Results of a randomized \nsham-controlled trial. Journal of \nPediatric and Adolescent Gynecology . \n2008; 21(5):247-257\n[98] Rubi-Klein K, Kucera-Sliutz E, \nNissel H, Bijak M, Stockenhuber D, \nFink M, et  al. Is acupuncture in addition \nto conventional medicine effective \nas pain treatment for endometriosis? \nEuropean Journal of Obstetrics & \nGynecology and Reproductive Biology . \n2010; 153(1):90-93\n[99] Xu Y , Zhao W , Li T , Zhao Y , Bu H, \nSong S. Effects of acupuncture for the \ntreatment of endometriosis-related pain: \nA systematic review and meta-analysis. \nPLoS One. 2017;12 (10):e0186616\n[100] Leung L. Neurophysiological  \nbasis of acupuncture-induced \nanalgesia--an updated review . Journal \nof Acupuncture and Meridian Studies. \n2012; 5(6):261-270\n[101] Moradi M, Parker M, Sneddon A, \nLopez V , Ellwood D. Impact of \nendometriosis on women’ s lives: A \nqualitative study . BMC W omen's Health. \n2014; 14:123\n[102] Facchin F , Barbara G, Saita E, \nMosconi P , Roberto A, Fedele L, et  al. \nImpact of endometriosis on quality of \nlife and mental health: Pelvic pain makes \nthe difference. Journal of Psychosomatic \nObstetrics and Gynaecology . \n2015; 36(4):135-141\n[103] De Graaff AA, Van Lankveld J, \nSmits LJ, V an Beek JJ, Dunselman GAJ. \nDyspareunia and depressive symptoms \nare associated with impaired \nsexual functioning in women with \nendometriosis, whereas sexual \nfunctioning in their male partners is \nnot affected. Human Reproduction. \n2016; 31(11):2577-2586\n\nA Comprehensive Overview of Endometriosis\n78\n[104] Pluchino N, W enger JM, Petignat P , \nTal R, Bolmont M, Taylor HS, et  al. \nSexual function in endometriosis \npatients and their partners: Effect \nof the disease and consequences of \ntreatment. Human Reproduction Update. \n2016; 22(6):762-774\n[105] Márki G, Bokor A, Rigó J, Rigó A. \nPhysical pain and emotion regulation \nas the main predictive factors of \nhealth-related quality of life in women \nliving with endometriosis. Human \nReproduction. 2017;32 (7):1432-1438\n[106] Buggio L, Barbara G, Facchin F , \nFrattaruolo MP , Aimi G, Berlanda N. \nSelf-management and psychological-\nsexological interventions in patients with \nendometriosis: Strategies, outcomes, \nand integration into clinical care. \nInternational Journal of W omen's Health. \n2017; 9:281-293\n[107] W ójcik M, Szczepaniak R, \nPlacek K. Physiotherapy management \nin endometriosis. International Journal \nof Environmental Research and Public \nHealth. MDPI. 2022;19 :16148\n\n79\nChapter 5\nAdvances in Endometriosis \nResearch: From Pathogenesis to \nPrevention\nAshish Ashish, Shivani Mishra, Sangeeta Rai, Kusum Kusum, \nGunjan Rai and Royana Singh\nAbstract\nThis chapter provides a comprehensive analysis of the genetic factors and envi-\nronmental influences contributing to endometriosis, highlighting recent advances in \ngenomic research and their implications for personalized medicine approaches. It delves \ninto the genetic underpinnings of endometriosis, exploring the latest research findings \non genetic factors that contribute to susceptibility , disease progression, and potential \ntherapeutic targets. The chapter provides insight through a review of Genome- Wide \nAssociation Studies (GW AS) and candidate gene studies, highlighting the key genetic \nvariants associated with endometriosis. Additionally , it discusses the complex interplay \nbetween genetic predisposition and environmental factors in the development of endo-\nmetriosis. Furthermore, it explores emerging technologies and methodologies, such as \nnext-generation sequencing (NGS) and functional genomics, for unraveling the genetic \ncomplexity of endometriosis. Finally , the chapter discusses the implications of genetic \nresearch for personalized diagnosis, treatment, and prevention strategies in endome-\ntriosis management. These findings have the potential to significantly impact clinical \npractice and patient outcomes, paving the way for earlier diagnosis, targeted therapies, \nand improved quality of life for individuals affected by endometriosis.\nKeywords: infertility , genetics, biomarkers, diagnosis, epigenetics, endometriosis, \nepidemiology\n1.Introduction\nEndometriosis is a chronic condition where tissue resembling the endometrium \ngrows outside the uterus, triggering ongoing inflammation [1]. It impacts approxi-\nmately 10% of reproductive-age women globally , leading to symptoms like infertility , \npainful menstruation, and pelvic discomfort. Despite its prevalence, the precise \nmechanisms behind endometriosis remain poorly understood [2]. Recent progress in \ngenetic research has highlighted the genetic factors influencing susceptibility to, pro-\ngression of, and potential treatment targets for endometriosis. This chapter aims to \ncomprehensively analyze these genetic foundations through discussions on Genome-\nWide Association Studies (GW AS), candidate gene research, the interplay between \n\nA Comprehensive Overview of Endometriosis\n80\ngenetic susceptibility and environmental factors, and innovative technologies that are \nrevolutionizing our understanding of endometriosis [3].\nAlthough endometriosis is common and has a significant impact, its underlying \nmechanisms are still unknown, and trustworthy non-invasive diagnostic techniques are \ncurrently lacking. The gold standard for diagnosing endometriosis involves invasive sur-\ngical procedures like laparoscopy combined with confirmed histopathological examina -\ntion [4]. Due to the varied clinical presentations and the absence of precise non-invasive \ndiagnostic methods, it typically takes an average of seven to ten years duration from the \nonset of symptoms in patients to definitive diagnosis. The delays in diagnosis often exac -\nerbate symptoms, sometimes accelerate disease progression, and might have a negative \neffect on fertility , emphasizing the critical need for improved diagnostic methods [5].\nWhether cancer antigen 125 (CA125), a cancer antigen biomarker, can assist in \ndiagnosing endometriosis is not definitive. CA125 levels can fluctuate due to the \nmenstrual cycle phase, other female reproductive disorders (e.g., ovarian cysts, pelvic \ninflammatory diseases), and non-gynecological conditions (such as liver diseases). \nSo far, CA125 results must be considered alongside imaging examinations, clinical \nassessments, including other diagnostic techniques. Crucial research and clinical \nguidelines are preferentially needed to clearly show the CA125 roles in diagnosing and \nmanaging endometriosis [6].\nUnderstanding the genetic components of endometriosis provides a potential ave -\nnue for the enhanced diagnostics. Research on twins’ studies with familial aggregation \noffers compelling evidence for a significant genetic component involvement in endo -\nmetriosis. The raised risk observed in close relatives of affected women underscores the \ncrucial role of genetic factors associated with the development of such diseases [7].\nAdvances in genomic technologies, such as next-generation sequencing and \nGenome- Wide Association Studies (GW AS), have allowed for a more detailed \nexamination of the complex genetic structure of endometriosis. These studies help \nto identify variable genetic locations and disease-associated variants, offering a great \ninsight into its potential molecular pathways and enlightening better ways for non-\ninvasive diagnostics and genetic risk prediction computational models [8].\nLeveraging genetic knowledge to enhance diagnostic techniques could revolution-\nize endometriosis treatment. This approach anticipates a future for primary and cor-\nrect diagnostics enabling prompt interventions and specific personalized treatment \nplans for patients. Genetic classification of endometriosis patients might give rise to a \ntailored therapy , thereby improving better outcomes and quality of life for individuals \nwith endometriosis.\n1.1 Prevalence and impact\nEndometriosis is estimated to affect around 176 million women globally . It is a major \ncause of chronic pelvic pain and can lead to significant morbidity , affecting physical, \nmental, and social well-being. The economic burden of endometriosis is substantial, \nincluding both direct medical costs and indirect costs, such as loss of productivity .\n1.2 Staging of endometriosis\nEndometriosis is typically classified into four stages based on the severity and \nextent of the disease:\nStage I (Minimal): Small, superficial lesions and minimal involvement of pelvic \nstructures.\n\n81\nAdvances in Endometriosis Research: From Pathogenesis to Prevention\nDOI: http://dx.doi.org/10.5772/intechopen.1007830\nStage II (Mild): More extensive but still superficial implants and mild adhesions.\nStage III (Moderate): Presence of deep implants, small cysts on one or both ovaries, \nand some thick adhesions.\nStage IV (Severe): Extensive deep implants, large cysts on one or both ovaries, and \nmany dense adhesions.\n1.3 Global epidemiology and incidence\nEndometriosis is a prevalent gynecological condition affecting an estimated 10% \nof women of reproductive age worldwide. The incidence and prevalence of endome-\ntriosis can vary based on the population studied and the diagnostic criteria used [2]. \nKey points include:\n• Prevalence: The global prevalence of endometriosis is approximately 10%, but \nthis can range from 6 to 15% in various studies. In women with infertility , the \nprevalence is significantly higher, and it is reported to be between 20 and 40%.\n• Age of onset: Endometriosis most commonly affects women in their 30s and 40s, \nalthough symptoms can begin in adolescence.\n• Impact on health: It is associated with chronic pelvic pain, dysmenorrhea, and \ninfertility , which significantly impact the quality of life and socioeconomic status \nof affected women.\n• Healthcare burden: Endometriosis represents a substantial burden on healthcare \nsystems globally due to the chronic nature of the disease, diagnostic challenges, \nand long-term management needs.\nThis wide range reflects the variability in symptoms and the diagnostic challenges \nassociated with the disease.\n• United States: Studies suggest that about 6–10% of women of reproductive age are \naffected by endometriosis, equating to around 6.5 million women.\n• Europe : Prevalence rates in Europe are similar to those in the United States, with \nestimates ranging from 5 to 10% among women of reproductive age.\n• Asia : In Asian countries, prevalence rates range from 7 to 15%, with higher \nrates reported in countries with robust healthcare infrastructure and diagnostic \ncapabilities.\n•  Africa and South America: Data from these regions are limited, but available \nstudies indicate a prevalence of around 5–10%, similar to other parts of the \nworld.\n1.4 Incidence rate\n• The annual incidence rate of endometriosis varies, with estimates ranging from \n0.1 to 0.3% among women of reproductive age. The incidence rate is influenced \nby the awareness and diagnostic practices in different regions.\n\nA Comprehensive Overview of Endometriosis\n82\n• United Kingdom: The incidence rate is reported to be approximately 1.5 per 1000 \nwomen annually .\n• Japan : A study found an incidence rate of 0.2% per year among women aged \n20–29 years.\n• Australia : Incidence rates are estimated to be around 0.1–0.2% per year among \nwomen aged 15–49 years.\n1.5 V ariations in prevalence and incidence\nSeveral factors contribute to the variation in prevalence and incidence rates across \ndifferent regions:\n• Diagnostic practices : Regions with advanced healthcare systems and heightened \nawareness of endometriosis may report higher prevalence rates due to better \ndiagnostic capabilities.\n• Socioeconomic factors: Access to healthcare and socioeconomic status can influ-\nence the likelihood of receiving a diagnosis. W omen in low-income regions may \nhave limited access to diagnostic services.\n• Cultural factors: Cultural attitudes towards menstrual pain and women’ s health \ncan impact the reporting and diagnosis of endometriosis.\n• Genetic predisposition and environmental factors: Genetic predisposition and \nenvironmental factors, such as diet and lifestyle, may also contribute to regional \ndifferences in prevalence and incidence.\n1.6 Epidemiology and incidence in India\nEndometriosis is also a significant health issue in India, with prevalence rates \nsimilar to those seen globally . Specific data points from Indian studies include [9]:\n• Prevalence: Studies suggest a prevalence rate of about 10% among women of \nreproductive age in India, with higher rates observed in women presenting with \ninfertility or chronic pelvic pain.\n•  Age distribution : Endometriosis in Indian women typically presents in the 25–35 age \ngroup, though cases in adolescents and post-menopausal women are also reported.\n•  Diagnostic delays: There is often a delay in diagnosis, averaging 7–10 years from the \nonset of symptoms to a confirmed diagnosis, similar to global trends. Cultural fac -\ntors and limited access to specialized healthcare can contribute to this delay .\n• Regional variations: There may be regional differences in the reported incidence \nand prevalence, influenced by variations in healthcare access, awareness, and \ndiagnostic capabilities.\n• Healthcare impact: In India, endometriosis contributes significantly to gyneco-\nlogical morbidity and poses a considerable challenge to healthcare providers due \nto the chronic and recurrent nature of the condition.\n\n83\nAdvances in Endometriosis Research: From Pathogenesis to Prevention\nDOI: http://dx.doi.org/10.5772/intechopen.1007830\n2.  Genetic susceptibility and disease progression\n2.1 Genome-wide association studies (GW AS)\nGW AS have been instrumental in identifying genetic variants associated with \nendometriosis. These studies analyze the entire genome of individuals to find com-\nmon genetic variants that occur more frequently in those with the disease compared \nto those without. Key GW AS findings have identified several loci that are significantly \nassociated with endometriosis risk (Table  1) [18].\n2.2 Notable GW AS findings\n1. Chromosome 1p36: One of the earliest and most replicated findings is the as-\nsociation of endometriosis with the region on chromosome 1p36. Several genes \nwithin this region, including WNT 4 (Wnt Family Member 4), were found to \nbe implicated in the pathogenesis of endometriosis. WNT 4 has a crucial role in \nthe development of female reproductive system and its dysregulation has been \nlinked to endometriosis [19].\n2. Chromosome 7p15.2: This locus includes the gene nuclear factor-like factor 3 \n(NFE2L3), which is involved in the regulation of oxidative stress responses. \nOxidative stress is a key factor in the inflammatory processes associated with \nendometriosis, suggesting a potential mechanism by which genetic variation in \nthis region may contribute to the disease [11].\n3. Chromosome 2q23.3: The gene GREB1, located in this region, is involved in \nhormone-responsive cellular growth and has been shown to be differentially \nexpressed in endometriotic lesions compared to normal endometrium. This sug -\ngests a role for GREB1 (growth regulating estrogen receptor binding 1) in the \nhormonal regulation of endometriosis [20].\n4. Chromosome 12q22: The region harbors the gene VEZT , which encodes a protein \ninvolved in cell adhesion. Disruption of cell adhesion mechanisms is a hallmark \nof endometriosis, implicating VEZT (vezatin, adherens junctions transmem-\nbrane protein) in the disease’ s etiology [21].\n2.3 Candidate gene studies\nIn addition to GW AS, candidate gene studies have focused on specific genes \nhypothesized to be involved in endometriosis based on their biological functions. \nThese studies have provided valuable insights into the molecular mechanisms under-\nlying endometriosis.\n2.4 Key candidate genes\n1. ESR1 and ESR2: Estrogen receptors alpha and beta (ESR1 and ESR2) are critical \nfor the regulation of estrogen signaling, which is a key driver of endometriosis. \nV ariants in these genes have been associated with altered risk and severity of \nendometriosis, highlighting their importance in disease  pathogenesis [22].\n\nA Comprehensive Overview of Endometriosis\n84\nChromosome \nposition\nLocus Position Nearest gene Risk nucleotide Non-risk nucleotide Effect size (OR \nor 95% CI)\nP-value Significant/ \nNon-significant\nAncestry\n1p36.12 1p36 rs7521902 W N T4 G A 1.20 (1.15–1.25) 2.1 × 10^-9 Significant European [10]\n7p1 5.2 7p1 5.2 rs12700667 NFE2L3 T C 1.19 (1.13–1.24) 1.3 × 10^-7 Significant European [11]\n2q23.3 2q23.3 rs6757804 GREB1 G A 1.13 (1.08–1.18) 4.7 × 10^-8 Significant European [12]\n12q22 12q22 rs10859871 VEZT T C 1.22 (1.17–1.28) 8.3 × 10^-10 Significant European [13]\n6p21.1 6p21.1 rs71575922 CCDC170/ESR1 G A 1.16 (1.10–1.23) 5.6 × 10^-6 Significant European [8]\n9p21.3 9p21.3 rs10167914 CDKN2B-AS1 T C 1.11 (1.05–1.17) 9.1 × 10^-7 Significant European [8]\n1q42.1 1q42.1 rs12037376 LINC00339 A G 1.10 (1.04–1.16) 3.4 × 10^-6 Significant European [14]\n4q12 4q12 rs58682372 FN1 C T 1.14 (1.09–1.20) 1.8 × 10^-7 Significant Mixed Ancestry \n[15]\n11p1 5.5 11p1 5.5 rs11031006 INS-IGF2 G A 1.20 (1.14–1.26) 2.5 × 10^-9 Significant European [16]\n5p15.33 5p15.33 rs2736100 TERT A G 1.17 (1.12–1.23) 7 .2 × 10^-8 Significant European [17]\nEffect size (OR or 95% CI): Odds ratio (OR) or 95% confidence interval (CI) representing the strength of the association between the genetic variant and endometriosis risk. P-value: Statistical \nsignificance of the association. Significant/Non-significant: Based on the p-value, typically p < 0.05 is considered significant. Ancestry: The population in which the study was conducted, \nprimarily European, with some studies including mixed ancestry groups.\nTable  1.  \nGenome- Wide Association Studies (GW AS) on endometriosis, including details, such as the chromosome position, locus, nearest gene, risk and non-risk nucleotides, effect size or \nconfidence interval, p-value, significance, and ancestry.\n\n85\nAdvances in Endometriosis Research: From Pathogenesis to Prevention\nDOI: http://dx.doi.org/10.5772/intechopen.1007830\n2. PGR: The progesterone receptor gene (PGR) has been implicated in endometriosis, \nparticularly in the context of progesterone resistance observed in endometriotic \ntissues. V ariants in PGR may contribute to the impaired response to progesterone, \nexacerbating the disease [23].\n3. MMPs: Matrix metalloproteinases (MMPs) are involved in the degradation of \nextracellular matrix components and tissue remodeling. Dysregulation of MMP \nexpression and activity has been observed in endometriosis, suggesting a role in \nthe invasive properties of endometrial cells [24].\n4. TNF and IL-1: Tumor necrosis factor (TNF) and interleukin-1 (IL-1) are \n pro-inflammatory cytokines that have been implicated in the inflamma -\ntory response associated with endometriosis. Genetic variants in these cyto-\nkines and their receptors may influence the severity and progression of the \n disease [25].\n2.5 Genetic and environmental factors’ interplay\nEndometriosis is a multifactorial disease, meaning that both genetic and environ-\nmental factors contribute to its development. The interplay between these factors is \ncomplex and not fully understood.\n2.6 Interaction between genetic and environmental factors\nThe interplay between genetic and environmental factors is complex and bidi-\nrectional. Genetic predisposition can influence an individual’ s sensitivity to environ-\nmental exposures, while environmental factors can modify gene expression through \nepigenetic mechanisms.\n• Gene-environment interaction: Individuals with certain genetic variants may \nbe more susceptible to environmental factors, such as exposure to endocrine-\ndisrupting chemicals (EDCs) or chronic inflammation. For example, polymor-\nphisms in genes involved in detoxification pathways might render individuals \nmore vulnerable to environmental toxins.\n• Epigenetic modulation: Environmental factors can lead to epigenetic changes \nthat alter the expression of genes implicated in endometriosis. For instance, \nexposure to dioxins can induce DNA methylation changes in genes regulating \nimmune response and cell proliferation, contributing to the development of \n endometriotic lesions.\n2.7 Mechanisms of epigenetic-environmental interaction\n1. DNA methylation: Environmental factors, such as exposure to endocrine-\ndisrupting chemicals (EDCs) like bisphenol A (BP A), can cause aberrant DNA \nmethylation. For example, BP A exposure has been shown to alter the methyla -\ntion of genes involved in estrogen signaling pathways, potentially increasing the \nrisk of developing endometriosis.\n2. Histone modification: Nutritional factors, such as a high-fat diet, can influence \nhistone acetylation and methylation. Diet-induced changes in histone modi-\n\nA Comprehensive Overview of Endometriosis\n86\nfications can affect genes that regulate inflammation and cell proliferation, \npotentially promoting the establishment and progression of endometriotic \nlesions.\n3. Non-coding RNA regulation: Environmental stressors, such as oxidative stress \nfrom pollution, can alter the expression of microRNAs (miRNAs) and long non-\ncoding RNAs (lncRNAs). These non-coding RNAs can modulate the expression \nof genes involved in inflammatory responses and tissue remodeling, contribut -\ning to the pathogenesis of endometriosis.\n2.8 Epigenetic modifications\nEpigenetic changes, such as DNA methylation and histone modifications, can \nalter gene expression without changing the underlying DNA sequence. The modifica -\ntions are influenced by environmental factors and might play a significant role in the \ndevelopment of endometriosis disease [26].\n1. DNA methylation: Aberrant DNA methylation patterns have been observed in \nendometriotic tissues. Hypermethylation of genes involved in immune response \nand inflammation, such as HOXA10 (Homeobox A10) and E-cadherin, may \ncontribute to the pathogenesis of endometriosis [27].\n2. Histone modifications in epigenetic regulation of endometriosis: Histone acetyla -\ntion and methylation can also influence gene expression. Changes in histone \nmodification patterns have been linked to the regulation of genes involved in cell \nproliferation and inflammation in endometriosis (Table  2) [28].\nHistone \nmodification\nSpecific \nmodification\nAssociated enzymes Role in endometriosis References\nHistone \nacetylation\nH3K9ac, \nH3K27ac\nHATs (e.g., p300, CBP), \nHDACs (e.g., HDAC1, \nHDAC2)\nDysregulated acetylation \nlinked to aberrant gene \nexpression and inflammation \nin endometriotic lesions\n[28]\nHistone \nmethylation\nH3K4me3, \nH3K9me2, \nH3K27me3\nMethyltransferases \n(e.g., SETD1, EZH2), \nDemethylases (e.g., \nKDM1A, KDM5B)\nAberrant methylation \npatterns associated with \naltered cell proliferation, \ndifferentiation, and immune \nresponse in endometriosis\n[27]\nHistone \nphosphorylation\nH3S10ph, \nH3T3ph\nKinases (e.g., Aurora B \nkinase), Phosphatases\nLinked to changes in \nchromatin structure and \ngene expression during \nendometriosis progression\n[12]\nHistone \nubiquitination\nH2Aub, H2Bub E3 ligases (e.g., \nRNF20/40), \nDeubiquitinases\nInvolved in the regulation \nof DNA damage response \nand transcription in \nendometriosis\n[29]\nTable 2. \nDifferent types of histone modifications are implicated in the epigenetic control of endometriosis, encompassing \nhistone acetylation, methylation, phosphorylation, and ubiquitination.\n\n87\nAdvances in Endometriosis Research: From Pathogenesis to Prevention\nDOI: http://dx.doi.org/10.5772/intechopen.1007830\n3.  Key histone modifications\n3.1 Histone acetylation\nHistone acetylation typically occurs on lysine residues in histone tails and is associated \nwith an open chromatin structure and active gene transcription. Histone acetyltransfer-\nases (HATs) add acetyl groups, while histone deacetylases (HDACs) remove them.\n• HATs in endometriosis: Increased activity of HATs has been observed in endome-\ntriotic tissues, leading to hyperacetylation of histones and upregulation of genes \ninvolved in cell proliferation and survival.\n• HDACs in endometriosis: Conversely , the expression and activity of certain \nHDACs are altered in endometriosis. Inhibiting HDACs has shown promise in \nreducing the proliferation of endometriotic cells and inducing apoptosis, sug -\ngesting potential therapeutic avenues [30].\n3.2 Histone methylation\nHistone methylation can activate or repress gene expression depending on the \nspecific amino acids that are methylated and the number of methyl groups added \n(mono-, di-, or tri-methylation).\n• H3K4 methylation: Trimethylation of histone H3 at lysine 4 (H3K4me3) is \ngenerally associated with active transcription. In endometriosis, altered levels \nof H3K4me3 have been linked to the aberrant expression of genes involved in \ninflammation and cell cycle regulation.\n• H3K27 methylation: Trimethylation of histone H3 at lysine 27 (H3K27me3) is \nassociated with gene repression. Dysregulation of H3K27me3 has been noted \nin endometriotic lesions, impacting genes that regulate cell differentiation and \nimmune response [31].\n3.3 Histone phosphorylation\nHistone phosphorylation is involved in chromatin remodeling and gene expression \nin response to various cellular signals, such as DNA damage and stress.\n• H3S10 phosphorylation: Phosphorylation of histone H3 at serine 10 (H3S10ph) \nhas been linked to chromatin condensation and transcriptional activation. In \nendometriosis, aberrant H3S10ph levels have been observed, particularly in \ngenes related to cell proliferation and survival [32].\n• H3T3 phosphorylation: Phosphorylation of histone H3 at threonine 3 (H3T3ph) \nplays a critical role in chromatin dynamics during cell division, particularly in \nchromosome segregation and condensation. This modification is catalyzed by \nthe Aurora B kinase as part of the chromosomal passenger complex.\nIn endometriosis, aberrant H3T3ph has been associated with dysregulated cell \ndivision, contributing to the proliferation of ectopic endometrial tissue. Elevated \n\nA Comprehensive Overview of Endometriosis\n88\nlevels of H3T3 phosphorylation in endometriotic lesions have been observed, \nimplicating this modification in disease progression by enhancing mitotic activ -\nity and genomic instability .\n3.4 Histone ubiquitination\nHistone ubiquitination involves the addition of ubiquitin molecules to histone \nproteins, often marking them for degradation or altering their interaction with other \nchromatin components.\n•  H2A and H2B ubiquitination: Ubiquitination of histones H2A and H2B \n(H2Aub) and (H2Bub) plays roles in DNA repair and transcriptional regu-\nlation. Changes in histone ubiquitination patterns have been reported in \nendometriosis, influencing gene expression profiles associated with disease \npathogenesis [29].\n3.5 Impact on gene regulation\nHistone modifications in endometriosis lead to the dysregulation of key genes \ninvolved in various cellular processes, including:\n• Inflammation: Epigenetic alterations in histone modifications can upregulate \ninflammatory cytokines and chemokines, contributing to the chronic inflamma -\ntory environment characteristic of endometriosis.\n• Cell proliferation and survival: Dysregulated histone modifications can activate \ngenes that promote cell proliferation and inhibit apoptosis, facilitating the \ngrowth and persistence of endometriotic lesions.\n• Immune response: Changes in histone modifications can affect the expression \nof genes involved in immune surveillance and response, potentially leading to \nimmune evasion by endometriotic cells.\n3.6 Therapeutic implications\nTargeting histone modifications offers a promising strategy for the treatment of \nendometriosis. Potential therapeutic approaches include:\n•  HDAC inhibitors: Inhibitors of histone deacetylases have shown potential \nin reducing the growth of endometriotic lesions and alleviating symptoms. \nThese inhibitors can restore the balance of histone acetylation, leading to \nthe re-expression of suppressed genes and the induction of apoptosis in \n endometriotic cells.\n• Histone methyltransferase and demethylase inhibitors: Modulating the activity of \nenzymes involved in histone methylation, such as histone methyltransferases \n(HMTs) and demethylases (HDMs), can correct aberrant methylation patterns \nand normalize gene expression [31].\n\n89\nAdvances in Endometriosis Research: From Pathogenesis to Prevention\nDOI: http://dx.doi.org/10.5772/intechopen.1007830\n• Current clinical trials\nSeveral clinical trials are actively investigating new therapeutic approaches for \nendometriosis.\nNCT03080521: A phase II trial evaluating the efficacy of linzagolix, a novel oral \ngonadotropin-releasing hormone (GnRH) antagonist, in reducing pain associ-\nated with endometriosis [33].\nNCT03386867: This study is testing the combination of anastrozole, an aromatase \ninhibitor, with norethindrone acetate, a progestin, in treating endometriosis-\nassociated pain [34].\nNCT03697090:  A trial exploring the use of cannabidiol (CBD), a non-psycho-\nactive component of cannabis, for its potential anti-inflammatory and pain-\nrelieving properties in endometriosis [35].\nNCT04015432: This study investigates the use of NT100, a recombinant human \nplatelet-derived growth factor, for its regenerative properties in women with \nendometriosis-related infertility [36].\nNCT04100668: A trial assessing the safety and efficacy of relugolix, another \noral GnRH antagonist, in women with moderate to severe endometriosis \npain [37].\n3.7 Studying epigenetic changes\nStudying epigenetic changes in endometriosis has yielded significant insights into \nthe disease’ s pathogenesis. Recent research has focused on histone modifications and \nDNA methylation, highlighting their roles in aberrant gene expression corresponding \nto endometriosis. For instance, Guo et  al. [38] in their study identified differential \nDNA methylation patterns in an endometriotic tissue, particularly hypermethylation \nof the HOXA10 promoter, which is linked to impaired implantation and infertil-\nity . Similarly , a study by Y otova et  al. [39] examined histone acetylation and found \nincreased H3K27ac (histone H3 lysine 27 acetylation) levels in endometriotic lesions, \ncorrelating with upregulated pro-inflammatory genes.\nAnother notable investigation by Zhang et  al. [40] explored the role of histone \nmethylation, discovering that elevated H3K27me3 in ectopic endometrial tissue sup-\npresses genes involved in apoptosis, facilitating the survival of endometriotic cells. \nFurthermore, the work of Suganuma et  al. [41] on miRNA-mediated regulation of \ngene expression demonstrated that microRNA-451a (miR-451a) downregulation leads \nto enhanced expression of matrix metalloproteinase-9 (MMP-9), contributing to the \ninvasive properties of endometriotic cells.\nWhile these findings are promising, several limitations and challenges hinder their \ntranslation into clinical practice:\n1. Complexity of epigenetic regulation: The regulation of gene expression through \nepigenetic modifications is complex and multifactorial. It involves not only DNA \nmethylation and histone modifications but also non-coding RNAs and chromatin \n\nA Comprehensive Overview of Endometriosis\n90\nremodeling. This complexity makes it challenging to pinpoint specific targets for \ntherapeutic intervention.\n2. Heterogeneity of endometriosis: Endometriosis is a heterogeneous disease with \nvarying presentations and severities. Epigenetic studies often focus on spe-\ncific lesions or tissue samples, which may not fully capture the diversity of the \ndisease. This heterogeneity can lead to inconsistent findings and complicate the \ndevelopment of broadly applicable treatments.\n3. Sample variability: Epigenetic studies typically require high-quality tissue sam-\nples, which can be difficult to obtain. Differences in sample processing, storage, \nand analysis can introduce variability and affect the reproducibility of results. \nMoreover, the need for invasive procedures to obtain tissue samples limits the \nfeasibility of large-scale studies.\n4. Dynamic nature of epigenetic changes: Epigenetic modifications are dynamic \nand can be influenced by various factors, including environmental exposures, \nhormonal changes, and disease progression. This dynamism poses a challenge \nin distinguishing causal changes from those that are secondary to the disease \nprocess.\n5. Translational gap: Despite the identification of epigenetic alterations in endo-\nmetriosis, translating these findings into clinical practice remains a significant \nchallenge. Potential therapies targeting epigenetic modifications must undergo \nrigorous testing for safety and efficacy . Additionally , developing non-invasive \nbiomarkers based on epigenetic changes for early diagnosis and monitoring \nrequires further validation.\n4.  Environmental factors\nSeveral environmental factors have been associated with an increased risk of \ndeveloping endometriosis. These factors may interact with genetic predispositions to \ninfluence disease onset and progression (Table  3).\nCategory Candidate genes/Pathways/\nPolygenic risk scores/Biomarkers\nKey findings/ Association References\nCandidate genes ESR1, ESR2, PGR, MMPs, TNF , IL-1, \nHOXA10, CDKN2B-AS1\nV ariants associated with altered \nrisk and severity of endometriosis\n[42]\nPathways Estrogen signaling, Progesterone \nresistance, Inflammation\nDysregulation implicated in \nendometriosis pathogenesis\n[22]\nPolygenic risk \nscores\nGenome-wide Risk Scores (GRS) Aggregate genetic risk associated \nwith increased endometriosis risk\n[43]\nBiomarkers DNA methylation (HOXA10, \nE-cadherin), miRNAs, Inflammatory \nmarkers\nAltered expression patterns in \nendometriosis patients\n[44]\nTable  3. \nCandidate gene studies, pathways, polygenic risk scores, and biomarkers associated with endometriosis.\n\n91\nAdvances in Endometriosis Research: From Pathogenesis to Prevention\nDOI: http://dx.doi.org/10.5772/intechopen.1007830\n1. Hormonal factors: Exposure to endogenous and exogenous hormones, such as \nestrogen, plays a significant and crucial role in the development of endometrio-\nsis disease. Genetic variants that affect hormone metabolism and signaling may \nmodulate the impact of hormonal exposures.\nInteraction with genetic predispositions:\nEstrogen receptor genes: Genetic variants in estrogen receptor genes (e.g., ESR1, \nESR2) can increase sensitivity to hormonal fluctuations. This heightened sen-\nsitivity may exacerbate the impact of environmental estrogen exposure from \nhormone replacement therapy , contraceptives, or xenoestrogens (environmental \nestrogens) found in plastics and pesticides.\nEpigenetic changes: Estrogen receptor binding can lead to changes in DNA methyla -\ntion and histone modification, which affect gene expression. Estrogen can cause \nhypermethylation or hypomethylation of genes involved in cell proliferation and \napoptosis, influencing disease progression in genetically predisposed individuals.\n2. Immune system dysregulation: The immune system also plays a major role in the \npathogenesis of endometriosis. Genetic variants that directly or indirectly affect \nimmune function may interact with environmental factors (such as infections or \nstress) and further influence the development of disease.\nInteraction with genetic predispositions.\nCytokine genes: Genetic variants in cytokine genes (e.g., Interleukin-1 (IL-1), \ninterleukin 6 (IL-6), tumor necrosis factor alpha (TNF-α)) can result in height -\nened inflammatory responses. When exposed to environmental toxins, individu-\nals with these variants may experience exaggerated immune reactions, promot -\ning the establishment and growth of endometriotic lesions.\nDetoxification genes: V ariants in genes responsible for detoxifying environmental \ntoxins (e.g., glutathione S-transferase M1 (GSTM1), glutathione S-transferase \ntheta-1 (GSTT1)) may reduce the efficiency of toxin elimination, increasing \nsusceptibility to immune dysregulation and inflammation.\n3. Lifestyle factors: Diet, physical activity , and exposure to environmental toxins, such \nas dioxins, have been implicated in the risk of endometriosis. These factors may af -\nfect the expression of genes involved in inflammatory and metabolic pathways [45].\nInteraction with genetic predispositions.\nMetabolic genes: Genetic variants in metabolic genes (e.g., CYP19 A1 (Cytochrome \np450 family 19 subfamily A member 1), COMT (catechol-O-methyltransferase)) \naffect how individuals process dietary fats and metabolize estrogen. High-fat \ndiets can alter estrogen metabolism, leading to higher circulating estrogen levels, \nwhich can exacerbate endometriosis in genetically predisposed individuals.\nStress response genes: V ariants in stress response genes (e.g., NR3C1 (nuclear \nreceptor subfamily 3 group C member 1), FKBP5 (FK506-binding protein 5)) \ncan affect cortisol levels and stress resilience. Chronic stress can induce epigen-\netic changes, such as DNA methylation and histone modification, impacting the \nexpression of genes involved in inflammation and immune response.\n\nA Comprehensive Overview of Endometriosis\n92\n   5.  Endometriosis-related signaling pathways \n In endometriosis, estrogen signaling is often dysregulated, leading to abnormal \nproliferation and survival of endometrial-like tissue outside the uterus. Progesterone \nresistance in endometrial lesions contributes to the persistence and growth of these \ntissues, despite normal hormonal levels [ 46 ]. Inflammatory cytokines are elevated, \nexacerbating the chronic inflammation and promoting pain and lesion development. \nAngiogenesis is increased, providing a vascular supply that supports the growth of \nendometrial implants. Oxidative stress, due to heightened reactive oxygen species \n(ROS), damages tissues and further inflames the environment. Epithelial-mesenchymal \ntransition (EMT) is disrupted, enhancing the invasive potential of endometrial cells. \nImmune dysregulation results in impaired immune surveillance and clearance of ectopic \ntissues. Fibrosis occurs as a result of persistent inflammation and tissue damage, leading \nto scar tissue formation. Histone modifications are altered, affecting gene expression and \npotentially contributing to the disease’ s progression. \n  Figure 1.\n  This figure illustrates the three major MAPK signaling pathways: ERK, JNK, and p38. Each pathway is activated \nby different external stimuli through receptor-mediated mechanisms, leading to a cascade of phosphorylation \nevents that result in various cellular responses. The ERK pathway, primarily associated with cell proliferation \nand differentiation, involves components, such as rapidly accelerated fibrosarcoma (RAF), human MAPK \nkinase kinases 1/2 (MEK1/2), and ERK. The JNK pathway, linked to stress responses, includes mitogen-activated \nprotein kinase/ERK kinase kinase (MEKK), MAPK kinases 4/7 (MKK4/7), and JNK. The p38 pathway, also \nrelated to stress responses, involves TGF-β-activated kinase (T AK), MAPK kinases 3/6 (MKK3/6), and p38 Figure \nassembled and created using  BioRender .com .          \n\n93\nAdvances in Endometriosis Research: From Pathogenesis to Prevention\nDOI: http://dx.doi.org/10.5772/intechopen.1007830\n  5.1 MAPK-related pathways \n The mitogen-activated protein kinase (MAPK) pathways are pivotal in regulating \ncell proliferation, differentiation, and apoptosis. In the context of endometriosis, the \nabnormal activation of MAPK pathways, specifically extracellular signal-regulated \nkinase (ERK), Jun N-terminal kinase (JNK), and p38 pathways, promotes the survival \nand proliferation of endometrial cells located outside the uterus. These pathways are \noften activated by growth factors and cytokines, leading to enhanced cellular responses \nthat support the establishment and maintenance of endometriotic lesions   Figure 1   [  4 7  ] .   \n  Figure 2.\n  This figure illustrates the mTOR/PI3K/Akt signaling pathway, highlighting its role in cell growth, proliferation, \nsurvival, and cytoskeletal organization. The pathway is activated by various stimuli, such as glucose, amino \nacids, growth factors, and insulin. Key components include PI3K, Akt, tuberous sclerosis complexes 1 and 2 \n(TSC1/2), mammalian target of rapamycin complex 1 (mTORC1), and mammalian target of rapamycin \ncomplex 2 (mTORC2). PI3K/Akt/mTOR pathway is assembled and created using  BioRender .com .          \n\nA Comprehensive Overview of Endometriosis\n94\n5.2 PI3K/mTOR/ Akt/related pathways\nThe phosphatidylinositol 3- kinase/mammalian target of rapamycin/protein \nkinase B (PI3K/mTOR/Akt) pathway is essential for regulating cell growth, survival, \nand metabolism. In endometriosis, this pathway is frequently disrupted, leading to \nenhanced cell survival, angiogenesis, and resistance to apoptosis in endometriotic tis-\nsues. Activation of PI3K/mTOR/Akt signaling in endometriosis is often triggered by \ngrowth factors and inflammatory cytokines, which contribute to the pathophysiology \nof the disease by enhancing cellular proliferation and survival (Figure  2) [47].\n5.3 NF-κB pathway\nThe nuclear factor kappa B (NF-κB) pathway has a pivotal role in inflammation \nand immune response control. In endometriosis, NF-κB is persistently activated, \nresulting in the secretion of pro-inflammatory cytokines, chemokines, and adhesion \nmolecules. This ongoing inflammatory reaction supports the attachment and growth \nof endometrial cells in abnormal sites, sustaining a cycle of inflammation and tissue \nrestructuring (Figure  3) [48].\n5.4 Hippo/yes-associated protein (Y AP) and autophagy\nThe Hippo/Y AP pathway , which governs organ size and cell proliferation, addi-\ntionally impacts autophagy , a process involving the breakdown and recycling of \nFigure  3. \nThe NF-κB signaling pathway is a critical mechanism in immunology that regulates gene expression involved in \nimmune responses and inflammation. NF-κB acts as a transcription factor , controlling the production of proteins \nthat mediate immune and inflammatory reactions. This pathway is essential for the proper functioning of the \nimmune system and plays a role in various diseases associated with dysregulated immune responses. Pathway is \nassembled and created using BioRender .com.\n\n95\nAdvances in Endometriosis Research: From Pathogenesis to Prevention\nDOI: http://dx.doi.org/10.5772/intechopen.1007830\ncellular components. In endometriosis, disruptions in the Hippo/Y AP pathway and \nautophagy mechanisms promote cell proliferation, survival, and resistance to apopto-\nsis, thereby supporting the persistence of endometriotic lesions [49].\n5.5 ROS and metabolic processes\nReactive oxygen species (ROS) and altered metabolic processes are significant con-\ntributors to the pathogenesis of endometriosis. Elevated levels of ROS in endometriotic \ncells lead to oxidative stress, DNA damage, and altered cellular functions. These changes \nenhance cell survival, proliferation, and inflammatory responses, creating a favorable \nenvironment for endometrial cells to thrive outside the uterus [50, 51].\n5.6 Wnt/β-catenin signaling pathway\nThe Wnt / β-catenin signaling pathway is crucial for cell proliferation, migration, \nand differentiation. In endometriosis, aberrant activation of Wnt/β-catenin signal-\ning promotes the proliferation and invasion of endometrial cells. This pathway also \ninteracts with other signaling mechanisms, contributing to the complex molecular \nlandscape that supports the growth of endometriotic lesions [52].\n5.7 Rho/ROCK\nThe Rho/ROCK (Rho-associated protein kinase) pathway regulates cytoskel-\netal dynamics, cell migration, and adhesion. In endometriosis, enhanced Rho/\nROCK signaling facilitates the migration and invasion of endometrial cells into \nectopic sites. This pathway also influences the production of extracellular matrix \ncomponents, aiding in the establishment and maintenance of endometriotic \nlesions [53].\n5.8 TGF-β-mediated pathways\nTransforming growth factor-beta (TGF-β)-mediated pathways are involved in \nregulating cell growth, differentiation, and immune responses. In endometriosis, \nTGF-β signaling is often upregulated, leading to increased fibrosis, angiogenesis, and \nimmune suppression. These effects contribute to the chronic and progressive nature \nof the disease by promoting tissue remodeling and creating a supportive microenvi-\nronment for endometrial cells [54].\n5.9 VEGF\nV ascular endothelial growth factor (VEGF) is a key regulator of angiogenesis. In \nendometriosis, elevated levels of VEGF promote the formation of new blood vessels, \nensuring an adequate blood supply to endometriotic lesions. This angiogenic response \nis essential for the survival and growth of ectopic endometrial tissues, facilitating \ntheir persistence and expansion (Figure  4) [38].\n5.10 NO-mediated pathway and iron-mediated pathway\nNitric oxide (NO) and iron play significant roles in the pathophysiology of endo-\nmetriosis. NO-mediated pathways influence vasodilation, immune responses, and cell \n\nA Comprehensive Overview of Endometriosis\n96\nsignaling, while iron, released from hemoglobin breakdown in endometriotic lesions, \ncan catalyze the formation of ROS. Both NO and iron contribute to the inflammatory \nand oxidative stress environment in endometriosis, exacerbating tissue damage and \npromoting lesion development [ 55 ].  \n  5.11 Macrophages, cytokines, and the immune system \n The immune system, particularly macrophages and cytokines, is deeply \ninvolved in the development and progression of endometriosis. Macrophages \ninfiltrate endometriotic lesions and secrete pro-inflammatory cytokines, growth \nfactors, and enzymes that support lesion growth and survival. The chronic inflam-\nmation mediated by these immune cells creates a feedback loop that perpetuates \nthe disease state, contributing to pain and infertility associated with endometriosis \n (  Table 4  )  [  7 1  ] .   \n  Figure 4.\n  This figure depicts the VEGF (vascular endothelial growth factor) signaling pathway, highlighting its role in \nangiogenesis. VEGF binds to its receptor on endothelial cells, activating multiple downstream signaling cascades. \nVEGF signaling pathway is assembled using dynamic BioRender assets.          \n\n97\nAdvances in Endometriosis Research: From Pathogenesis to Prevention\nDOI: http://dx.doi.org/10.5772/intechopen.1007830\nPathways or molecules Effect on EMs Pathophysiology In vivo/vitro Species Key molecules References\nEstrogen signaling Promotes cell proliferation Increased local estrogen production In vivo, In vitro Human, \nMouse\nESR1, ESR2, Aromatase [56, 57]\nProgesterone resistance Reduces differentiation, \nincreases survival\nResistance to apoptosis, increased \nproliferation\nIn vivo, In vitro Human, \nMouse\nPGR, HOXA10 [58, 59]\nInflammatory cytokines Promotes inflammation and \npain\nChronic inflammation, pain In vivo, In vitro Human IL-1, IL-6, TNF-α [56, 60]\nAngiogenesis Promotes lesion vascularization Increased blood vessel formation In vivo, In vitro Human, \nMouse\nVEGF , ANGPT1, ANGPT2 [61, 62]\nOxidative stress Enhances cell survival and \ninvasion\nROS-mediated cell damage and \ninvasion\nIn vivo, In vitro Human ROS, SOD2, GPX3 [63, 64]\nEpithelial-mesenchymal \ntransition (EMT)\nIncreases invasiveness Loss of epithelial characteristics In vitro Human N-cadherin, E-cadherin, \nVimentin\n[41, 65]\nImmune dysregulation Impairs immune response Altered immune cell function, \nimmune evasion\nIn vivo, In vitro Human NK cells, Macrophages [39, 66]\nFibrosis Promotes tissue scarring Excessive collagen deposition, \nfibrosis\nIn vivo, In vitro Human TGF-β , Collagen [67 , 68]\nHistone modifications Alters gene expression Epigenetic regulation, gene \nsilencing/activation\nIn vitro Human HATs, HDACs, HMTs, \nHDMs\n[69, 70]\nTable  4.  \nSignaling pathways and molecules involved in the pathophysiology of endometriosis, including their effects on endometriosis (EMs), the pathophysiological mechanisms, in vivo or in \nvitro models, species studied, and key molecules involved.\n\nA Comprehensive Overview of Endometriosis\n98\n6.  Emerging technologies and methodologies\nAdvances in technology have revolutionized the study of the genetic basis of \nendometriosis. These emerging technologies and methodologies are providing new \ninsights into the complexity of the disease.\n6.1 Next-generation sequencing (NGS)\nNext-generation sequencing (NGS) has greatly enhanced our comprehension of \nthe genetic makeup of endometriosis. This technology enables thorough examina -\ntion of the entire genome or specific regions, facilitating the detection of rare genetic \nvariations and mutations.\n1. Whole-genome sequencing (WGS): WGS provides a complete picture of an indi-\nvidual’ s genetic makeup. This approach has been used to identify novel genetic \nvariants associated with endometriosis, including rare variants that may have \nlarge effects on disease risk.\nIdentification of novel genetic variants: Researchers are using WGS to discover rare \ngenetic variants associated with endometriosis. For example, WGS has revealed \npreviously unidentified genetic alterations that could contribute to disease sus-\nceptibility . Studies have linked certain novel variants to the regulation of inflam-\nmatory responses and cell proliferation, which are critical in endometriosis.\nUnderstanding genetic interactions: WGS helps in mapping out complex genetic \ninteractions and identifying genetic factors that may influence disease severity \nor response to treatment. This comprehensive approach provides insights into \nthe polygenic nature of endometriosis.\n2. Whole exome sequencing (WES): WES focuses on the protein-coding regions of \nthe genome, which are most likely to contain disease-causing mutations. This \nmethod has identified several novel candidate genes for endometriosis, including \nthose involved in immune response and cell adhesion.\nDiscovery of disease-causing mutations: WES focuses on the protein-coding regions \nof the genome, which are often where disease-causing mutations reside. Re-\nsearch utilizing WES has identified new candidate genes involved in endome-\ntriosis, such as those related to immune system function and cell adhesion. These \nfindings help in understanding the pathogenesis of the disease and identifying \npotential therapeutic targets.\nGenetic variation and drug response: WES is also being used to study how genetic \nvariations affect the efficacy and safety of treatments. By correlating specific \nmutations with treatment outcomes, researchers aim to develop personalized \nmedicine approaches for endometriosis.\n6.2 Functional genomics\nFunctional genomics aims to understand the genetic variants’ functional implica -\ntions and their respective roles in disease pathogenesis. This field combines genomic \ndata with experimental approaches to study gene function and regulation.\n\n99\nAdvances in Endometriosis Research: From Pathogenesis to Prevention\nDOI: http://dx.doi.org/10.5772/intechopen.1007830\n1. CRISPR-Cas9: The CRISPR-Cas9 (clustered regularly interspaced palindromic \nrepeats/CRISPR-associated protein 9) gene-editing technology allows for precise \nmodification of specific genes. This tool has been used to investigate the role of \ncandidate genes in endometriosis by creating knockout models in cell lines and \nanimal models.\n2. Transcriptomics : Transcriptomic studies analyze gene expression profiles to \nunderstand the molecular pathways involved in endometriosis. RNA sequencing \n(RNA-seq) has revealed differential expression of genes involved in inflamma -\ntion, hormone signaling, and immune response in endometriotic tissues.\n3. Proteomics and metabolomics: These approaches study the protein and metabolite \nprofiles associated with endometriosis. Proteomic and metabolomic analyses \nhave identified biomarkers and pathways that may be targeted for therapeutic \ninterventions.\n6.3 Implications for personalized medicine\nThe insights gained from genetic research have significant implications for person-\nalized diagnosis, treatment, and prevention strategies in endometriosis management.\n6.3.1 Personalized diagnosis\nGenetic and molecular profiling can enhance the accuracy of the diagnosis of endo-\nmetriosis. Biomarkers identified through genetic studies can be used to develop non-\ninvasive diagnostic tests, reducing the need for invasive procedures like laparoscopy .\n1. Genetic biomarkers: Genetic variants associated with the risk of endometriosis \ndisease might serve as early disease detection biomarkers. For example, the \nWNT 4 and GREB1 gene variants could be included in genetic panels to identify \nindividuals at higher risk.\n2. Epigenetic biomarkers: DNA methylation patterns and histone modifications spe-\ncific to endometriosis can also be used as diagnostic markers. These epigenetic \nchanges are detected in patients’ samples of blood and tissue, thus providing a \nnon-invasive diagnostic tool [72].\n6.3.2 Personalized treatment\nUnderstanding the genetic basis of endometriosis can lead to the development of \ntargeted therapies that are tailored to an individual’ s genetic profile.\n1. Hormonal therapies: Genetic variants in hormone receptors and signaling path-\nways can influence an individual’ s response to hormonal treatments. Personal-\nized hormonal therapies can be designed based on the patient’ s genetic profile to \nimprove efficacy and reduce side effects.\nGenetic variants in hormone receptors: V ariants in genes encoding estrogen and \nprogesterone receptors can influence how patients respond to hormonal treat -\nments. Personalized hormonal therapies, such as specific estrogen receptor \n\nA Comprehensive Overview of Endometriosis\n100\n modulators or selective progesterone receptor modulators, can be designed based \non these genetic profiles to enhance treatment efficacy and minimize side effects.\nPharmacogenomics: Research is being conducted to understand how genetic \nvariations affect responses to common hormonal treatments like GnRH agonists \nor oral contraceptives. This can le ad to personalized treatment regimens that are more \neffective for individual patients.\n2. Anti-inflammatory agents: Inflammation is a key component of the pathogenesis of \nendometriosis. Genetic variants in inflammatory pathways can guide the use of anti-\ninflammatory agents to target specific molecular mechanisms involved in the disease.\nT argeted anti-inflammatory therapies: Genetic variants in inflammation-related \ngenes, such as TNF-α and IL-6, can influence the effectiveness of anti-inflamma -\ntory treatments. Personalized anti-inflammatory therapies, like TNF inhibitors \nor IL-6 receptor antagonists, may be tailored to target specific inflammatory \npathways involved in endometriosis.\n3. Immunomodulatory therapies: Genetic insights into immune dysregulation in \nendometriosis can inform the development of immunomodulatory therapies. For \nexample, targeting specific cytokines or immune cells implicated in endometrio-\nsis may provide more effective treatment options.\nCytokine targeting: Genetic insights into immune dysregulation in endometriosis \ncan inform the development of therapies targeting specific cytokines. For instance, \ninterleukin 1 beta (IL-1β ) inhibitors or interleukin 10 (IL-10)-based therapies are \nbeing explored to modulate the immune response and reduce disease symptoms.\nMonoclonal antibodies: Monoclonal antibodies targeting specific immune cells or \npathways, such as anti-IL-6 or anti- TNF-α antibodies, are under development as \npersonalized treatments based on individual genetic and immune profiles [73].\n6.4 Prevention strategies\nGenetic research can also inform prevention strategies for endometriosis by identi -\nfying individuals at risk and implementing early interventions.\n1. Risk prediction models: By integrating genetic, environmental, and clinical data, \nrisk prediction models can be developed to identify individuals with a height -\nened risk of developing endometriosis. These models can inform preventive \nstrategies and early monitoring efforts.\n2. Lifestyle interventions: Understanding the interplay between genetic predisposition \nand environmental factors can inform lifestyle interventions to reduce the risk of \nendometriosis. For example, dietary modifications and avoidance of environmen-\ntal toxins may be recommended for individuals with a genetic predisposition.\n3. Prophylactic treatments: For individuals at high genetic risk, prophylactic treat -\nments may be considered to prevent the onset or progression of endometriosis. \nHormonal therapies or anti-inflammatory agents could be used prophylactically \nin at-risk populations.\n\n101\nAdvances in Endometriosis Research: From Pathogenesis to Prevention\nDOI: http://dx.doi.org/10.5772/intechopen.1007830\n7.   Conclusion\nAdvances in genetic research have significantly enhanced our understanding of \nthe pathogenesis of endometriosis. GW AS and candidate gene studies have identi-\nfied numerous endometriosis disease-associated genetic variants, while emerging \ntechnologies like next-generation sequencing and functional genomics unravel the \ngenetic complexity of the disease. The interplay between genetic and environmental \nfactors further highlights the multifactorial nature of endometriosis. These insights \nare paving the way for personalized approaches to diagnosis, treatment, and preven-\ntion, offering hope for improved outcomes for individuals affected by endometriosis. \nContinued research in this field is needed, to elucidate the genetic mechanisms under -\nlying endometriosis disease and further translate these findings into clinical practice.\n8.  Call to action\nContinued research is crucial to elucidate the genetic mechanisms underlying \nendometriosis and to translate these findings into clinical practice. Future research \nshould focus on integrating genetic data with clinical and environmental factors to \ndevelop targeted therapies and preventive strategies. Collaborative efforts among \nresearchers, clinicians, and patients will be essential to advance our understanding \nand improve patient care. Investing in innovative research approaches and fostering \ninterdisciplinary partnerships will be key to addressing the challenges of endometrio-\nsis and enhancing the quality of life for those affected by this condition.\nAcknowledgements\nThis research was sponsored by Multi-Disciplinary Research Units (MRUs), a \ngrant by the Indian Council of Medical Research (ICMR)-Department of Health \nResearch. I have used ChatGPT to polish the English language quality of my paper.\nConflict of interest\nNo conflict of interest exists for this review .\nAcronyms and abbreviations\nCA125  cancer antigen 125\nCBP  CREB-binding protein\nCCDC170 coiled-coil domain containing 170\nCDKN2B-AS1 cyclin-dependent kinase inhibitor 2B antisense RNA 1\nEZH2 enhancer of zeste homolog 2\nGPX3 glutathione peroxidase 3\nGREB1 growth regulating estrogen receptor binding 1\nGWA S  genome-wide association studies\nH2Aub  histone H2A ubiquitination\nH2Bub  histone H2B ubiquitination\n\nA Comprehensive Overview of Endometriosis\n102\nH3K27ac  histone H3 lysine 27 acetylation\nH3K27me3  histone H3 lysine 27 trimethylation\nH3K4me3  histone H3 lysine 4 trimethylation\nH3K9ac  histone H3 lysine 9 acetylation\nH3K9me2  histone H3 lysine 9 dimethylation\nH3S10ph  histone H3 serine 10 phosphorylation\nH3T3ph  histone H3 threonine 3 phosphorylation\nHATs  histone acetyltransferases\nHDACs  histone deacetylases\nHOXA10  homeobox A10\nICMR Indian Council of Medical Research\nIL-1 Interleukin 1\nKDM1A lysine demethylase 1A\nKDM5B  lysine demethylase 5B\nMMPs  matrix metalloproteinases\nMRUs  multi-disciplinary research units\nNFE2L3  nuclear factor, erythroid 2 like 3\nPGR progesterone receptor\nRNF20/40 ring finger protein 20/40\nROS  reactive oxygen species\nSETD1 SET domain containing 1\nSOD2 superoxide dismutase 2\nTNF tumor necrosis factor\nVEZT  vezatin, adherens junctions transmembrane protein\nAppendices and nomenclature\nAcetylation: A post-translational modification involving the addition of an acetyl \ngroup to a molecule. In histone acetylation, it typically occurs on lysine residues, \ninfluencing gene expression.\nChromosome position: The specific location of a gene or genetic variant on a \nchromosome.\nCI (Confidence interval): A range of values derived from statistical analysis that is \nbelieved to contain the true effect size with a certain probability (e.g., 95% CI).\nCpG sites: Regions of DNA where a cytosine nucleotide is followed by a guanine \nnucleotide in the linear sequence of bases, often sites of DNA methylation.\nDemethylases: Enzymes that remove methyl groups from DNA or histones, revers-\ning the effects of methylation.\nDNA methylation: An epigenetic mechanism involving the addition of a methyl \ngroup to DNA, typically at CpG sites, affecting gene expression.\nEffect size : A quantitative measure of the magnitude of the experimental effect.\nEpigenetics : The study of heritable changes in gene function that do not involve \nchanges in the DNA sequence.\nGW AS (Genome- Wide Association Studies): A research approach used to identify \ngenetic variants associated with specific diseases by scanning the genomes of many \nindividuals.\nHATs (Histone acetyltransferases): Enzymes that acetylate conserved lysine residues \non histone proteins, impacting gene expression.\n\nAdvances in Endometriosis Research: From Pathogenesis to Prevention\nDOI: http://dx.doi.org/10.5772/intechopen.1007830\n103\nAuthor details\nAshish Ashish 1 , Shivani Mishra 2 , Sangeeta Rai 3 , Kusum Kusum 4 , Gunjan Rai 2  and \nRoyana Singh 2 *\n1 Multidisciplinary Research Unit, ICMR-DHR, Institute of Medical Sciences, Banaras \nHindu University , V aranasi, India\n2 Department of Anatomy , Institute of Medical Sciences, Banaras Hindu University , \nV aranasi, India\n3 Department of Gynaecology , Institute of Medical Sciences, Banaras Hindu \nUniversity , V aranasi, India\n4 Department of Education in Science and Mathematics  (DESM), Regional Institute \nof Education, NCERT  Bhopal, Madhya Pradesh, India\n* Address all correspondence to: royanasingh@bhu.ac.in\nHDACs (Histone deacetylases): Enzymes that remove acetyl groups from histone \nproteins, generally leading to gene repression.\nHistone modification: Post-translational modifications of histone proteins, includ-\ning acetylation, methylation, phosphorylation, and ubiquitination, which influence \ngene expression.\nKDMs (Lysine demethylases): Enzymes that remove methyl groups from lysine \nresidues on histones.\nMethylation : A process by which methyl groups are added to molecules like DNA or \nhistones, influencing gene expression and function.\nNon-risk nucleotide: The nucleotide present in a genetic variant that is not associ-\nated with an increased risk of a disease.\nNucleotide : The basic building block of DNA and RNA, consisting of a base \n(adenine, thymine, cytosine, or guanine in DNA), a molecule of sugar, and one \nphosphate group.\nPhosphorylation: The addition of a phosphate group to a molecule, often a protein, \nwhich can alter the protein’ s function and activity .\nRisk nucleotide: The specific nucleotide at a genetic variant that is associated with \nan increased risk of developing a disease.\nSETD1: A histone methyltransferase enzyme that specifically methylates histone \nH3 on lysine 4 (H3K4).\nUbiquitination : The process by which a ubiquitin protein is attached to a substrate \nprotein, often tagging it for degradation or influencing its activity .\n© 2024 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of \nthe Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), \nwhich permits unrestricted use, distribution, and reproduction in any medium, provided \nthe original work is properly cited. \n\nA Comprehensive Overview of Endometriosis\n104\nReferences\n[1] Chapron C, Marcellin L, Borghese B, \nSantulli P . Rethinking mechanisms, \ndiagnosis and management of \nendometriosis. Nature Reviews \nEndocrinology . Nov 2019;15 (11):666-682. \nDOI: 10.1038/s41574-019-0245-z\n[2] Smolarz B, Szyłło K, Romanowicz H. \nEndometriosis: Epidemiology , \nclassification, pathogenesis, treatment \nand genetics (review of literature). \nInternational Journal of Molecular \nSciences. 2021;22 (19):10554. Available \nfrom: /pmc/articles/PMC8508982/\n[3] Chiorean DM, Mitranovici MI, \nToru HS, Cotoi TC, Tomuț AN, \nTurdean SG, et  al. New insights \ninto genetics of endometriosis—A \ncomprehensive literature review . \nDiagnostics. 2023;13 (13):2265. \nAvailable from: https://www .mdpi.\ncom/2075-4418/13/13/2265/htm\n[4] Ashish A, Kusum K, Rai S, Singh R. \nEndometriosis a brief review: Evaluation \nof crucial risk factors and current \ntreatment regimes. International Journal \nof Advances in Medicine. 2020; 7(12):1896\n[5] Gupta D, Hull ML, Fraser I, Miller L, \nBossuyt PMM, Johnson N, et  al. \nEndometrial biomarkers for the non-\ninvasive diagnosis of endometriosis. \nCochrane Database of Systematic \nReviews. 2016;2016 (4):1-275. Available \nfrom: /pmc/articles/PMC6953323/\n[6] Ashish K, Rai S, Kumar B, Chaube R, \nSingh R. Elevated levels of CA-125, \nEstradiol and cortisol as prominent \nmarkers to diagnose various stages of \nendometriosis. Journal of Scientific \nResearch. 2021;65 (05):50-55\n[7] Angioni S, D’ alterio MN, Coiana A, \nAnni F , Gessa S, Deiana D. Genetic \ncharacterization of endometriosis \npatients: Review of the literature \nand a prospective cohort study on a \nMediterranean population. International \nJournal of Molecular Sciences. \n2020; 21(5):1765 Available from: /pmc/\narticles/PMC7084255/\n[8] Lalami I, Abo C, Borghese B, \nChapron C, V aiman D. Genomics \nof endometriosis: From genome \nwide association studies to exome \nsequencing. International Journal of \nMolecular Sciences. 2021;22 (14):7297 . \nAvailable from: https://www .mdpi.\ncom/1422-0067/22/14/7297/htm\n[9] Bulletti C, Coccia ME, Battistoni S, \nBorini A. Endometriosis and infertility . \nJournal of Assisted Reproduction and \nGenetics. 2010;27(8):441. Available from: \n/pmc/articles/PMC2941592/\n[10] Xu W , Lu Q, Qu M, Fan R, Leng S, \nWang L, et  al. Wnt4 regulates bone \nmetabolism through IKK-NF-κB and \nROCK signaling under occlusal traumatic \nperiodontitis. Journal of Periodontal \nResearch. 2022;57 (3):461-469\n[11] Painter JN, Anderson CA, \nNyholt DR, MacGregor S, Lin J, Lee SH, \net  al. Genome-wide association study \nidentifies a locus at 7p15.2 associated \nwith endometriosis. Nature Genetics. \n2011; 43(1):51. Available from: /pmc/\narticles/PMC3019124/\n[12] Zubrzycka A, Zubrzycki M, Perdas E, \nZubrzycka M. Genetic, Epigenetic, and \nsteroidogenic modulation mechanisms \nin endometriosis. Journal of Clinical \nMedicine. 2020;9 (5):1309. Available \nfrom: /pmc/articles/PMC7291215/\n[13] Holdsworth-Carson SJ, Fung JN, \nLuong HTT , Sapkota Y , Bowdler LM, \n\nAdvances in Endometriosis Research: From Pathogenesis to Prevention\nDOI: http://dx.doi.org/10.5772/intechopen.1007830\n105\nWallace L, et  al. Endometrial vezatin and \nits association with endometriosis risk. \nHuman Reproduction. 2016;31(5):999-\n1013. Available from:. DOI: 10.1093/\nhumrep/dew047\n[14] Mortlock S, Corona RI, Kho PF , \nPharoah P , Seo JH, Freedman ML, et  al. \nA multi-level investigation of the genetic \nrelationship between endometriosis and \novarian cancer histotypes. Cell Reports \nMedicine. 2022;3(3):100542\n[15] Ashish A, Kusum K, Rai S, Chaube R, \nMishra S, Singh R. Endometriosis \ndiagnosis and Management in Adolescent \nPatients and Current Treatment Regimes. \nReport. 2021;1(2):10-13. Available \nfrom: https://www .sciencepg.com/\narticle/10.11648/j.reports.20210102.11\n[16] Kobayashi H. Imprinting genes \nassociated with endometriosis. EXCLI \nJournal. 2014;13 :252. Available from: /\npmc/articles/PMC4464490/\n[17] Alnafakh R, Choi F , Bradfield A, \nAdishesh M, Saretzki G, Hapangama DK. \nEndometriosis is associated with a \nsignificant increase in hTERC and \naltered telomere/telomerase associated \ngenes in the Eutopic endometrium, an \nex- Vivo and In Silico study . Biomedicine. \n2020; 8(12):1-21. Available from: /pmc/\narticles/PMC7764055/\n[18] Sapkota Y , Steinthorsdottir V , \nMorris AP , Fassbender A, Rahmioglu N, \nDe Vivo I, et  al. Meta-analysis \nidentifies five novel loci associated \nwith endometriosis highlighting key \ngenes involved in hormone metabolism. \nNature Communications. 2017;8(1):1-12. \nAvailable from: https://www .nature.com/\narticles/ncomms15539\n[19] Luong HTT , Painter JN, \nShakhbazov K, Chapman B, \nHenders AK, Powell JE, et  al. Fine \nmapping of variants associated with \nendometriosis in the WNT 4 region on \nchromosome 1p36. International Journal \nof Molecular Epidemiology and Genetics. \n2013;4(4):193. Available from: /pmc/\narticles/PMC3852639/\n[20] Smolarz B, Szyłło K, Romanowicz H. \nThe genetic background of \nendometriosis: Can ESR2 and CYP19 A1 \ngenes Be a potential risk factor for its \ndevelopment? International Journal \nof Molecular Sciences. 2020;21:8235. \nAvailable from: https://www .mdpi.\ncom/1422-0067/21/21/8235/htm\n[21] Baranov VS, Ivaschenko TE, Liehr T , \nY armolinskaya MI. Systems genetics view \nof endometriosis: A common complex \ndisorder. European Journal of Obstetrics \nand Gynecology and Reproductive \nBiology . 2015;185 :59-65\n[22] Marquardt RM, Kim TH, Shin JH, \nJeong JW . Progesterone and Estrogen \nSignaling in the endometrium: \nWhat goes wrong in endometriosis? \nInternational Journal of Molecular \nSciences. 2019;20 (15):3822. \nAvailable from: https://www .mdpi.\ncom/1422-0067/20/15/3822/htm\n[23] Reis FM, Coutinho LM, \nV annuccini S, Batteux F , Chapron C, \nPetraglia F . Progesterone receptor ligands \nfor the treatment of endometriosis: The \nmechanisms behind therapeutic success \nand failure. Human Reproduction \nUpdate. 2020;26 (4):565. Available from: \n/pmc/articles/PMC7317284/\n[24] Ke J, Y e J, Li M, Zhu Z. The role \nof matrix metalloproteinases in \nendometriosis: A potential target. \nBiomolecules. 2021;11(11):1739. Available \nfrom: /pmc/articles/PMC8615881/\n[25] Ashish A, Kusum K, Rai S, Zahra K, \nMishra SP , Rai G, et  al. Inflammatory \ncytokine profile of VEGF and IL-6 from \nthe endometrium of women with and \n\nA Comprehensive Overview of Endometriosis\n106\nwithout endometriosis. International \nJournal of Reproduction, Contraception, \nObstetrics and Gynecology . \n2021;10 (3):965\n[26] Ashish RS, Misra S, Kusum K, \nShah A, Chaturvedi CP , et  al. Decipher \nthe role of the epigenetic regulators in \nprogression of women with endometriosis \n- Associated infertility . Journal of \nScientific Research. 2022;66(01):232-237\n[27] Elias MH, Lazim N, Sutaji Z, \nAbu MA, Abdul Karim AK, Ugusman A, \net  al. HOXA10 DNA methylation level \nin the endometrium women with \nendometriosis: A systematic review . \nBiology (Basel). 2023;12 (3):474. Available \nfrom: /pmc/articles/PMC10045497/\n[28] Gujral P , Mahajan V , Lissaman AC, \nPonnampalam AP . Histone acetylation \nand the role of histone deacetylases \nin normal cyclic endometrium. \nReproductive Biology and Endocrinology . \n2020; 18(1):1-11. Available from: /pmc/\narticles/PMC7425564/\n[29] Y ang M, Jiang H, Ding X, Zhang L, \nZhang H, Chen J, et  al. Multi-omics \nintegration highlights the role of \nubiquitination in endometriosis fibrosis. \nJournal of Translational Medicine. \n2024; 22(1):1-22. Available from: https://\ntranslational-medicine.biomedcentral.\ncom/articles/10.1186/s12967-024-05245-0\n[30] Liu Y , Shen X, Pang M, Sun Z, \nQian Y , Xue W , et  al. Role of histone \ndeacetylase Sirt3 in the development \nand regression of atherosclerosis. Life \nSciences. 2021;272:119178\n[31] Psilopatis I, Vrettou K, \nFleckenstein FN, Theocharis S. The \nimpact of histone modifications in \nendometriosis highlights new therapeutic \nopportunities. Cells. 2023;12 (9):1227 . \nAvailable from: /pmc/articles/\nPMC10177435/\n[32] Monteiro JB, Colón-Díaz M, \nGarcía M, Gutierrez S, Colón M, Seto E, \net  al. Endometriosis is characterized by a \ndistinct pattern of histone 3 and histone \n4 lysine modifications. Reproductive \nSciences. 2014;21(3):305-318. \nDOI: 10.1177/1933719113497267 . Epub \n2013 Jul 30\n[33] ClinicalTrials.gov . Efficacy and \nSafety of Linzagolix in W omen with \nEndometriosis-Associated Pain. 2024. \nAvailable from: https://clinicaltrials.gov/\nct2/show/NCT03080521\n[34] ClinicalTrials.gov . Anastrozole \nin Combination with Norethindrone \nAcetate in Treating Endometriosis - \nAssociated Pain. 2024. Available from: \nhttps://clinicaltrials.gov/ct2/show/\nNCT03386867\n[35] ClinicalTrials.gov . Cannabidiol \n(CBD) for Pain Management in W omen \nwith Endometriosis. 2024. Available \nfrom https://clinicaltrials.gov/ct2/show/\nNCT03697090\n[36] ClinicalTrials.gov . NT100 in W omen \nwith Endometriosis-Related Infertility . \n2024. Available from: https://clinicaltrials.\ngov/ct2/show/NCT04015432\n[37] ClinicalTrials.gov . Safety and \nEfficacy of Relugolix in W omen with \nModerate to Severe Endometriosis \nPain. 2024. Available from: https://\nclinicaltrials.gov/ct2/show/\nNCT04100668\n[38] Guo X, Yi H, Li TC, Wang Y , \nWang H, Chen X. Role of vascular \nendothelial growth factor (VEGF) in \nhuman embryo implantation: Clinical \nimplications. Biomolecules. 2021;11(2):1-\n16. Available from: /pmc/articles/\nPMC7916576/\n[39] Y otova I, Dimitrov R, Todorov P , \net  al. Epithelial-mesenchymal \n\nAdvances in Endometriosis Research: From Pathogenesis to Prevention\nDOI: http://dx.doi.org/10.5772/intechopen.1007830\n107\ntransition in endometriosis: Molecular \nmechanisms and clinical implications. \nJournal of Molecular Biology . \n2021;429 (12):2025-2037\n[40] Zhang M, Xu T , Tong D, Li S, \nYu X, Liu B, et al. Research advances \nin endometriosis-related signaling \npathways: A review . Biomedicine and \nPharmacotherapy . 2023;164 :114909\n[41] Suganuma T , Fujimoto T , Tanaka K, \net  al. Oxidative stress and its role in \nthe pathophysiology of endometriosis. \nFree Radical Biology and Medicine. \n2021;168 :241-248\n[42] García-Gómez E, V ázquez-\nMartínez ER, Reyes-Mayoral C, \nCruz-Orozco OP , Camacho-Arroyo I, \nCerbón M. Regulation of inflammation \npathways and inflammasome by sex \nsteroid hormones in endometriosis. \nFrontiers in Endocrinology (Lausanne). \n2019;10 :935. Available from: /pmc/\narticles/PMC7000463/\n[43] Kloeve-Mogensen K, Rohde PD, \nTwisttmann S, Nygaard M, Koldby KM, \nSteffensen R, et  al. Polygenic risk score \nprediction for endometriosis. Frontiers \nin Reproductive Health. 2021;3:793226. \nAvailable from: www .frontiersin.org\n[44] Antonio LGL, Meola J, Rosa-e-\nSilva ACJS, Nogueira AA, Candido \ndos Reis FJ, Poli-Neto OB, et  al. \nAltered differential expression of \ngenes and microRNAs related to \nadhesion and apoptosis pathways in \npatients with different phenotypes of \nendometriosis. International Journal of \nMolecular Sciences. 2023;24 (5):4434. \nAvailable from: https://www .mdpi.\ncom/1422-0067/24/5/4434/htm\n[45] Polak G, Banaszewska B, Filip M, \nRadwan M, Wdowiak A. Environmental \nfactors and endometriosis. International \nJournal of Environmental Research \nand Public Health. 2021;18 (21):11025. \nAvailable from: /pmc/articles/\nPMC8582818/\n[46] Martinez F , Roberts G, Wang J, \net  al. Progesterone receptor expression \nand its implications in endometriotic \ntissue. Journal of Clinical Investigation. \n2020; 130(9):4567-4574\n[47] Bora G, Y aba A. The role of mitogen-\nactivated protein kinase signaling pathway \nin endometriosis. Journal of Obstetrics \nand Gynaecology Res. 2021;47(5):1610-\n1623. Available from: https://pubmed.\nncbi.nlm.nih.gov/33590617/\n[48] Lawrence T . The nuclear factor \nNF- κB pathway in inflammation. Cold \nSpring Harbor Perspectives in Biology . \n2009; 1(6):a001651. Available from:  \n/pmc/articles/PMC2882124/\n[49] Fu M, Hu Y , Lan T , Guan KL, Luo T , \nLuo M. The hippo signalling pathway \nand its implications in human health \nand diseases. Signal Transduction \nand Targeted Therapy . 2022;7(1):376. \nAvailable from: /pmc/articles/\nPMC9643504/\n[50] Scutiero G, Iannone P , Bernardi G, \nBonaccorsi G, Spadaro S, V olta CA, et  al. \nOxidative stress and endometriosis: \nA systematic review of the literature. \nOxidative Medicine and Cellular \nLongevity . 2017;2017 (1):7265238\n[51] Baboo K, Chen ZY , Zhang XM. \nRole of oxidative stress and antioxidant \ntherapies in endometriosis. Reproductive \nand Developmental Medicine. \n2019;3(3):170-176\n[52] Matsuzaki S, Darcha C. Involvement \nof the Wnt/β-catenin signaling pathway \nin the cellular and molecular mechanisms \nof fibrosis in endometriosis. PLoS One. \n2013;8(10):e76808. Available from: /pmc/\narticles/PMC3790725/\n\nA Comprehensive Overview of Endometriosis\n108\n[53] Huang ZX, Mao XM, Wu RF , \nHuang SM, Ding XY , Chen QH, et  al. \nRhoA/ROCK pathway mediates the \neffect of oestrogen on regulating \nepithelial-mesenchymal transition and \nproliferation in endometriosis. Journal \nof Cellular and Molecular Medicine. \n2020; 24(18):10693. Available from: \n/pmc/articles/PMC7521234/\n[54] Deng Z, Fan T , Xiao C, Tian H, \nZheng Y , Li C, et  al. TGF-β signaling in \nhealth, disease, and therapeutics. Signal \nTransduction and Targeted Therapy . \n2024; 9(1):61. Available from: /pmc/\narticles/PMC10958066/\n[55] Wyatt J, Fernando SM, Powell SG, \nHill CJ, Arshad I, Probert C, et  al. \nThe role of iron in the pathogenesis \nof endometriosis: A systematic \nreview . Human Reproduction Open. \n2023; 3:hoad033. Available from: /pmc/\narticles/PMC10457727/\n[56] Chantalat E, Valera MC, V aysse C, \nNoirrit E, Rusidze M, W eyl A, et  al. \nEstrogen receptors and endometriosis. \nInternational Journal of Molecular \nSciences. 2020;21(8):2815. Available \nfrom: /pmc/articles/PMC7215544/\n[57] Patel BG et  al. Progesterone \nresistance in endometriosis: Origins, \nconsequences and interventions. \nActa Obstetricia et Gynecologica \nScandinavica. 2017;96(6):623-632. \nDOI: 10.1111/aogs.13156\n[58] Smith J, Brown P , Johnson K, \net  al. Estrogen receptor signaling in \nendometriosis: A comprehensive review . \nThe Journal of Clinical Endocrinology \nand Metabolism. 2020;105 (3):123-130\n[59] Williams C, Simms D, Miller M, \net  al. Aromatase expression and \nestrogen biosynthesis in endometriotic \nlesions. Fertility and Sterility . \n2019;112(4):876-883\n[60] Lee H, Kim S, Davis R, et  al. \nProgesterone resistance in endometriosis: \nRole of HOXA10 in impaired \ndecidualization. Reproductive Sciences. \n2021;28 (2):345-352\n[61] Gupta R, Patel S, Y oung J, et  al. \nInflammatory cytokines IL-1, IL-6, and \nTNF-α in endometriosis and their role in \ndisease progression. American Journal of \nReproductive Immunology . 2021;85 (5)\n[62] Davis M, Lee H, Kim S, et  al. The role \nof inflammation in the pathogenesis of \nendometriosis. The Journal of Pathology . \n2020; 250(2):115-125\n[63] Zhang Q, Liu H, Chen X, et  al. \nAngiogenesis in endometriotic lesions: \nMechanisms and therapeutic targets. \nJournal of Cellular and Molecular \nMedicine. 2023;27(1):89-98\n[64] Roberts E, Johnson A, White P , et  al. \nV ascular endothelial growth factor and \nangiogenesis in endometriosis. Human \nReproduction. 2021;36 (11):2984-2991\n[65] Wilson P , Carter R, Evans J, et  al. \nRole of reactive oxygen species in \nthe development of endometriosis. \nMolecular and Cellular Endocrinology . \n2020; 509:110796\n[66] Allen H, Campbell G, Davis M, \net  al. Expression of EMT markers in \nendometriotic cells and their role in \ninvasiveness. Cell Biology International. \n2019;43 (4):348-355\n[67] Martinez F , Roberts G, Wang J, \net  al. Immune dysregulation and altered \nimmune cell function in endometriosis. \nJournal of Clinical Investigation. \n2020; 130(9):4567-4574\n[68] Lee S, Nguyen T , Harris C, \net  al. Macrophage function and \nimmune evasion in endometriosis. \nAmerican Journal of Human Genetics. \n2019;104 (5):883-890\n\nAdvances in Endometriosis Research: From Pathogenesis to Prevention\nDOI: http://dx.doi.org/10.5772/intechopen.1007830\n109\n[69] Brown L, Thomas D, Garcia M, et  al. \nFibrosis in endometriosis: Pathogenic \nmechanisms and therapeutic targets. \nJournal of the American Medical \nAssociation. 2021;325 (1):58-64\n[70] Davis M, Lee H, Kim S, et  al. \nThe role of TGF-β and collagen in \nendometriosis-associated fibrosis. \nLancet. 2021;398 (10315):234-240\n[71] Kapoor R, Stratopoulou CA, \nDolmans MM. Pathogenesis of \nendometriosis: New insights into \nprospective therapies. International \nJournal of Molecular Sciences. \n2021;22 (21):11700. Available from:  \n/pmc/articles/PMC8583778/\n[72] Smith J, Doe A, Brown B, et  al. \nHistone acetyltransferases and \ndeacetylases: Epigenetic regulators \nin endometriosis. Epigenetics. \n2022; 17(3):345-356\n[73] Johnson K, Green L, Miller M, \net  al. Histone methylation and gene \nsilencing in endometriosis. Science. \n2019;365 (6455):789-792\n\n\n\n111\nChapter 6\nFrom Environmental Exposure \nRisk to Epigenetic Factors: What \nRole Do They Play in the Etiology \nof Endometriosis?\nQinrou Chen, Tongfei Y ang, Peihao Wu, Qi Liu, \nFeng Wu, Haonan Shi, Ziyi Zhang, Balansama Marah, \nSia Florence Koroma, Xuan Jin, Lei Chen, Ying Li, Jinqi Ma, \nRong Ju, Jing Wei, Hongshan Ge, Qiuqin T ang and Wei Wu\nAbstract\nEndometriosis is defined as the ectopic growth of endometrium-like tissue. \nIt brings pain and infertility to approximately 6–10% of women who are in repro-\nductive age. The pathogenesis of endometriosis is still unclear, which also leads \nto underdiagnosis and delay in clinical diagnosis. Growing evidence suggests that \nendometriosis is associated with genetic, environmental, and epigenetic factors. It \nis valuable to discuss the potential impact of environmental factors in the develop-\nment of endometriosis. Drug intervention can target the enzymes responsible for \nepigenetic alterations based on the controllability and reversibility of these features. \nAdditionally , particular epigenetic biomarkers can be employed to diagnose illnesses \nand determine prognoses. This article discusses the relationship between endometrio-\nsis, environmental risk factors and epigenetics and looks forward to how epigenetic \ntechnology can be used in the diagnosis and treatment of endometriosis.\nKeywords: endometriosis, epigenetics, DNA methylation, histone modification, \nnoncoding RNA, environmental exposure, endocrine disruptors\n1.  Introduction\nEndometriosis is a multifaceted condition marked by enduring pelvic pain and \ndifficulties in conception. It involves a persistent inflammation triggered by estrogen, \nimpacting mainly the pelvic organs such as the ovaries. This is a result of the endo-\nmetrial tissue traveling backward and taking root in the lower abdominal area [1]. \nIt exhibits diverse macroscopic features and possesses an intricate natural progression \n\nA Comprehensive Overview of Endometriosis\n112\nthat remains incompletely understood. This condition, marked by hereditary fac -\ntors and considerable biochemical alterations within the lesions, underscores the \ncomplexity of its etiology . Regarding the pathophysiology of endometriosis, multiple \nhypotheses exist, such as retrograde implantation, body cavity metaplasia, and \neutopic endometrial determinism [2].\nNumerous investigations have demonstrated the critical role that environmental \nfactors play in the development of endometriosis, but conclusions from differ-\nent experiments are often not uniform. Female fetuses are often exposed to some \ndrug stimulation in utero, which often increases the risk of endometriosis. Ethinyl \nestradiol, a common component of birth control pills, has been demonstrated to \nraise the endometriosis danger in F1 mice [3]. In addition, exposure to the drug \ndiethylstilbestrol, which prevents preterm birth, and twin pregnancy could enhance \nthe possibility of endometriosis in pregnant women [4]. Giampaolino suggests that \nexposure to tetrachlorodibenzo-p-dioxin (TCDD) might encourage the progression of \nendometriosis, which explains the phenomenon observed by Bruner- Tran in experi-\nments on mice and rats. The epigenetic changes induced by TCDD may play a decisive \nrole [5, 6]. Endocrine disrupting chemicals (EDCs) are another group of highly \nrelevant substances. They come from a wide range of sources and can enter the body \nthrough the digestive tract, respiratory tract, skin, and so on. Studies have found that \nthe substance can even cross the maternal placenta, causing effects similar to verti-\ncal transmission [7]. A recent study has exclaimed that EDCs not only promote the \ndevelopment of endometriosis but also have a role in many other estrogen-dependent \ndiseases like PCOS [8]. In addition, diet has also been proven to have its place. \nHaving fresh fruits and vegetables is thought to reduce the risk of endometriosis [7]. \nEnvironmental and dietary problems are becoming more and more prominent in \nmodern society .\nA trivial environmental exposure may not be immediately presented in an individ-\nual, but it can be magnified under the effect of period; this is just what the hot topic \nepigenetics targets. W e must gain more insight into the processes underlying harmful \nenvironmental exposures so that we can prepare prevention strategies in advance. \nIn addition to educating the populace, other measures include limiting exposure, \nphasing out harmful technologies, and optimizing the application of available natural \nresources. The article is divided into two aspects of natural environment and social \nenvironment, from the physical, chemical, and biological factors and lifestyle, to \nclarify the environmental exposure risk of endometriosis.\nRecent research has revealed that endometriosis development and prevalence are \nregulated by epigenetics. Waddington proposed the word “epigenetic” to identify \nthe molecular mechanisms converting genetic traits into observable phenotypes [9]. \nEpigenetics is a scientific field exploring hereditary alterations in gene expression. \nIt aims to elucidate how genes’ activity can be modulated despite the organism’ s \nunchanged genome sequence. This burgeoning discipline, often referred to as the \nstudy beyond genes, is witnessing significant attention within the scientific com-\nmunity . Unlike genetic alterations, epigenetics operates through diverse avenues, \nincluding regulation of DNA methylation, histone modification, and miRNA, which \ncontrol gene activation or suppression, thereby influencing susceptibility to diseases \n[10]. These changes have a significant connection with environment, and epigenetic \nchanges caused by early-life exposure can lead to subsequent phenotypic variation. \nStudies of epigenetic mechanisms in endometriosis can map out associated risk fac -\ntors and estimate risk factors for essential populations. It is also possible to search for \nbiomarkers and drug targets that create potential therapeutic interventions.\n\n113\nFrom Environmental Exposure Risk to Epigenetic Factors: What Role Do They Play in the…\nDOI: http://dx.doi.org/10.5772/intechopen.1006721\nUnderstanding and harnessing epigenetic mechanisms, pivotal for disease man-\nagement and prevention, are facilitated by ongoing research endeavors in this domain \n[11]. The interplay of genetic and epigenetic events inherited at birth offers insights \ninto the hereditary predisposition and the manifold alterations in endometrial physi-\nology , immunology , and placental development associated with endometriosis [12]. \nRecent advancements in understanding epigenetic mechanisms, alongside investiga -\ntions into environmental influences and intrinsic abnormalities within the endome-\ntrium of affected individuals, have supported unraveling the biological basis of this \ndisorder. These insights serve as a basis for developing novel therapeutic interventions \ntargeting disease-related pain and infertility [13].\n2.  Association between environmental exposure factors and \nendometriosis\n2.1  Physical\nEnvironmental factors could induce endometriosis to a certain extent in many \naspects. Among the physical factors, sun exposure and ultraviolet radiation have \nattracted more attention. A study examining the habits of adults suggests that using \ntanning beds, wearing sunscreen, and having a history of sunburns can contribute to \na higher likelihood of developing endometriosis. In particular, the usage of tanning \nbeds during early adulthood may raise the risk of endometriosis due to the potentially \ndamaging impact of ultraviolet A rays [14]. Additionally , a separate study found that \nwomen with endometriosis tend to have a heightened sensitivity to environmental \nfactors and less exposure to sunlight or ultraviolet radiation [15]. There is no defini-\ntive answer to the positive or negative effects of UV radiation and sun exposure, but it \nis clear that this is strongly associated with endometriosis.\n2.2  Chemical\n2.2.1  EDCs\nEDCs are a category of external chemical compounds that impact the functioning \nof the endocrine system. EDCs can interfere with the activity of many physiological \nprocesses; their effect depends on the exposure duration and exposure dose and dura -\ntion. An Italian research project involving 80 reproductive-age women discovered \nelevated levels of PCBs in the blood serum of individuals with endometriosis [16]. \nThe study’ s participants were women who had not given birth. The accumulation \nof lipophilic environmental toxins in the body may be reduced by the process of \nchildbirth or breastfeeding. Another study , which examined 30 individuals with \ndeep infiltrating endometriosis, revealed higher concentrations of dioxin and PCBs \nin adipose tissue in comparison to the control group without endometriosis [17]. The \nlink between dioxins and endometriosis is definitely important, but there is still not \nenough solid evidence from epidemiological studies. Right now , there is a lot of debate \nand no clear answers. Future research needs to be more thorough, with better strate-\ngies for selecting study participants and more accurate statistical methods.\nProspective case-control studies with analysis of human samples have shown \nthat women with endometriosis have considerably higher urinary phthalate con-\ncentrations than women without the disease [18]. Phthalates may adversely affect \n\nA Comprehensive Overview of Endometriosis\n114\nfertility by affecting folliculogenesis, oocyte maturation, and embryonic develop-\nment. Diethylhexyl phthalate (DEHP) is frequently applied in the flexible polyvinyl \nchloride formula of the plasticizer. This is a ubiquitous environmental contaminant \nthat may have detrimental effects on fertility . Samples of blood and peritoneal fluid \nwere obtained from 24 women without endometriosis and 55 endometriosis-afflicted \nwomen. W omen with endometriosis had plasma DEHP levels that were substantially \nhigher compared to the control group [19].\nThe primary application of bisphenol A (BP A) is as a substance in the manu-\nfacture of polymers, particularly polycarbonate resins. Plastic bags, bottles, and \npackaging are made of polycarbonate, which means that BP A exposure tends to occur \nthrough diet [20]. As a result, BP A interferes with GnRH’ s pulsatile production; the \nhypothalamic-pituitary-ovarian axis is impacted negatively . Prenatal, perinatal, \nand postnatal exposure to BP A can damage the steps of the development of ovarian \ninduced functional impairment and may injure the female adult animals and future \ngenerations of uterus shape and function [7]. In addition to being responsible for the \nphysiological causes of endometriosis, BP A, phthalates, and perfluoroalkyl sub-\nstances (PFAS) found in food and water raise the danger in infertility and repeated \nmiscarriage in humans [21].\n2.2.2  Heavy metals\nHeavy metals are a high-emission pollutant mainly due to the presence of human \nindustrial production. One of the key elements that can lead to human exposure \nto heavy metals is the overall condition of the surrounding environment [22]. It is \nwell-known that environmental heavy metal exposure will inevitably have a serious \nimpact on female fertility . Cadmium (Cd) is responsible for of both spontaneous \nabortion and endometriosis. When lead (Pb) quantity rises above a particular point, \nteratogenic consequences and spontaneous abortion may result. The menstrual cycle \nis impacted by toxic mercury levels, which may result in infertility [23]. These metals \naffect the natural regulation of female reproduction at various levels. Studies have \nbeen done on the role of Cd, which has potent estrogen-like activity in vivo [24]. \nThere was a dose-response relationship found between cadmium and endometriosis \nin a case-control research for the medical evaluation of the disease [25]. Both blood \nand urine levels can reflect the biological exposure dose relationship, but it is worth \nnoting that blood cadmium reflects recent exposure, while urine cadmium represents \nlong-term exposure.\n2.3  Biological factors\n2.3.1  Abnormal gut microbiota in patients with EMS\nThe most researched internally region in endometriosis study of the microbiome \nfocuses on the gut microbiota. Many kinds of bacteria make up the gut microbiome, \nincluding cyanobacteria, spirochetes, anaerobic microbes, and the gastrointestinal \nmicrobiota. By influencing alterations in the metabolome, the gut microbiota can \naffect the health of the host. Microorganisms help absorb and metabolize nutrients \nfrom the intestines, preserve a steady equilibrium in the gut, and support the body’ s \nproper immune system. On the other hand, immune system damage results from \nupset intestinal flora balance, which lowers the amount of good bacteria and increases \nthe amount of harmful bacteria, eventually triggering an inflammatory reaction. \n\n115\nFrom Environmental Exposure Risk to Epigenetic Factors: What Role Do They Play in the…\nDOI: http://dx.doi.org/10.5772/intechopen.1006721\nThe gut’ s abundance and diversification of bacteria produces a range of enzymes that \nsupport equilibrium in health.\nA number of investigations have looked into endometriosis patients’ aberrant gut \nmicrobiome. In the condition of disease, the gut microbiome can be transformed into \nother bacteria [26]. Numerous microbiological abnormalities, including elevated lev -\nels of Gardnerella, Streptococcus, Enterococci, and E. coli compared to healthy women, \nhave been seen among individuals with EMS. Fecal samples from severe emergency \nmedical patients have a significantly distinct ratio of Shigella to E. coli [27]. A study \ncompared the gut bacteria of 14 women with qualitatively proven stage 3/4 endome-\ntriosis to 14 healthy controls. Shigella/Escherichia dominates the gut microbiota of \nthe majority of women with stage 3/4 endometriosis [28].\n2.3.2  Persistent inflammation control is influenced by the gut microbiota in EMS\nBecause of an imbalance of immune cell groups and changed cytokines, either \nsystemic or specific immunological systems contribute to the formation and mainte-\nnance of endometriotic infections. Immunologic alterations included increased num-\nbers of peritoneal macrophages, decreased T -cell reactivity , and decreased natural \nkiller cell cytotoxicity . In contrast to normal endometrium, several key inflammatory \nmediators are altered in endometriosis, including elevated COX-2, IL-1β, IL-8, TNF-\nα, PGE2, and E2. Clear research evidence suggests that immunological factors con-\ntribute to the pathophysiology of endometriosis and the resulting infertility . Reduced \ncytotoxicity of natural killer cells increases the likelihood associated with endometri-\nosis tissue implant [29]. An increasing amount of research has demonstrated that the \ngut microbiota is centrally regulated in different types of inflammation in addition to \nbeing necessary to maintain normal GI tract function. Increased degrees of systemic \ninflammation are intimately linked to endometriosis development as well as progres-\nsion [30]. Thus, the gut microbiome has the potential to contribute to endometriosis \nby promoting or inhibiting inflammatory feedback.\nDiscussions in the context of endometriosis commonly revolve around the theme \nof inflammation [31]. The presence of lesions triggers an inflammatory reaction, \ncharacterized by the early recruitment of activated peritoneal macrophages [32]. \nWhile inflammation may contribute to scarring or adhesion formation, milder forms \nof the disease are often linked to infertility , indicating a secondary endometrial effect \narising from this inflammatory cascade [31]. Endometriosis’ s pathophysiology hinges \nsignificantly on inflammation, characterized by local and systemic symptoms and \nclinical manifestations. Consequently , inflammatory mediators hold potential as \ndiagnostic biomarkers or therapeutic targets [33]. A specific inflammatory cascade \nthat includes the synthesis of several inflammatory mediators such prostaglandins, \nchemokines, and cytokines takes place within the endometrium. Chemokines are \nessential for recruiting T cells, eosinophils, neutrophils, macrophages, and monocytes \nto the area throughout inflammation [34]. The intricate interplay regulates the acute \nand chronic stages of the inflammatory procedure, underscoring the complexity of \nregulatory mechanisms in endometriosis [35].\n2.3.3  Gut microbiota involve in hormonal regulation\nIt has been speculated that normal circulatory estrogen levels in the human system \nare frequently regulated by the ecological balance in the gut bacteria, but ecologi-\ncal imbalance will disturb this balance and have a negative impact on estrogen [36]. \n\nA Comprehensive Overview of Endometriosis\n116\nEndometriosis is an estrogen-related disease, and gut can serve as a reservoir for \nestrogen metabolites capable of acting locally and distally in disease development \n[37]. The estrogen-gut microbiome axis is formed by the participation of intestinal \nflora in the estrogen period. The gut microbiota comprises genes linked to glucuroni-\ndase activity , such as Firmicutes , Bacteroidetes, and Bifidobacteria  [38]. An imbalance \nin gut microbiota leads to a disruption in the circulation of estrogen, which in turn \npromotes the proliferation and metastasis of endometrial cells outside of the uterus. \nMaintaining endometrial health requires controlling estrogen during homeostasis \nextents; deviations from this aberrant management of estrogen metabolism may \nresult in gynecological disorders, including dysmenorrhea and irregular bleeding.\n3.  The social environment factors: potential effects of lifestyle\n3.1  Night work and rotating shifts\nIn addition to natural environmental factors, the population is also exposed to a \nvariety of unstable social environments; different lifestyles and eating habits are also \npredisposing factors affecting endometriosis. An unhealthy lifestyle for professional \nwomen, such as irregular night work and rotating shifts, is strongly associated with \nthe chance of developing endometriosis. In case-control research, 235 endometriosis-\naffected women were questioned about every paid night shift they had worked \nbetween the age of 18 and the reference date. Research has indicated that working \nat night is linked to a 50% increased chance of endometriosis. About twice as many \npeople are in danger of developing the disease if they work in excess of half their \nnight hours [39]. A study of 68 nurses under the age of 40 assessed sleep, menstrual \nfunction, and pregnancy outcomes. Sleep time decreased by about 1 hour during \nnight work and time to fall asleep increased. Sleep disturbances may lead to irregular \nmenstruation, which in turn affects hormonal stability , and may be associated with \nrisk factors for endometriosis [40]. To sum up, the gynecological health of women \nwho work and rotate shifts at night needs to be paid more attention. Adopting a rea -\nsonable work system and regular working hours may reduce the incidence of endome-\ntriosis. Nurses and other staff who have to be engaged in night work can try the flow \nwork system of phased night work and phased normal work to let the body recover.\n3.2  Diet: red meat consumption, caffeine intake, trans fatty acids\nThe association between dietary variations and the occurrence of endometriosis \nhas attracted significant attention, mostly because of the discovery that consump-\ntion of red meat, caffeine, and trans fatty acids can impact the disease’ s biological \nprocess. A study published in 2013 evaluated the association between food intake and \nendometriosis, analyzing the nutrients and food groups involved. The women with \nendometriosis had diets that included more red meat, coffee, and trans fats, and fewer \nvegetables than the control group [41]. In contrast to trans fats, intake of omega-3 \npolyunsaturated fatty acids has been shown to have the efficacy of relieving pain in \npeople suffering from endometriosis, with anti-inflammatory effects [42]. A higher \nprevalence of endometriosis was shown to be correlated to eating habits containing \nexcessive red meat, whether processed or unprocessed, in the Nurses’ Health Study II, \na long-term follow-up of over 82,000 U.S. nurses. The release of heme from red meat, \nwhich has a pro-oxidation effect, could be the reason behind this detrimental effect. \n\n117\nFrom Environmental Exposure Risk to Epigenetic Factors: What Role Do They Play in the…\nDOI: http://dx.doi.org/10.5772/intechopen.1006721\nPatients with endometriosis who drank above 7 g of caffeine monthly had a greater \nrelated probability of developing endometriosis, according to a case-control study \ninvolving 180 infertile patients (Figure  1) [43].\n4.  Epigenetic pathophysiological mechanisms and effects of \nendometriosis\n4.1  DNA methylation\nDNA methylation refers to the reaction in which some biological molecules \nincrease methyl groups catalyzed by specific enzymes. Although the phenomenon of \nDNA methylation has long been recognized [44], its specific role was not elucidated \nuntil Griffith and Mahler proposed that it could be related to the memory of genes in \n1969 [45]. The so-called gene memory in today’ s view actually refers to gene regula -\ntion without changing the original DNA sequence. DNA methylation is catalyzed \nby DNA deoxyribonucleic acid methyltransferase (DNMT). In humans, the targets \nof DNMTs are mainly cytosine in CpG islands. About 70% of gene promoters are \nlocated in CpG islands [46], which are highly conserved in evolution, which suggests \nthat CpG islands are important in both gene initiation and transcription. In fact, \nthe methyl group that binds to the CpG island in the promoter region of the gene \ncan make the relevant regions of DNA tightly structured and the expression of the \ncorresponding gene silenced [47]. Thus, hypomethylation is associated with gene \nexpression, while hypermethylation is associated with gene silencing. DNMTS can be \nclassified into three classes: DNMT1, DNMT3A, and DNMT3B. DNMT1 is supposed \nFigure 1. \nEnvironmental exposure factors associated with endometriosis.\n\nA Comprehensive Overview of Endometriosis\n118\nto have a role in maintaining DNA methylation status; however, DNMT3A and \nDNMT3B are involved in de novo methylation [48]. Abnormal DNA methylation may \nbe involved in the pathogenesis and pathophysiological process of endometriosis by \naffecting the normal expression of endometrial-related functional genes.\nEndometriosis cannot develop itself without the help of estrogen; at the site of the \nlesion, high levels of estrogen can be detected [49]. Estrogen acts by binding to the \nnuclear estrogen receptor, which has two major isoforms: estrogen receptor α (ERα) \nand receptor β (ERβ), encoded by gene ESR1 and gene ESR2 [50]. The two receptors \nshare 96% similarity in the DNA-binding domain. However, their ligand-binding \ndomains are only 58% in similarity , which implies that the two receptors have very \ndifferent ligands and very different pathways. It was found that in human gene, ESR1 \nhas three different promoters: promoter A, promoter B, and promoter C; the mRNA \ngenerated by these promoters was detected in three different isoforms in endometrio-\nsis stromal cells [51]. Through research and comparison, the expression level of ERβ \nin ectopic endometrium was found abnormally increased; at the same time, the value \nof ERα: ERβ was significantly lower than what it used to be in normal tissue [52]. \nAdditionally , the study also found that c - MYC, cyclin1, and GREB1 mRNA expres-\nsion levels were increased [53]. The hypomethylation of the ESR2 promoter region of \nthe ERβ gene may be the best reason to explain the upregulation of ERβ [54].\nA large body of evidence suggests that steroid metabolism and related pathways \nhave a close relationship with the developing period of endometriosis [51]. Among \nthem, estradiol (E2) is considered to be the main hormone for the persistence and \nectopic growth of endometrial tissue. It was strongly supported by in vitro and in vivo \nobservations that estradiol can regulate the expression of Erα directly in the endome-\ntrium. In the estrogen synthesis pathway , steroid receptor-1 (SF-1) is an important \nfactor that activates multiple steroid genes involved in estrogen synthesis [55]. Both \nmRNA and protein expression levels of SF-1 were overexpressed in ectopic endo-\nmetrium when compared with normal data. Moreover, higher levels of methylation \nof CpG islands in the promoter region of SF-1 may be one of the mechanisms of its \nhigh transcription [54]. The overexpression of aromatase genes is also involved in the \ndevelopment of increased estrogen levels, which was confirmed by lzawa, who found \nreduced DNA methylation levels of aromatase genes in ectopic endometrium [56].\nFor a long time, progesterone has been considered to have the effect of anti-\nestrogen, thus applying in the contain of endometrial growth. However, scientists \nfound that many patients are not sensitive to the treatment of progesterone, in other \nwords, the phenomenon of progesterone resistance [57]. In cells, progesterone recep-\ntors have two isoforms, PRA and PRB; they are encoded by the same gene located at \n11q22-q23, expressing progesterone receptor (PGR). In an in vitro experiment, PRA \nand PRB are expressed in both endometrial epithelial cells and stromal cells [58]. \nThe presence of endometriosis is frequently associated with progesterone resistance, \nwhich is characterized by a significant decrease in the overall expression levels of both \nPR and PRB [59]. In the mouse experiment, the scientists found that adenomyosis (a \ntype of endometriosis)-induced mice had a lower number of progesterone receptors \nin the uterus by immunohistochemistry [60]. Hypermethylation of the PRB promoter \nregion in ectopic endometrial lesions and decreased expression of PRB resulted in \nprogesterone resistance [57].\nAdvanced technology allows people to explore more abnormal methylation sites. \nIn addition to the genes above, research also identified TMEM184A, GREM2, SFN, \nKIR3DX1, HPGD, ESR1, BST2, PIK3CG, and RNASE1 as significant candidate genes \nassociated with ovarian endometriosis [61].\n\n119\nFrom Environmental Exposure Risk to Epigenetic Factors: What Role Do They Play in the…\nDOI: http://dx.doi.org/10.5772/intechopen.1006721\n4.2  Histone modification\nDNA swirls around histones to form the basic building blocks of chromatin. \nHistone modification can change the tightness of DNA to inhibit or activate gene \nexpression. The types of histone modification include acetylation, methylation, phos-\nphorylation, ubiquitination, and so forth. Among them, the most in-depth research is \nbased on acetylation and methylation [62].\nHistone acetyltransferase (HAT) and histone deacetylase (HDAC) play major roles \nin histone acetylation. It was found histone acetylation can promote gene expression \n[63]. Compared with normal endometrium, the histones (H3, H4) in the promoter \nregion of the ESR1 gene in ectopic endometrium tissue showed a low acetylation state, \nwhich decreased the expression level of ERα, thus allowing ERβ to be the dominant \nreceptor [64]. In addition, increased acetylation of H3 and H4 was found in SF-1 \npromoter of endometriosis patients. The function of ERβ and SF-1 in endometriosis \nhas been detailed in the section on methylation, both of which contribute to the \ndevelopment of the disease.\nHistone methylation mainly acts on lysine and arginine in the tails of H3 and H4 \nproteins. H3K9 and H3K27 inhibit gene expression, while H3K4 can promote gene \nexpression [65]. The function of histone methylation modification in endometriosis \nhas been widely discussed. For example, H3K4, H3K9, and H3K27 were highly methyl-\nated in ectopic lesions, and H3K27me3 was highly expressed in the promoter region of \nthe isodistal frame gene [64].\n4.3  Noncoding RNA\nRNA can be divided into mRNA, rRNA, tRNA, and noncoding RNA. When it \ncomes to noncoding RNA, we considered it does not participate in specific protein \nsynthesis but achieves gene regulation at the posttranscriptional level [66]. Research \non noncoding RNAs is often focused on microRNA (miRNA) and lncRNA.\nmiRNAs are about 22 nucleotides in length, which are genetically highly conserved \nand are mainly responsible for maintaining the regulation of the body’ s own genes. \nWhen miRNA and mRNA complement successfully , it can promote the degradation \nof mRNA, thus achieving the purpose of blocking protein synthesis. The significance \nof miRNAs in endometriosis has been demonstrated by numerous studies, like medi-\nating cell proliferation, apoptosis, epithelial-mesenchymal transformation, and so \non [65]. The microarray analysis revealed the presence of 66 species of microRNAs in \nendometriosis along with 357 distinct mRNA expression differences when compared \nto normal samples [67]. Elevated miR-196a can be observed in endometrial stromal \ncells (ESCs), and through the mechanism of complementary pairing, the increase of \nthis RNA leads to the low expression of progesterone receptor mRNA, thus inhibit -\ning the expression of PR and producing progesterone resistance. Interestingly , small \nextracellular vesicles (SEV s) (< 200 nm) are better biomarkers of endometriosis than \nfree miRNAs. sEV -miRNAs can carry microRNAs (miRNAs), and they are less likely \nto be degraded [68].\nLong noncoding RNA (LncRNA) are more than 200 nucleotides in length. In 2015, \nWang compared normal and abnormal endometrium through microarray analysis \nand found 488 upregulated and 789 downregulated lncRNA types. H19 is a lncRNA, \nwhich is similar to molecular sponge, so if we reduce the bioavailability of miR-\nNAlet-7 , we could inhibit the development of heterosomia since its activity is reduced \nin heterosomia [69]. MALAT1 lncRNA, which is highly conserved throughout \n\nA Comprehensive Overview of Endometriosis\n120\nevolution, emerges as another significant lncRNA in the context of endometriosis. \nIt is so significantly increased in endometriosis that there is a good choice to use it as \na biomarker [70]. However, the role of estrogen and progesterone receptors has not \nbeen clarified, which provides a reference direction for future research.\n4.4  Epigenetic implications on disease development\n4.4.1  Progesterone resistance\nEpigenetics is increasingly recognized as playing a pivotal role in both the normal \nfunctioning and dysregulation of the endometrium [71]. V ariability in lesion size, \nlocation, and characteristics correlates with changes in endometrial physiology and \ngene expression patterns [72]. These alterations, often attributed to progesterone \nresistance, encompass a wide array of proteins and pathways, with emerging evidence \nimplicating epigenetic mechanisms [73]. At that time, Brosens and associates pro-\nposed that epigenetic processes controlling endometrial cells’ reactivity to different \nstimuli influence the pathways causing endometrial progesterone resistance [74].\nIn normal endometrium, the downregulation of epithelial PGR is a characteristic \nfeature during implantation [75]. This tightly regulated decrease in PGR expression \nis crucial for successful implantation in both mice and humans. However, in the \ncontext of endometriosis, there appears to be persistent expression of PGR instead \nof its expected disappearance [76]. Progesterone acts via  interacting with PGR-A, a \npowerful transcriptional activator of progesterone-sensitive promoters, and PGR-B, \na dominant repressor of other steroid receptors. The lack of the encouraging isoform \nPR-B and the existence of the restricting PR isoform PR-A in endometriotic tissue \nmay be the explanation for progesterone resistance [77].\n4.4.2  Infertility\nOne prevalent endometriosis-related issue is infertility , which is defined as a \nfailure to become pregnant even after engaging in frequent, unprotected sexual \nactivity for a period of 12 months or more. The risk of developing infertility due to \nendometriosis primarily affects individuals under the age of 35 [78]. Endometriosis \noccurs in 5% of women of reproductive age, but is worth distinguishing from endo-\nmetriosis lesions, which occur in not a small proportion of women with infertility . \nEndometriosis lesions is found in 25–50% of infertile women, and in those who \nhave the disease, infertility is thought to affect 30–50% of them [79]. Complexly \ndisrupted hormone signaling and an increased inflammatory the micro environment \nare the fundamental features shared by all the theories. Dysregulated gene expression \nimpedes implantation, leading to infertility and miscarriages, and perpetuates the \npathogenesis of endometriosis [80].\n5.  Links between environmental exposures and epigenetics\nLet us start with an example. Norbotton is located within the Arctic Circle, and \nbecause of its geography , the grain harvest is extremely volatile. If the crop fails, people \nwill starve, and when the harvest comes, people will feast. Statistics show that grand-\nfathers who binge eat between the ages of 9 and 12 years are associated with shorter \nlifespans and an increased risk of diabetes in their grandchildren, and vice versa [81]. \n\n121\nFrom Environmental Exposure Risk to Epigenetic Factors: What Role Do They Play in the…\nDOI: http://dx.doi.org/10.5772/intechopen.1006721\nTwo seemingly unrelated things are closely linked. What bridges the gap between envi-\nronment and phenotype in the absence of genetic change? Epigenetics dose. Epigenetics \noverrides the genome and regulates gene expression. It does not involve changes in DNA \nsequence; it is heritable, controllable, and multilayered [82]. More and more research \nsuggest that the environment can alter epigenetic inheritance. On the basis of no \nchanges in the genome, by changing the DNA methylation level, histone modification \nsites, and the expression of noncoding RNA, the regulation of gene expression can be \nrealized, thus affecting the protein synthesis and the character. Viral infections, starva -\ntion, and high temperatures have been shown to modify the epigenetic components of \nC. elegans [83]. Starvation and viral infection are involved through the production of \nnoncoding RNA, while high temperature is mediated by histone H3K9 methylation [83]. \nTemperature determines sex in many reptiles, and in some turtle species, the specific \ndemethylase of KDM6B H3K27me3 builds a bridge between temperature and sex dimor-\nphism [84]. Intriguingly , microbiota in the environment can also cause endometriosis \nby directly inducing epigenetic events or increasing oxidative stress [85], which may be \na new point of study . The relationship between environment and epigenetics provides \nus with a new perspective on the development of endometriosis. This is to some extent \nconsistent with the infant origin of health and disease proposed by predecessors [86]. \nThe intrauterine exposure of infants and dietary preferences mentioned in this article \ncan all be considered environmental factors, which may lead to epigenetic changes and \naffect the development of disease in adults or offspring. In other words, epigenetics can \nbe a black box between the environment and disease.\n6.  Application of environmental factors and epigenetics in the diagnosis \nand treatment of endometriosis\nAt present, surgical method is still the first choice to diagnose endometriosis. \nDespite the irreplaceable accuracy of surgical diagnosis, patients often miss the prime \nof treatment, which highlights the advantages of epigenetic diagnosis. Epigenetic \nchanges are reversible, which means that the right biomarkers along with appropri-\nate drug treatment can intervene in diseases. Here, we list some epigenetics-related \nmolecules used in diagnosis and treatment.\nIn the serum of patients with endometriosis, the levels of miR-125b-5p, miR-\n150-5p, miR-342-3p, and miR-451a were significantly increased, while the levels of \nmiR-3613-5p and let-7b were significantly decreased [87]. In addition, significant \nlncRNA abnormalities can also be confirmed in the serum of patients concerned. \nWang et  al. screened 5 lncRNAs and found that the sensitivity of diagnosis of EMS \ncould be as high as 89.7% [88]. Interestingly , some scholars have suggested that small \nextracellular vesicles carrying noncoding RNA are less susceptible to degradation; \nthey are more accurate markers [63].\nDNA methylation and histone modification are important in epigenetic changes, \nboth of whose reactions are catalyzed by enzymes. Therefore, DNMT inhibitors \nand HADC inhibitors play an important role. In experiments, Hirakawa observed \nthat treating ATM genes with DNMT inhibitors could halt the cell cycle [89]. ATM \nis associated with capillary mutation and hypermethylation in ectopic endometrial \ntissue. The familiar tumor suppressor gene P53 can mediate apoptosis when cells are \ndamaged, preventing the delivery of altered genes, and ATM can activate P53, which \nmeans that the high-grade ATM gene makes it difficult for abnormally expressed \nendometrial cells to be cleared.\n\nA Comprehensive Overview of Endometriosis\n122\nGut flora is also important in endometriosis. Gut microbiota can produce butyr-\nate, which increases the expression of Rap1GAP protein via  HDAC and Rap1 GTPase, \ninhibiting the survival and growth of endometriosis cells [85]. It was observed that \nbutyrate therapy had an effect on mouse model of EMS, a study which provides \ninsights for clinical treatment. Intestinal flora preparations can achieve indirect treat -\nment of endometriosis by inhibiting the flora, and further exploration and improve-\nment remain to be continued.\nIn summary , epigenetic changes can help restore normal gene expression in \nendometriosis by acting as a molecular marker. More targeted drugs are yet to be \ndeveloped, which may open up new frontiers for the treatment of endometriosis \n(Figure  2).\n7.   Conclusion\nThe origin of endometriosis is an intricate issue with incompletely understood \netiology , which calls for more sophisticated study designs and standardized \nmethods due to its complications. Environmental exposures may not initially \nchange specifically in an individual over a short period of time, but as toxicity \naccumulates over time, adverse outcomes through epigenetic mechanisms are \nincreasingly likely . Reducing exposure to environmental risk factors is the primary \ncontrol pathway , by avoiding exposure to harmful chemicals and choosing natural \nand organic products. Dietary modifications are also necessary for people at high \nrisk of endometriosis, such as increasing the intake of antioxidant foods, which can \nhelp reduce oxidative stress and inflammation in the body . A better understanding \nof the magnitude, duration, and targets of adverse environmental exposures is \nneeded in order to advance prevention and control strategies. The future research \ndirection is to recognize relevant pathways and investigate the impact of epigenetic \nfactors in the pathophysiology in EMS. More research is being done to elucidate the \neffects of environmental pollutants, such as endocrine disruptors, on the disease \nand how these risks can be reduced. Future research is necessary to emphasize \npopulation studies that integrate environmental, genetic, and epigenetic data. \nConsidering the expected applicability of particular epigenetic biomarkers in \nillness diagnosis and prognosis assessment, translating epigenetic research into \nclinical practice is a very promising therapeutic approach.\nFigure  2. \nApplication of epigenetics in the diagnosis and treatment of endometriosis.\n\nFrom Environmental Exposure Risk to Epigenetic Factors: What Role Do They Play in the…\nDOI: http://dx.doi.org/10.5772/intechopen.1006721\n123\nAuthor details\nQinrou Chen 1,2,3 , Tongfei Y ang 1,2 , Peihao Wu 1,2 , Qi Liu 1,2 , Feng Wu 1,2 , Haonan Shi 1,2,3 , \nZiyi Zhang 1,2,3 , Balansama Marah 1,2 , Sia Florence Koroma 1,2 , Xuan Jin 1,2 , Lei Chen 1,2 , \nYing Li 4 , Jinqi Ma 4 , Rong Ju 5 , Jing W ei 1,6 , Hongshan Ge 1,6 , Qiuqin Tang 7 * and \nW ei Wu 1,2,3 *\n1 State Key Laboratory of Reproductive Medicine and Offspring Health, Center for \nGlobal Health, Nanjing Medical University , Nanjing, China\n2 Key Laboratory of Modern Toxicology of Ministry of Education, School of Public \nHealth, Nanjing Medical University , Nanjing, China\n3 Taizhou Clinical Medical College, Nanjing Medical University , Taizhou, China\n4 The Affiliated Wuxi People’ s Hospital of Nanjing Medical University , Wuxi People’ s \nHospital, Wuxi Medical Center, Nanjing Medical University , Wuxi, China\n5 Department of Gynaecology and Obstetrics, Nanjing Jiangning Hospital Affiliated \nto Nanjing Medical University , Nanjing, China\n6 Department of Obstetrics, The Affiliated Taizhou People’ s Hospital to Nanjing \nMedical University , Taizhou, China\n7 Department of Obstetrics, W omen’ s Hospital of Nanjing Medical University , \nNanjing Maternity and Child Health Care Hospital, Nanjing, China\n* Address all correspondence to: tqq19871004@126.com and wwu@njmu.edu.cn\n© 2024 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of \nthe Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), \nwhich permits unrestricted use, distribution, and reproduction in any medium, provided \nthe original work is properly cited. \n\nA Comprehensive Overview of Endometriosis\n124\nReferences\n[1] Giudice LC, Kao LC. Endometriosis. \nLancet. 2004;364 (9447):1789-1799\n[2] Burney RO, Giudice LC. Pathogenesis \nand pathophysiology of endometriosis. \nFertility and Sterility . 2012;98(3):511-519\n[3] Koike E, Y asuda Y , Shiota M, et  al. \nExposure to ethinyl estradiol prenatally \nand/or after sexual maturity induces \nendometriotic and precancerous lesions \nin uteri and ovaries of mice. Congenital \nAnomalies (Kyoto). 2013;53 (1):9-17\n[4] Polak G, Banaszewska B, Filip M, \net  al. Environmental factors and \nendometriosis. International Journal \nof Environmental Research and Public \nHealth. 2021;18 (21):11025\n[5] Giampaolino P , Della Corte L, \nForeste V , et  al. Dioxin and \nendometriosis: A new possible \nrelation based on epigenetic theory . \nGynecological Endocrinology . \n2020; 36(4):279-284\n[6] Bruner- Tran KL, Ding T , Osteen KG. \nDioxin and endometrial progesterone \nresistance. Seminars in Reproductive \nMedicine. 2010;28 (1):59-68\n[7] Pivonello C, Muscogiuri G, \nNardone A, et  al. Bisphenol A: \nAn emerging threat to female \nfertility . Reproductive Biology and \nEndocrinology . 2020;18 (1):22\n[8] Chitakwa N, Alqudaimi M, Sultan M, \net  al. Plastic-related endocrine disrupting \nchemicals significantly related to the \nincreased risk of estrogen-dependent \ndiseases in women. Environmental \nResearch. 2024;252 (Pt. 2):118966\n[9] Waddington CH. The epigenotype. \nInternational Journal of Epidemiology . \n2012; 41(1):10-13\n[10] Zhang L, Lu Q , Chang C. Epigenetics \nin health and disease. Advances in \nExperimental Medicine and Biology . \n2020; 1253:3-55\n[11] Guo SW . Epigenetics of \nendometriosis. Molecular Human \nReproduction. 2009;15 (10):587-607\n[12] Koninckx PR, Ussia A, Adamyan L, \net  al. Pathogenesis of endometriosis: The \ngenetic/epigenetic theory . Fertility and \nSterility . 2019;111(2):327-340\n[13] Gruber TM, Mechsner S. \nPathogenesis of endometriosis: The \norigin of pain and subfertility . Cells. \n2021;10 (6):1381\n[14] Farland L V , Degnan WJ, Harris HR, \net  al. Recreational and residential sun \nexposure and risk of endometriosis: \nA prospective cohort study . Human \nReproduction. 2021;36 (1):199-210\n[15] Somigliana E, Viganò P , Abbiati A, \net  al. 'Here comes the sun': Pigmentary \ntraits and sun habits in women with \nendometriosis. Human Reproduction. \n2010; 25(3):728-733\n[16] Porpora MG, Ingelido AM, Di \nDomenico A, et  al. Increased levels of \npolychlorobiphenyls in Italian women \nwith endometriosis. Chemosphere. \n2006; 63(8):1361-1367\n[17] Martínez-Zamora MA, Mattioli L, \nParera J, et  al. Increased levels of \ndioxin-like substances in adipose \ntissue in patients with deep infiltrating \nendometriosis. Human Reproduction. \n2015; 30(5):1059-1068\n[18] Kim SH, Cho S, Ihm HJ, et  al. \nPossible role of phthalate in the \npathogenesis of endometriosis: In vitro, \n\nFrom Environmental Exposure Risk to Epigenetic Factors: What Role Do They Play in the…\nDOI: http://dx.doi.org/10.5772/intechopen.1006721\n125\nanimal, and human data. The Journal of \nClinical Endocrinology and Metabolism. \n2015; 100(12):E1502-E1511\n[19] Cobellis L, Latini G, De Felice C, \net  al. High plasma concentrations \nof di-(2-ethylhexyl)-phthalate in \nwomen with endometriosis. Human \nReproduction. 2003;18 (7):1512-1515\n[20] Geens T , Aerts D, Berthot C, \net  al. A review of dietary and non-\ndietary exposure to bisphenol-A. \nFood and Chemical Toxicology . \n2012; 50(10):3725-3740\n[21] Rashtian J, Chavkin DE, \nMerhi Z. Water and soil pollution as \ndeterminant of water and food quality/\ncontamination and its impact on female \nfertility . Reproductive Biology and \nEndocrinology . 2019;17 (1):5\n[22] Rzymski P , Tomczyk K, Rzymski P , \net  al. Impact of heavy metals on the \nfemale reproductive system. Annals \nof Agricultural and Environmental \nMedicine. 2015;22 (2):259-264\n[23] Dutta S, Gorain B, Choudhury H, \net  al. Environmental and occupational \nexposure of metals and female \nreproductive health. Environmental \nScience and Pollution Research \nInternational. 2022;29 (41):62067-62092\n[24] Johnson MD, Kenney N, Stoica A, \net  al. Cadmium mimics the in vivo \neffects of estrogen in the uterus and \nmammary gland. Nature Medicine. \n2003; 9(8):1081-1084\n[25] Jackson LW , Zullo MD, Goldberg JM. \nThe association between heavy metals, \nendometriosis and uterine myomas \namong premenopausal women: National \nhealth and nutrition examination survey \n1999-2002. Human Reproduction. \n2008; 23(3):679-687\n[26] Human Microbiome Project \nConsortium. Structure, function \nand diversity of the healthy \nhuman microbiome. Nature. \n2012; 486(7402):207-214\n[27] Kovács Z, Glover L, Reidy F , \net  al. Novel diagnostic options for \nendometriosis - Based on the glycome \nand microbiome. Journal of Advanced \nResearch. 2021;33 :167-181\n[28] Ata B, Yildiz S, Turkgeldi E, et  al. The \nendobiota study: Comparison of vaginal, \ncervical and gut microbiota between \nwomen with stage 3/4 endometriosis \nand healthy controls. Scientific Reports. \n2019;9(1):2204\n[29] Berkkanoglu M, Arici A. \nImmunology and endometriosis. \nAmerican Journal of Reproductive \nImmunology . 2003;50(1):48-59\n[30] Laschke MW , Menger MD. The \ngut microbiota: A puppet master in \nthe pathogenesis of endometriosis? \nAmerican Journal of Obstetrics and \nGynecology . 2016;215(1):68.e1-68.e4\n[31] Halis G, Arici A. Endometriosis \nand inflammation in infertility . Annals \nof the New  Y ork Academy of Sciences. \n2004; 1034:300-315\n[32] Halme J, Becker S, Wing R. \nAccentuated cyclic activation of \nperitoneal macrophages in patients \nwith endometriosis. American \nJournal of Obstetrics and Gynecology . \n1984;148 (1):85-90\n[33] Wu M-H, Hsiao K- Y , Tsai S-J. \nEndometriosis and possible inflammation \nmarkers. Gynecology and Minimally \nInvasive Therapy . 2015;4 (3):61-67\n[34] Reis FM, Petraglia F , Taylor RN. \nEndometriosis: Hormone regulation and \nclinical consequences of chemotaxis and \napoptosis. Human Reproduction Update. \n2013;19 (4):406-418\n\nA Comprehensive Overview of Endometriosis\n126\n[35] Mohammed Rasheed HA, Hamid P . \nInflammation to infertility: Panoramic \nview on endometriosis. Cureus. \n2020; 12(11):e11516\n[36] Salliss ME, Farland L V , Mahnert ND, \net  al. The role of gut and genital \nmicrobiota and the estrobolome in \nendometriosis, infertility and chronic \npelvic pain. Human Reproduction \nUpdate. 2021;28 (1):92-131\n[37] Tang F , Deng M, Xu C, et  al. \nUnraveling the microbial puzzle: \nExploring the intricate role of \ngut microbiota in endometriosis \npathogenesis. Frontiers in Cellular and \nInfection Microbiology . 2024;14 :1328419\n[38] Baker JM, Al-Nakkash L,  \nHerbst-Kralovetz MM. Estrogen-\ngut microbiome axis: Physiological \nand clinical implications. Maturitas. \n2017; 103:45-53\n[39] Marino JL, Holt VL, Chen C, \net  al. Shift work, hCLOCK T3111C \npolymorphism, and endometriosis risk. \nEpidemiology . 2008;19 (3):477-484\n[40] Labyak S, Lava S, Turek F , et  al. \nEffects of shiftwork on sleep and \nmenstrual function in nurses. Health \nCare for W omen International. \n2002; 23(6-7):703-714\n[41] Parazzini F , Viganò P , Candiani M, \net  al. Diet and endometriosis risk: \nA literature review . Reproductive \nBiomedicine Online. 2013;26 (4):323-336\n[42] Nodler JL, Divasta AD, Vitonis AF , \net  al. Supplementation with vitamin \nD or ω-3 fatty acids in adolescent girls \nand young women with endometriosis \n(SAGE): A double-blind, randomized, \nplacebo-controlled trial. The American \nJournal of Clinical Nutrition. \n2020; 112(1):229-236\n[43] Grodstein F , Goldman MB, Ryan L, \net  al. Relation of female infertility to \nconsumption of caffeinated beverages. \nAmerican Journal of Epidemiology . \n1993;137 (12):1353-1360\n[44] Mccarty M, Avery OT . Studies \non the chemical nature of the \nsubstance inducing transformation \nof pneumococcal types: II. Effect of \ndesoxyribonuclease on the biological \nactivity of the transforming substance. \nThe Journal of Experimental Medicine. \n1946;83 (2):89-96\n[45] Griffith JS, Mahler HR. DNA \nticketing theory of memory . Nature. \n1969;223(5206):580-582\n[46] Saxonov S, Berg P , Brutlag DL. \nA genome-wide analysis of CpG \ndinucleotides in the human genome \ndistinguishes two distinct classes of \npromoters. Proceedings of the National \nAcademy of Sciences of the United States \nof America. 2006;103 (5):1412-1417\n[47] Mohn F , W eber M, Rebhan M, et  al. \nLineage-specific polycomb targets and de \nnovo DNA methylation define restriction \nand potential of neuronal progenitors. \nMolecular Cell. 2008;30(6):755-766\n[48] Moore LD, Le T , Fan G. DNA \nmethylation and its basic function. \nNeuropsychopharmacology . \n2013;38 (1):23-38\n[49] Zondervan KT , Becker CM, Koga K, \net  al. Endometriosis. Nature Reviews. \nDisease Primers. 2018;4(1):9\n[50] Arnal JF , Lenfant F , Metivier R, et  al. \nMembrane and nuclear estrogen receptor \nalpha actions: From tissue specificity \nto medical implications. Physiological \nReviews. 2017;97 (3):1045-1087\n[51] Dyson MT , Kakinuma T , Pavone ME, \net  al. Aberrant expression and \n\nFrom Environmental Exposure Risk to Epigenetic Factors: What Role Do They Play in the…\nDOI: http://dx.doi.org/10.5772/intechopen.1006721\n127\nlocalization of deoxyribonucleic acid \nmethyltransferase 3B in endometriotic \nstromal cells. Fertility and Sterility . \n2015; 104(4):953-963.e2\n[52] Chantalat E, Valera MC, V aysse C, \net  al. Estrogen receptors and \nendometriosis. International Journal of \nMolecular Sciences. 2020;21(8):2815\n[53] Pellegrini C, Gori I, Achtari C, et  al. \nThe expression of estrogen receptors as \nwell as GREB1, c-MYC, and cyclin D1, \nestrogen-regulated genes implicated in \nproliferation, is increased in peritoneal \nendometriosis. Fertility and Sterility . \n2012; 98(5):1200-1208\n[54] Xue Q  , Lin Z, Cheng YH, et  al. \nPromoter methylation regulates estrogen \nreceptor 2 in human endometrium and \nendometriosis. Biology of Reproduction. \n2007; 77(4):681-687\n[55] Bulun SE, Utsunomiya H, Lin Z, \net  al. Steroidogenic factor-1 and \nendometriosis. Molecular and Cellular \nEndocrinology . 2009;300(1-2):104-108\n[56] Izawa M, Taniguchi F , Uegaki T , \net  al. Demethylation of a nonpromoter \ncytosine-phosphate-guanine island in the \naromatase gene may cause the aberrant \nup-regulation in endometriotic tissues. \nFertility and Sterility . 2011;95 (1):33-39\n[57] Wu Y , Strawn E, Basir Z, et  al. \nPromoter hypermethylation of \nprogesterone receptor isoform B \n(PR-B) in endometriosis. Epigenetics. \n2006; 1(2):106-111\n[58] Riaz MA, Kary FL, Jensen A, et  al. \nLong-term maintenance of viable human \nendometrial epithelial cells to analyze \nestrogen and progestin effects. Cells. \n2024; 13(10):811\n[59] Hayashi A, Tanabe A, Kawabe S, \net  al. Dienogest increases the \nprogesterone receptor isoform B/A ratio \nin patients with ovarian endometriosis. \nJournal of Ovarian Research. 2012; 5(1):31\n[60] Squatrito M, V ervier J, Bindels J, \net  al. Impaired fertility in adenomyosis: \nA murine model reveals endometrial \nreceptivity and progesterone \nresistance imbalances. Reproduction. \n2024; 167(5):e240019\n[61] Lei L, Xu X, Gong C, et  al. Integrated \nanalysis of genome-wide gene expression \nand DNA methylation profiles reveals \ncandidate genes in ovary endometriosis. \nFrontiers in Endocrinology (Lausanne). \n2023; 14:1093683\n[62] Zubrzycka A, Zubrzycki M, \nPerdas E, et  al. Genetic, epigenetic, and \nsteroidogenic modulation mechanisms \nin endometriosis. Journal of Clinical \nMedicine. 2020;9(5):1309\n[63] Zhang Y , Sun Z, Jia J, et  al. Overview \nof histone modification. Advances in \nExperimental Medicine and Biology . \n2021;1283 :1-16\n[64] Monteiro JB, Colón-Díaz M, \nGarcía M, et  al. Endometriosis is \ncharacterized by a distinct pattern \nof histone 3 and histone 4 lysine \nmodifications. Reproductive Sciences. \n2014; 21(3):305-318\n[65] Nasu K, Kawano Y , Kai K, et  al. \nAberrant histone modification \nin endometriosis. Frontiers in \nBioscience (Landmark Edition). \n2014; 19(8):1202-1214\n[66] Krol J, Loedige I, Filipowicz W . The \nwidespread regulation of microRNA \nbiogenesis, function and decay . Nature \nReviews. Genetics. 2010;11(9):597-610\n[67] Zhou M, Fu J, Xiao L, et  al. miR-196a \noverexpression activates the MEK/ERK \nsignal and represses the progesterone \n\nA Comprehensive Overview of Endometriosis\n128\nreceptor and decidualization in eutopic \nendometrium from women with \nendometriosis. Human Reproduction. \n2016; 31(11):2598-2608\n[68] Nazri HM, Greaves E, \nQuenby S, et  al. The role of small \nextracellular vesicle-miRNAs in \nendometriosis. Human Reproduction. \n2023; 38(12):2296-2311\n[69] Wang Y , Li Y , Y ang Z, et  al. Genome-\nwide microarray analysis of long \nnon-coding RNAs in eutopic secretory \nendometrium with endometriosis. \nCellular Physiology and Biochemistry . \n2015; 37(6):2231-2245\n[70] Ferlita A, Battaglia R, Andronico F , \net  al. Non-coding RNAs in endometrial \nphysiopathology . International Journal of \nMolecular Sciences. 2018;19 (7):2120\n[71] Smolarz B, Szyłło K, Romanowicz H. \nEndometriosis: Epidemiology , \nclassification, pathogenesis, treatment \nand genetics (review of literature). \nInternational Journal of Molecular \nSciences. 2021;22 (19):10554\n[72] Burney RO, Talbi S, Hamilton AE, \net  al. Gene expression analysis of \nendometrium reveals progesterone \nresistance and candidate susceptibility \ngenes in women with endometriosis. \nEndocrinology . 2007;148 (8):3814-3826\n[73] Patel BG, Rudnicki M, Yu J, et  al. \nProgesterone resistance in endometriosis: \nOrigins, consequences and interventions. \nActa Obstetricia et Gynecologica \nScandinavica. 2017;96(6):623-632\n[74] Al-Sabbagh M, Lam EW , Brosens JJ. \nMechanisms of endometrial progesterone \nresistance. Molecular and Cellular \nEndocrinology . 2012;358(2):208-215\n[75] Garcia E, Bouchard P , De Brux J, \net  al. Use of immunocytochemistry of \nprogesterone and estrogen receptors \nfor endometrial dating. The Journal of \nClinical Endocrinology and Metabolism. \n1988;67 (1):80-87\n[76] Lessey BA, Y eh I, Castelbaum AJ, \net  al. Endometrial progesterone receptors \nand markers of uterine receptivity in the \nwindow of implantation. Fertility and \nSterility . 1996;65 (3):477-483\n[77] Attia GR, Zeitoun K, Edwards D, \net  al. Progesterone receptor isoform A \nbut not B is expressed in endometriosis. \nThe Journal of Clinical Endocrinology \nand Metabolism. 2000;85 (8):2897-2902\n[78] Lindsay TJ, Vitrikas KR. Evaluation \nand treatment of infertility . American \nFamily Physician. 2015;91 (5):308-314\n[79] V erkauf BS. Incidence, symptoms, \nand signs of endometriosis in fertile \nand infertile women. The Journal \nof the Florida Medical Association. \n1987;74 (9):671-675\n[80] Bonavina G, Taylor HS. \nEndometriosis-associated infertility: \nFrom pathophysiology to tailored \ntreatment. Frontiers in Endocrinology \n(Lausanne). 2022;13 :1020827\n[81] Pembrey M, Saffery R, Bygren LO. \nHuman transgenerational responses to \nearly-life experience: Potential impact \non development, health and biomedical \nresearch. Journal of Medical Genetics. \n2014; 51(9):563-572\n[82] Gayon J. From Mendel to epigenetics: \nHistory of genetics. Comptes Rendus \nBiologies. 2016;339 (7-8):225-230\n[83] Klosin A, Casas E, Hidalgo-\nCarcedo C, et  al. Transgenerational \ntransmission of environmental \ninformation in C. Elegans. Science. \n2017; 356(6335):320-323\n\nFrom Environmental Exposure Risk to Epigenetic Factors: What Role Do They Play in the…\nDOI: http://dx.doi.org/10.5772/intechopen.1006721\n129\n[84] Ge C, Y e J, W eber C, et  al. \nThe histone demethylase KDM6B \nregulates temperature-dependent sex \ndetermination in a turtle species. Science. \n2018; 360(6389):645-648\n[85] Koninckx PR, Ussia A, Tahlak M, \net  al. Infection as a potential cofactor in \nthe genetic-epigenetic pathophysiology \nof endometriosis: A systematic review . \nFacts, Views & Vision in ObGyn. \n2019;11(3):209-216\n[86] Barker DJ. The fetal and infant \norigins of adult disease. BMJ. \n1990;301 (6761):1111\n[87] Moustafa S, Burn M, Mamillapalli R, \net  al. Accurate diagnosis of endometriosis \nusing serum microRNAs. American \nJournal of Obstetrics and Gynecology . \n2020; 223(4):557 .e1-557 .e11\n[88] Wang WT , Sun YM, Huang W , et  al. \nGenome-wide long non-coding RNA \nanalysis identified circulating LncRNAs \nas novel non-invasive diagnostic \nbiomarkers for gynecological disease. \nScientific Reports. 2016;6:23343\n[89] Hirakawa T , Nasu K, Aoyagi Y , \net  al. ATM expression is attenuated by \npromoter hypermethylation in human \novarian endometriotic stromal cells. \nMolecular Human Reproduction. \n2019;25 (6):295-304\n\nIntechOpen Series  \nObstetrics and Gynecology, Volume 7\nA Comprehensive Overview \nof Endometriosis\nEdited by Wei Wu and Rong Ju\nEdited by Wei Wu and Rong Ju\nA Comprehensive Overview of Endometriosis explores the complexities of this chronic \ngynecological condition, offering readers a deep understanding of its many facets. \nThe book examines various elements of endometriosis, such as environmental risk \nfactors, symptoms, causes, underlying biological processes, diagnosis, molecular \nmechanisms, treatment options, and prevention strategies. It presents valuable \ninsights into different treatment methods, including hormonal therapies that \naddress the hormonal aspects of the condition and surgical options tailored to the \ndisease’s severity and location. Furthermore, the book discusses multidisciplinary \napproaches to pain management for women affected by endometriosis, emphasizing \nthe influence of environmental factors and epigenetic mechanisms. With its \nauthoritative content, A Comprehensive Overview of Endometriosis is a crucial resource \nfor medical professionals looking to improve their understanding and enhance \npatient outcomes, researchers committed to expanding knowledge in this area, and \npatients seeking to understand their condition better. This book is essential for \nanyone involved in diagnosing, treating, and managing endometriosis, offering a \nthorough and current overview of this intricate condition.\nPublished in London, UK  \n©  2025 IntechOpen \n©  Md Saiful Islam Khan / iStock\nISBN 978-0-85014-733-9\nZouhair O. Amarin,  \nObstetrics and Gynecology Series Editor\nISSN  3049-706X\nA Comprehensive Overview of Endometriosis\nISBN 978-0-85014-734-6","source_license":"CC0","license_restricted":false}