Background
Endometriosis is a proliferative disease that is defined as the
presence of endometrial glands and stroma outside the uterine
cavity; or in extrauterine sites, it is a common chronic gynecological
disease; the incidence in women of reproductive age is 5 to 17%; its
cause is unknown; But, the accepted hypothesis is the implantation
of endometrial tissue in the peritoneal cavity due to retrograde
menstruation, or when endometrial tissues and cells adhere to the
surfaces of the peritoneum, annexes and other pelvic organs [1-4].
The main symptoms are dysmenorrhea, pelvic pain and infertility.
Although endometriosis is considered a benign condition, it shares
some characteristics of cancer proliferation, such as invasion, tissue
damage, neoangiogenesis and spread to distant organs [3].
The development of cancer is a rare complication of
endometriosis, and mainly in some gynecological cancers 5 and
others extragonadal [3], the first case of malignant transformation
was described in 1925 1 of endometriosis in the intestinal tract, 17
cases have been reported of neoplastic changes 6; the most common
location being the colon and rectum-sigmoid (50 to 90%) 1 small
intestine (7%), blind (3.6%) and appendix (3%); other locations
are in the pleura, pericardium, navel, rectovaginal septum (13%) 7,
bladder, lungs, central nervous system and even skin 1, as in scars
from surgeries or previous episiotomies, [5-8], (Figure 1). Despite
epidemiological evidence, the association between endometriosis
and cancer has not been elucidated so far.
Figure 1: The female pelvis in (a) ventral and (b) lateral views,
which indicate the sites of endometriosis.
Endometriosis is hormonally dependent on estrogens, it is
associated with oxidative stress, inflammatory pathways that are
activated in its microenvironment [7,8]; but, molecular events
involved in malignant transformation are under investigation,
and early molecular alterations have been identified such as the
alteration of a tumor suppressor gene, the mutation of the ARID1A
Abstract
Endometriosis is a common benign disease in women of reproductive age, it has been associated with an increased risk of various malignancies
that is defined by certain histological criteria mainly 80% in ovary and 20% in extragonadal sites such as intestine, rectovaginal septum, abdominal
wall , pleura and others; the greatest risk for colorectal cancer is women with adenomyosis or endometriosis; Several genetic alterations have
been found in the risk of endometriosis associated with cancer; The symptomatology, imaging and endoscopic characteristics simulate other
inflammatory and malignant lesions that make the preoperative diagnosis of extragonadal endometriosis difficult. This is a review of the knowledge
about endometriosis and its potential risk of malignancy, particularly with colorectal cancer.
Keywords
Endometriosis; Colorectal cancer; Neoplasms associated with endometriosis; Adenomyosis; Malignant transformation; Simulation
World Journal of Gynecology & Women’s Health Volume 3-Issue 2
Citation: Victor Manuel Vargas Hernandez, José María Tovar Rodríguez, Víctor Manuel Vargas Aguilar. Endometriosis as a Risk Factor for
Colorectal Cancer. W J Gynecol Women’s Health. 3(2): 2020. WJGWH.MS.ID.000560. DOI: 10.33552/WJGWH.2020.03.000560.
Page 2 of 5
and loss of its encoded BAF250a [5]. The association between
endometriosis and other hormone-dependent cancers particularly
endometrial cancer (EC) and breast cancer (CM), share common
risk factors (FR), such as hyperestrogenism, some reproductive
characteristics, obesity, the administration of menopausal
hormone therapy (THM) and Type 2 diabetes mellitus (DM2)
[8-10]; When clinical-pathological characteristics are compared
between primary CE and synchronous epithelial ovarian cancer
(EOC) [10], the incidence of endometriosis is higher in patients
with EC than in EOC (100% vs. 35%), other malignant neoplasms
such as colorectal cancer which is one of the most frequent intra-
abdominal cancers in women that could exist in association with
endometriosis. Uterine adenomyosis or internal endometriosis is
when the ectopic endometrial glands and stroma are impregnated
to the myometrium that can also be associated with an increased
risk of cancer [3,9,10].
The clinical presentation of intestinal endometriosis is usually
asymptomatic, or with gastrointestinal bleeding, nausea, vomiting,
abdominal pain, defecation pain; diarrhea, constipation, rectum-
vaginal colonic mass, intussusception, intestinal obstructions and
intestinal perforation are observed; Symptomatology worsens
during menstruation by 40%: Imaging and endoscopy of the
intestinal tract simulates other inflammatory and malignant lesions;
the definitive diagnosis before surgery is difficult, only clinical
suspicion can prevent it [2]; consider patients with endometriosis,
especially postmenopausal patients with a recurrence of symptoms
[11,12 ] (Table 1).
Table 1: General characteristics of endometriosis.
Sites % Symptomatology Differential Diagnosis or MRI
Bladder 6.4-20 Dysuria, hematuria, urinary retention
Symptoms, suprapubic pain
Uranus remnant, epithelial and mesenchymal
tumors
Ureters 0.01–1 Dysmenorrhea, dyspareunia, flank
pain (hydronephrosis) CC obstruction
Ovaries 20–40 Nonspecific pelvic pain Teratomas or hemorrhagic ovarian cysts,
endometrioid cancers or clear ovarian cells
Round ligaments 0.3–14 Painful inguinal mass, nonspecific pelvic pain cysts, endometrioid cancers
Retro cervical region
Uterosacral ligaments 6-9.2 Painful symptoms, dyspareunia clear ovarian cells.
Vagina 14.5 dysmenorrhea, dyspareunia, postcoital
Rectosigmoid colon Dysquecia, Cyclic pain,
rectorrhagia Dysquecia, cyclic pain, rectorrhagia Colorectal cancer, metastatic implants
RM (Magnetic Resonance imaging)
CC (Cervical Cancer)
Endometriosis and Cancer Risk
Women with endometriosis are at risk of developing cancer
of 87.2 per 10,000 patients / year, or risk ratio of (OR) 1.8 with
a 95% CI of 1.4 to 2.4; the time to develop endometriosis cancer
was 34.3 months (18.7–46.8 months) and that is when they have
adenomyosis; and increases with age, with OR 2.3 for those aged
31 to 40, 2.9; for 41 to 50 years and 4.2 for those 50 years of age or
older [10,11,13].
Imaging and Pathology Studies of Intestinal
Endometriosis
Figure 2: Image of computed tomography (CT) with contrast
showing eccentric thickening of the wall of the rectum-sigmoid
junction.
The diagnostic suspicion of intestinal endometriosis is
mainly clinical, based on symptomatology; however, the lack of
pathological signs makes diagnosis difficult; even during surgery
intestinal endometriosis is confused with neoplasms, despite the
use of computed tomography (CT) tomography [1,14], Figure 2 or
magnetic resonance imaging (MRI), lto detection of wall nodules
within the attached masses, when the atypical characteristics in the
MRI sequences suggest a possible malignant Figure 3. It is generally
diagnosed by histological findings after surgical resection [12]
(Figures 4-6).
Figure 3: Magnetic resonance imaging (MRI) (a) Sagittal, (b)
axial oblique and (c) coronal oblique T2 weighted at T2 show
speculated hypointense areas arranged at confluent angles (white
arrows) with loss of cleavage planes between the anterior surface
of the sigmoid, the posterior serosa of the uterus and bilateral
endometriomas (white arrowheads).
Citation: Victor Manuel Vargas Hernandez, José María Tovar Rodríguez, Víctor Manuel Vargas Aguilar. Endometriosis as a Risk Factor for
Colorectal Cancer. W J Gynecol Women’s Health. 3(2): 2020. WJGWH.MS.ID.000560. DOI: 10.33552/WJGWH.2020.03.000560.
World Journal of Gynecology & Women’s Health Volume 3-Issue 2
Page 3 of 5
Figure 4: Macroscopic appearance of endometriotic nodule of
sigmoid colon. The arrows indicate the intact mucous layer.
Figure 5: Adenocarcinoma that infiltrates the colon. Tumor cells
form irregular glands.
Figure 6: Small focus of endometriosis near the tumor in the
muscles of the colon.
Pathological and immunohistochemical staining (IHQ) is
essential to make a diagnosis, IHQ stains, which include CK 7,
CK 20, vimentin and estrogen receptors (RE) [6], are useful to
distinguish between adenocarcinoma arising from endometriosis
and adenocarcinoma Primary intestinal [1,6]. The endometrioid
glands are usually immunoreactive for CK7, RE, and stromal cells
are positive for CD10 and RE. The intestinal glands express CDX2
and CK20, while showing a negative expression of CK7, RE or CD10.
PAX8 was shown to be expressed in gynecological cancers [1].
Discussion
Endometriosis is defined histologically as the presence of
endometrial glands and stroma outside the uterine cavity; common
benign disease in women of reproductive age, the frequency of
intestinal endometriosis varies from 3 to 34% 16; it affects the
intestinal tract in 15 to 37% of patients with pelvic endometriosis
[13]. Many theories about its pathogenesis have been proposed, the
most accepted proposes retrograde menstruation and subsequent
implantation of endometrial cells implanted in the peritoneum
and pelvic viscera, which is facilitated by immune alterations; It
is located in various anatomical sites, peritoneum, ovary, fallopian
tubes, cervix, vagina, vulva, rectovaginal septum, uterus-sacral
ligaments, intestine, rectosigmoid, bladder, uterus and skin [13].
Cancer develops in 5.5% of patients with endometriosis; 21.3%
of cases originate in extragonadal pelvic sites, intestinal tumors
associated with endometriosis are even more rare; in patients
with pelvic endometriosis, it mainly affects the rectosigmoid
colon, followed by the proximal colon, small intestine, blind and
appendix. Malignant transformation of endometriosis without
pelvic involvement is rare and its actual incidence is unknown;
but, it simulates a neoplasm of the gastrointestinal tract [1,6], in a
review of endometrioid adenocarcinomas that arise in colorectal
endometriosis, of 50 cases only in 22 neoplastic transformation, it
was an adenocarcinoma.
The others included sarcomas and mixed Müllerian tumors;
progression to cancer has been linked to hyperestrogenism
and to classify cancer as a result of endometriosis, it requires
histopathological criteria; proposed by Sampson for the first time
in 1925 and are: 1) presence of malignant and benign endometrial
tissue in the same organ; 2) that the cancer arises from the tissue
and does not invade it from another place; and 3) the finding
of tissue similar to the endometrial stroma surrounding the
characteristic glands [6].
The symptoms of intestinal endometriosis include abdominal
pain, abdominal distension, signs and symptoms of gastrointestinal
obstruction, rectorrhagia, etc., depending on the segment of
the affected intestine, they can be cyclic in 40% that are usually
aggravated during menstruation. Preoperative diagnosis of
intestinal endometriosis through imaging is difficult and rare
due to other common intestinal pathologies [15]. Treatments
of intestinal endometriosis depend on presentation symptoms
and operative findings. Medical hormone therapy with surgery
provides less recurrence of endometriosis [15,16]; it is rarely
successful in severe symptomatic disease or intestinal obstruction,
surgery with intestinal resection and anastomosis is necessary,
Superficial lesions can be removed and definitive treatment
is excision is hysterectomy with bilateral salpingooporectomy
and total excision of endometrial foci by laparoscopy or by
laparotomy, with multidisciplinary team; it is associated with
improvements in the quality of life, it represents a safe approach to
the treatment of intestinal endometriosis or colorectal cancer; the
risk of subsequent colorectal cancer was elevated in patients with
coexisting adenomyosis with other extragonadal endometriosis,
OR, 13.04, not including carcinoma in situ; of cancers related to
endometriosis, colorectal is the second most common extragonadal
site for malignant transformation of endometriosis [1,2] this
World Journal of Gynecology & Women’s Health Volume 3-Issue 2
Citation: Victor Manuel Vargas Hernandez, José María Tovar Rodríguez, Víctor Manuel Vargas Aguilar. Endometriosis as a Risk Factor for
Colorectal Cancer. W J Gynecol Women’s Health. 3(2): 2020. WJGWH.MS.ID.000560. DOI: 10.33552/WJGWH.2020.03.000560.
Page 4 of 5
malignant transformation is associated with hyperestrogenism [3];
the theory of malignant endometrial transformation only explains
a small proportion of patients with colorectal cancer; In women
with coexisting adenomyosis, there are shared etiological factors
for these 2 sequential events [17]. 80% of all neoplasms associated
with extragonadal endometriosis occurred in the rectum and
sigmoid colon, mostly are adenocarcinomas. Adenocarcinoma
that arises from endometriosis often mimics primary intestinal
adenocarcinoma [1].
The possible association between endometriosis and cancer by
current molecular studies through routes related to inflammation,
oxidative stress and hyperestrogenism [3,7]and alterations
mutations of the tumor suppressor gene PTEN or ARID1A for
malignant transformation 12 and the microenvironment of
endometriosis and Associated cancer share similar cytokines and
mediators [1,2]. Epidemiological evidence supports molecular
carcinogenesis with a link between adenomyosis and gynecological
cancers, including colorectal cancer. Personalized treatment of
women with endometriosis / adenomyosis is required through
advice on early detection of cancer. There is no consensus on the
therapeutic approach to treat malignant neoplasms associated with
endometriosis, it is recommended that patients diagnosed with
carcinomas associated with extragonadal endometriosis, which
are limited to the lower pelvic cavity, can benefit from adjuvant
pelvic radiotherapy, hormone therapy, may have a similar efficacy
in malignant neoplasms associated with endometriosis with
progesterone receptors [1].
Recently a new concept has been developed in the pathogenesis
of endometriosis: the “neurological hypothesis” . showed an absolute
correlation with the anatomic distribution of the pelvic sympathetic
nervous system showed that there is a close histological relationship
between endometriotic lesions of the large intestine and nerves
in this area. Endometrioid lesions appear to infiltrate the wall of
the large intestine preferably along the nerves, even at a distance
from the palpated lesion. Endometriosis and its possible malignant
changes should be taken into account in the differential diagnosis
of intestinal masses in women. In addition, the clinical suspicion of
malignancy should be aroused in patients with abdominal pain or
rectal bleeding and a history of quiescent endometriosis [6].
Globally, cancer-associated endometriosis is very rare, and
it is really appropriate to consider it a premalignant condition;
but there is considerable controversy in the literature about the
relationship between endometriosis and cancer 6. Due to the
malignant potential, patients with endometriosis should have
adequate hormonal management even after surgery and estrogens
without opposition should generally be avoided in these patients
[8,18].
Conclusions
Endometriosis is associated with an increased risk of
cancer, including colorectal cancer mainly when coexisting with
adenomyosis. Studies on the association of adenomyosis and the
risk of colorectal cancer are needed to clarify whether the malignant
transformation of colorectal endometrial implants [19-22].
Acknowledgement
None.
Conflict of Interest
Authors declare no conflict of interest.
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