Occult appendix pathology in patients undergoing colorectal cancer resection: is there a role for incidental appendectomy?

Occult appendix pathology in patients undergoing colorectal cancer resection: is there a role for incidental appendectomy? | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Occult appendix pathology in patients undergoing colorectal cancer resection: is there a role for incidental appendectomy? Francesco Fabio, Prabhu Ravi, Niccolo Allievi, Kashuf A Khan, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-3035795/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Purpose The risk to benefit balance of incidental appendectomy in patients undergoing left colorectal cancer resection is unclear. The aim is to assess the proportion of histologically abnormal appendices in patients undergoing colorectal cancer resection in a unit where standard of care is appendectomy, with consent, when left-sided resection is performed. Methods Retrospective study on prospectively collected database, conducted in a single tertiary-care centre. Overall, 717 consecutive patients undergoing colorectal cancer resection between January 2015 and June 2021 were analysed. The primary outcome was the proportion of histologically abnormal appendix specimens at incidental appendectomy. Secondary outcome was complications from incidental appendectomy. Results Overall, 576/717(80%) patients had appendectomy at colorectal cancer surgery. In total, 234/576(41%) had a right-/extended-right hemicolectomy or sub-total colectomy which incorporates appendectomy, and 342/576(59%) had left-sided resection (left-hemicolectomy, anterior resection or abdomino-perineal excision) with incidental appendectomy. At definitive histology, 534/576(92.7%) had a normal appendix. The remaining 42/576(7.3%) showed abnormal findings, including: 14/576(2.4%) inflammatory appendix pathology, 2/576(0.3%) endometriosis, 8/576(1.4%) hyperplastic polyp, and 18/576(3.1%) appendix tumours, which encompassed 6 low-grade appendiceal mucinous neoplasms (LAMN), 3 carcinoids and 9 serrated polyps. In the 342 patients who had incidental appendectomy, 10(2.9%) had a neoplasm (2 LAMN, 3 carcinoids and 5 serrated polyps). There were no complications attributable to appendectomy. Conclusion Patients undergoing left sided colorectal cancer surgery with an appendix in situ may benefit from a co-incidental appendectomy to treat the small proportion of synchronous neoplasms and eradicate the risk of metachronous appendicitis or a subsequent appendix tumour. incidental appendectomy appendix tumour LAMN carcinoid Introduction The risk to benefit balance of removing a macroscopically normal appendix during colorectal cancer surgery is debateable. Benefits may accrue by removal of incidental pathology and avoidance of future appendicitis or malignancy, balanced against complications attributable to an appendectomy. Luminal pathology detected in a normal looking appendix include inflammatory changes, benign polyps and neoplasms. Appendix neoplasms are rare, and the age-adjusted incidence is 0.12 cases per one million people per year [ 1 , 2 ]. Approximately 50% of appendix neoplasms present as acute appendicitis [ 3 ], and the remainder found incidentally at radiological imaging, during laparotomy or laparoscopy for other abdominal pathology or detected pathologically in incidental appendectomy specimens [ 4 ]. In reports on large numbers of appendectomy specimens, the proportion of appendiceal neoplasms has been estimated to range from 0.8 to 1.4% [ 1 ]. However, appendiceal neoplasms are more frequent in patients who present with an appendix mass. Reports of interval appendicectomy after initial conservative treatment suggest that 6–12% have an underlying appendix neoplasm [ 5 , 6 ]. The aim of this study is to assess the proportion of histologically abnormal appendices in patients undergoing colorectal cancer resection in a unit where standard of care is incidental appendectomy, with consent, when left colon or rectal cancer resection is performed. Materials & Methods This is a retrospective single-centre study on a prospectively collected data base of 717 consecutive patients undergoing colorectal cancer resection between January 2015 and June 2021.The data is based on service delivery and assessment, and thus does not require formal review by the Institutional Review Board. It is standard of care in our unit to perform incidental appendectomy, with fully informed consent, when left colon or rectal cancer resection is performed based on previous publications in this field [ 7 – 10 ]. Incidental appendectomy is defined as the removal of a macroscopically normal looking vermiform appendix whilst performing another abdominal operation. Consecutive patients comprised two groups, those undergoing colorectal cancer resection with right hemicolectomy, extended-right hemicolectomy or sub-total colectomy which incorporates appendectomy, and patients undergoing left-sided resection (left-hemicolectomy, anterior resection or abdomino-perineal excision) with incidental appendectomy. Patients with known primary and metastatic appendix neoplasia were excluded. The primary tumours of the appendix include epithelial and non-epithelial tumours. An epithelial tumour can be benign (the muscularis mucosae is intact), such as tubular, tubulo-villous, villous adenoma or serrated polyp, or malignant, including low grade appendiceal mucinous neoplasm (LAMN), high-grade appendiceal mucinous neoplasm (HAMN), mucinous adenocarcinoma, signet-ring cell adenocarcinoma, and non-mucinous intestinal-type adenocarcinoma. The non-epithelial tumours include carcinoid tumours and mesenchymal tumours [ 11 , 12 ]. Demographics, American Society of Anaesthesiologists (ASA) Physical Status Classification System and the open/laparoscopic approach were reviewed. Histopathology reports were retrieved from hospital records. The proportion who had previous appendicectomy and those who had the appendix left in situ at left colon or rectal resection were recorded. All patients were discussed at the colorectal cancer multidisciplinary team meeting (MDT). When a neoplasm of the appendix was reported by the pathologist, a formal referral was made to the dedicated peritoneal malignancy MDT in case of an epithelial appendiceal neoplasm, or to the carcinoid MDT in case of a neuro-endocrine tumour, to establish a definitive management or surveillance plan. The study period of 5.5 years was considered an appropriate interval within which to achieve a meaningful number of cases to assess study outcomes. The primary outcome is the proportion of histologically abnormal appendix specimens at incidental appendectomy. Secondary outcome was specific complications from incidental appendectomy. Data were collected in an Excel spreadsheet. The analyses were performed using the statistical software STATA (College Station, Texas). Median values and interquartile range (IQR) were considered for continuous variables as their value distribution was skewed. Pearson's chi-square test was applied for analysis of categorical variables. The level of statistical significance was set at p < 0.05. Results The median age of the 717 patients included was 70 years (IQR: 62–77 years) and 422/717(59%) were male. Overall, 36(5%), 502(70%), 177(24.7%), and 2(0.3%) patients were ASA 1, 2, 3, and 4, respectively. The laparoscopic approach was used in 438/717(61%) operations. A total of 91(13%) patients had previous appendectomy. In the right-sided resection group, 37/271(14%) had previous appendectomy vs. 54/446(12%) in the left-sided resection group. In 50/446(11%) patients undergoing left sided or rectal resection the appendix was not removed due to technical difficulties or where consent had not been documented. The appendix was available for histopathological analysis in 576/717(80%) patients undergoing colorectal cancer surgery. Of these, 234/576(41%) had a right hemicolectomy, extended-right hemicolectomy or sub-total colectomy which incorporates appendectomy. The remaining 342/576(59%) had left-sided resection (left-hemicolectomy, anterior resection or abdomino-perineal excision) with incidental appendectomy. At definitive histology, 534/576(92.7%) had a normal appendix. The remaining 42/576(7.3%) showed abnormal findings, including: 14/576(2.4%) inflammatory appendix pathology, 2/576(0.3%) endometriosis, 8/576(1.4%) hyperplastic polyp, and 18/576(3.1%) appendix tumours, which encompassed 6 LAMN, 3 carcinoids and 9 serrated polyps. In the 342 patients who had incidental appendectomy, 10(2.9%) had a neoplasm (2 LAMN, 3 carcinoids and 5 serrated polyps). The definitive histology of the appendix specimen in patients having right-sided resection or sub-total colectomy vs. patients having left-sided resection and incidental appendectomy showed no substantial differences (Table 1 ). Excluding patients who had previous appendectomy, the proportion of appendixes left in place during left-sided resection was double when the laparoscopic approach was adopted, 39/247(16%) vs. 11/145(8%) in open procedures (p = 0.019). There were no complications attributable to appendectomy. Discussion The decision on whether to remove a normal looking appendix during colorectal cancer resection should be based on the likelihood of finding incidental appendix pathology and prevention of future appendix pathology balanced against the safety of the procedure. The current data demonstrates that 42/576 (7.3%) of incidental appendectomy specimens had abnormal findings at definitive histology with 18/42 (43%) having a tumour, including 6 LAMN, 3 carcinoids and 9 serrated polyps. The prevalence of appendix tumours in appendicectomy specimens has been reported in recent large series to be between 0.8%-1.4% [ 1 ]. These data are mainly based on patients who have appendectomy for appendicitis, with little data on appendix pathology at incidental appendectomy for macroscopically normal-looking appendices. In this series,1.6% of patients overall had an appendix malignant tumour, with 1.5% when considering only incidental appendectomy during left-sided colorectal resection. Similarly, 1.6% of patients had a premalignant appendix tumour (i.e.: serrated polyp), with 1.5% when considering only incidental appendectomy during left-sided colorectal resection. The rates of appendiceal pathology reported here may seem higher than observed in generic colorectal resection practice. This is undoubtedly due to a department interest in appendix tumours with dedicated pathologists prepared to analyse the appendix, even if part of a right hemicolectomy specimen. Historically, the most common primary appendiceal tumour diagnosed after appendectomy for appendicitis was carcinoid in up to 85%, with epithelial appendix neoplasms in about 20% [ 1 ]. In this report the most common tumour type was a LAMN. It is now well established that ruptured appendiceal epithelial neoplasms are the predominant cause of pseudomyxoma peritonei (PMP) [ 12 , 13 ] and removal of a non-ruptured appendiceal tumour can abolish the risk of subsequent PMP development. In a patient where a carcinoid tumour is accidentally found in the specimen, appendicectomy alone is adequate treatment for tumours < 1cm in diameter where complete resection has been achieved. For tumours measuring between 1 and 2cm in diameter, right hemicolectomy is selectively advocated, particularly with high-risk features such as mesoappendix invasion > 3mm, presence of angioinvasion, and Grade 2 histology. For tumours > 2cm in diameter, due to a greater risk of nodal involvement, right hemicolectomy is recommended [ 14 ]. Seventeen appendix specimens (2.9%) were found to contain polyps, including serrated polyps (1.5%) and hyperplastic polyps (1.4%). Serrated polyps are histologically similar to the sessile serrated lesions of the colon and rectum [ 12 ]. However, it has been shown that the molecular pathological changes are different from those found in colorectal lesions. In particular, KRAS mutations are more common and BRAF mutations less common in appendiceal serrated polyps, reflecting the fact that the serrated pathway in the appendix is probably different from that in the colon and rectum [ 15 ]. Although appendix serrated polyps are rare lesions, published series report an association of appendiceal serrated polyps with appendicitis and malignant progression [ 16 – 18 ]. Serrated polyps are pre-cancerous lesions and differentiating them from hyperplastic polyps is clinically important. Rubio et al [ 17 ] previously warned about aggressiveness of serrated polyps and Chezar at al [ 16 ] more recently published data suggesting that at least a subset of LAMNs may arise from a precursor serrated polyp. Hyperplastic polyps tend to be overall rarer in the appendix compared with the incidence in the colon and rectum [ 12 ] and are commonly benign lesions. Over 2% of patients in this series showed evidence of inflammatory changes in the appendix. It is unclear if this finding reflects a potential higher future risk of developing appendicitis, if the appendix was left in situ. Appendicitis is a common problem and approximately 40,000 people are admitted to hospital in England annually with appendicitis and it has been estimated that the lifetime risk of appendicitis is approximately 1 in 13 [ 19 ]. We propose that preventing future appendicitis in patients having major resectional cancer surgery is beneficial to avoid potential diagnostic dilemmas and significant technical difficulties should a subsequent appendicectomy be required. In patients with endometriosis, the appendix seems to be involved in 2.6% [ 20 ]. However, as our data confirm, endometriosis is quite rare in incidental appendicectomy specimens [ 21 ]. We did not encounter any complications attributable to appendectomy. There are some reasonable concerns about the risk of adding morbidity when an appendectomy is performed. This may be more of an issue at a laparoscopic procedure for left-sided colon or rectal cancer where, performing an appendectomy may be more complex due to suboptimal positioning of the ports and fatigue of the operating team. Thus, the laparoscopic approach was associated with a higher number of non-removal of the appendix. There is uncertainty regarding a possible increased risk of wound infection when an appendectomy is added during a “clean” procedure such as cholecystectomy or hysterectomy, and the literature is quite controversial [ 22 – 24 ]. However, preforming an appendectomy during a potentially contaminated operation, such as colorectal resection, is unlikely to be an additional risk of wound infection. Recently there have been reports on the effect of appendectomy in determining changes in the colonic microbiome [ 25 ]. Research in this field is ongoing and still in its infancy. Further studies are needed to clarify the short- and long-term implications of microbiome changes related to appendectomy. It is unclear what effect incidental appendicectomy would have on the specific population in the present study undergoing surgery for a colorectal cancer with a median age of 70 years. The main limitations of the study are related to the retrospective design and single-centre setting. Patients undergoing left sided colorectal cancer surgery with an appendix in situ may benefit from co-incidental appendectomy to treat the small proportion with synchronous neoplasms, polyps and inflammation and eradicate the risk of metachronous appendicitis, or a subsequent appendix tumour. Declarations Conflicts: The authors have no conflict of interest to disclose Funding: No source of funding Authors Contributions: All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Francesco Di Fabio, Prabhu Ravi, Niccolo Allievi, Kashuf Khan, and Abu Abduelraheim. The first draft of the manuscript was written by Francesco Di Fabio and Brendan Moran and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript. References Lesi O, Walton SJ, Ballanamada Appaiah NN, Rasheed N, Dahanayaka J, Ideawor P, Saad Abdalla Al-Zawi A (2021) Prevalence of Carcinoma in Appendectomy Specimens for Patients Presenting With Acute Appendicitis: A Single-Center Study. Cureus 13:e19611. O'Donnell ME, Badger SA, Beattie GC, Carson J, Garstin WI (2007) Malignant neoplasms of the appendix. Int J Colorectal Dis 22:1239-48. Connor SJ, Hanna GB, Frizelle FA (1998) Appendiceal tumors: retrospective clinicopathologic analysis of appendiceal tumors from 7970 appendectomies. Dis Colon Rectum 41:75–80. Murphy EM, Farquharson SM, Moran BJ (2006) Management of an unexpected appendiceal neoplasm. Br J Surg 93:783-92. Peltrini R, Cantoni V, Green R, Lionetti R, D'Ambra M, Bartolini C, De Luca M, Bracale U, Cuocolo A, Corcione F (2021) Risk of appendiceal neoplasm after interval appendectomy for complicated appendicitis: A systematic review and meta-analysis. Surgeon 19:e549-e558. Hayes D, Reiter S, Hagen E, Lucas G, Chu I, Muñiz T, Martinez R (2021) Is interval appendectomy really needed? A closer look at neoplasm rates in adult patients undergoing interval appendectomy after complicated appendicitis. Surg Endosc 35:3855-3860. Khan MN, Moran BJ (2007) Four percent of patients undergoing colorectal cancer surgery may have synchronous appendiceal neoplasia. Dis Colon Rectum 50:1856-9. Exner R, Sachsenmaier M, Horvath Z, Stift A (2012) Incidental appendectomy--standard or unnecessary additional trauma in surgery for colorectal cancer? A retrospective analysis of histological findings in 380 specimens. Colorectal Dis 14:1262-6. Voitk AJ, Lowry JB (1988) Is incidental appendectomy a safe practice? Can J Surg 31:448-51. Song JY, Yordan E, Rotman C (2009) Incidental appendectomy during endoscopic surgery. JSLS 13:376-83. Carr NJ, Bibeau F, Bradley RF, Dartigues P, Feakins RM, Geisinger KR, Gui X, Isaac S, Milione M, Misdraji J, Pai RK, Rodriguez-Justo M, Sobin LH, van Velthuysen MF, Yantiss RK (2017) The histopathological classification, diagnosis and differential diagnosis of mucinous appendiceal neoplasms, appendiceal adenocarcinomas and pseudomyxoma peritonei. Histopathology 71:847-858. Carr NJ (2020) Updates in Appendix Pathology: The Precarious Cutting Edge. Surg Pathol Clin 13:469-484. Ansari N, Chandrakumaran K, Dayal S, Mohamed F, Cecil TD, Moran BJ (2016) Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy in 1000 patients with perforated appendiceal epithelial tumours. Eur J Surg Oncol 42:1035-41. UK and Ireland Neuroendocrine Tumour Society guidelines. www.ukinets.org. Pai RK, Hartman DJ, Gonzalo DH, et al (2014) Serrated lesions of the appendix frequently harbor KRAS mutations and not BRAF mutations indicating a distinctly different serrated neoplastic pathway in the appendix. Hum Pathol 45:227–35. Chezar K, Minoo P (2022) Appendiceal sessile serrated lesions are distinct from their right-sided colonic counterparts and may be precursors for appendiceal mucinous neoplasms. Hum Pathol 122:40-49. Rubio CA (2004) Serrated adenomas of the appendix. J Clin Pathol 57:946-9. Martinez CA, Cutovoi J, Rossi DH, Meirelles LR, Ayrizono Mde L, Leal RF, Coy CS (2015) Intramucosal carcinoma of the appendix arising from traditional serrated adenoma. Case Rep Surg. 2015:297450. NHS UK web site. https://www.nhs.uk/conditions/appendicitis/ Mabrouk M, Raimondo D, Mastronardi M, Raimondo I, Del Forno S, Arena A, Sutherland N, Borgia A, Mattioli G, Terzano P, Seracchioli R (2020) Endometriosis of the Appendix: When to Predict and How to Manage-A Multivariate Analysis of 1935 Endometriosis Cases. J Minim Invasive Gynecol 27:100-106. Klingbeil KD, Azab B, Moller MG (2017) Low-grade appendiceal mucinous neoplasm and endometriosis of the appendix. World J Surg Oncol 15:226. Salom EM, Schey D, Peñalver M, Gómez-Marín O, Lambrou N, Almeida Z, Mendez L (2003) The safety of incidental appendectomy at the time of abdominal hysterectomy. Am J Obstet Gynecol 189:1563-7; discussion 1567-8. Huerta CT, Sundin A, Ribieras AJ, Saberi R, Ramsey W, Gilna G, Quiroz HJ, Thorson CM, Sola JE, Perez EA (2022) Nationwide outcomes of incidental appendectomy during cholecystectomy versus cholecystectomy alone in children: a propensity score-matched analysis. Pediatr Surg Int 38:1413-1420. Warren JL, Penberthy LT, Addiss DG, McBean AM (1993) Appendectomy incidental to cholecystectomy among elderly Medicare beneficiaries. Surg Gynecol Obstet 177: 288–94. Sánchez-Alcoholado L, Fernández-García JC, Gutiérrez-Repiso C at al (2020) Incidental Prophylactic Appendectomy Is Associated with a Profound Microbial Dysbiosis in the Long-Term. Microorganisms 23;8:609. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-3035795","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":208863944,"identity":"b5253629-5e57-4666-b0a9-62b8fe219e1a","order_by":0,"name":"Francesco Fabio","email":"data:image/png;base64,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","orcid":"","institution":"Colorectal Surgery, Basinsgtoke North Hampshire Hospital","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Francesco","middleName":"","lastName":"Fabio","suffix":""},{"id":208863945,"identity":"732db158-5900-46b7-b397-389334c34e77","order_by":1,"name":"Prabhu Ravi","email":"","orcid":"","institution":"Colorectal Surgery, Basinsgtoke North Hampshire Hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Prabhu","middleName":"","lastName":"Ravi","suffix":""},{"id":208863946,"identity":"003b3e59-a645-44a9-a938-a6cd87d15384","order_by":2,"name":"Niccolo Allievi","email":"","orcid":"","institution":"Colorectal Surgery, Basinsgtoke North Hampshire Hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Niccolo","middleName":"","lastName":"Allievi","suffix":""},{"id":208863947,"identity":"3c27e026-ef9a-4911-9de3-3b7aa91064d2","order_by":3,"name":"Kashuf A Khan","email":"","orcid":"","institution":"Colorectal Surgery, Basinsgtoke North Hampshire Hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Kashuf","middleName":"A","lastName":"Khan","suffix":""},{"id":208863948,"identity":"45ca11f4-02fa-4a2b-9f27-e3e2162b0bce","order_by":4,"name":"Abu Abduelraheim","email":"","orcid":"","institution":"Colorectal Surgery, Basinsgtoke North Hampshire Hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Abu","middleName":"","lastName":"Abduelraheim","suffix":""},{"id":208863949,"identity":"d62fa3aa-3206-4179-b886-10ee2edccddb","order_by":5,"name":"Brendan Moran","email":"","orcid":"","institution":"Colorectal Surgery, Basinsgtoke North Hampshire Hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Brendan","middleName":"","lastName":"Moran","suffix":""}],"badges":[],"createdAt":"2023-06-07 19:14:09","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-3035795/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-3035795/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":38623134,"identity":"2ab8d32e-8b79-4a70-b2da-55e0436a7c42","added_by":"auto","created_at":"2023-06-15 19:29:30","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":202367,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-3035795/v1/7cf2bb14-759d-4492-862b-c2119707aa03.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Occult appendix pathology in patients undergoing colorectal cancer resection: is there a role for incidental appendectomy?","fulltext":[{"header":"Introduction","content":"\u003cp\u003eThe risk to benefit balance of removing a macroscopically normal appendix during colorectal cancer surgery is debateable. Benefits may accrue by removal of incidental pathology and avoidance of future appendicitis or malignancy, balanced against complications attributable to an appendectomy.\u003c/p\u003e \u003cp\u003eLuminal pathology detected in a normal looking appendix include inflammatory changes, benign polyps and neoplasms. Appendix neoplasms are rare, and the age-adjusted incidence is 0.12 cases per one million people per year [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Approximately 50% of appendix neoplasms present as acute appendicitis [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e], and the remainder found incidentally at radiological imaging, during laparotomy or laparoscopy for other abdominal pathology or detected pathologically in incidental appendectomy specimens [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn reports on large numbers of appendectomy specimens, the proportion of appendiceal neoplasms has been estimated to range from 0.8 to 1.4% [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. However, appendiceal neoplasms are more frequent in patients who present with an appendix mass. Reports of interval appendicectomy after initial conservative treatment suggest that 6\u0026ndash;12% have an underlying appendix neoplasm [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe aim of this study is to assess the proportion of histologically abnormal appendices in patients undergoing colorectal cancer resection in a unit where standard of care is incidental appendectomy, with consent, when left colon or rectal cancer resection is performed.\u003c/p\u003e"},{"header":"Materials \u0026 Methods","content":"\u003cp\u003e This is a retrospective single-centre study on a prospectively collected data base of 717 consecutive patients undergoing colorectal cancer resection between January 2015 and June 2021.The data is based on service delivery and assessment, and thus does not require formal review by the Institutional Review Board.\u003c/p\u003e \u003cp\u003eIt is standard of care in our unit to perform incidental appendectomy, with fully informed consent, when left colon or rectal cancer resection is performed based on previous publications in this field [\u003cspan additionalcitationids=\"CR8 CR9\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIncidental appendectomy is defined as the removal of a macroscopically normal looking vermiform appendix whilst performing another abdominal operation.\u003c/p\u003e \u003cp\u003eConsecutive patients comprised two groups, those undergoing colorectal cancer resection with right hemicolectomy, extended-right hemicolectomy or sub-total colectomy which incorporates appendectomy, and patients undergoing left-sided resection (left-hemicolectomy, anterior resection or abdomino-perineal excision) with incidental appendectomy. Patients with known primary and metastatic appendix neoplasia were excluded.\u003c/p\u003e \u003cp\u003eThe primary tumours of the appendix include epithelial and non-epithelial tumours. An epithelial tumour can be benign (the muscularis mucosae is intact), such as tubular, tubulo-villous, villous adenoma or serrated polyp, or malignant, including low grade appendiceal mucinous neoplasm (LAMN), high-grade appendiceal mucinous neoplasm (HAMN), mucinous adenocarcinoma, signet-ring cell adenocarcinoma, and non-mucinous intestinal-type adenocarcinoma. The non-epithelial tumours include carcinoid tumours and mesenchymal tumours [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eDemographics, American Society of Anaesthesiologists (ASA) Physical Status Classification System and the open/laparoscopic approach were reviewed.\u003c/p\u003e \u003cp\u003eHistopathology reports were retrieved from hospital records. The proportion who had previous appendicectomy and those who had the appendix left in situ at left colon or rectal resection were recorded.\u003c/p\u003e \u003cp\u003eAll patients were discussed at the colorectal cancer multidisciplinary team meeting (MDT). When a neoplasm of the appendix was reported by the pathologist, a formal referral was made to the dedicated peritoneal malignancy MDT in case of an epithelial appendiceal neoplasm, or to the carcinoid MDT in case of a neuro-endocrine tumour, to establish a definitive management or surveillance plan.\u003c/p\u003e \u003cp\u003eThe study period of 5.5 years was considered an appropriate interval within which to achieve a meaningful number of cases to assess study outcomes.\u003c/p\u003e \u003cp\u003eThe primary outcome is the proportion of histologically abnormal appendix specimens at incidental appendectomy. Secondary outcome was specific complications from incidental appendectomy.\u003c/p\u003e \u003cp\u003eData were collected in an Excel spreadsheet. The analyses were performed using the statistical software STATA (College Station, Texas). Median values and interquartile range (IQR) were considered for continuous variables as their value distribution was skewed. Pearson's chi-square test was applied for analysis of categorical variables. The level of statistical significance was set at p\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eThe median age of the 717 patients included was 70 years (IQR: 62\u0026ndash;77 years) and 422/717(59%) were male.\u003c/p\u003e\n\u003cp\u003eOverall, 36(5%), 502(70%), 177(24.7%), and 2(0.3%) patients were ASA 1, 2, 3, and 4, respectively. The laparoscopic approach was used in 438/717(61%) operations.\u003c/p\u003e\n\u003cp\u003eA total of 91(13%) patients had previous appendectomy. In the right-sided resection group, 37/271(14%) had previous appendectomy vs. 54/446(12%) in the left-sided resection group. In 50/446(11%) patients undergoing left sided or rectal resection the appendix was not removed due to technical difficulties or where consent had not been documented.\u003c/p\u003e\n\u003cp\u003eThe appendix was available for histopathological analysis in 576/717(80%) patients undergoing colorectal cancer surgery. Of these, 234/576(41%) had a right hemicolectomy, extended-right hemicolectomy or sub-total colectomy which incorporates appendectomy. The remaining 342/576(59%) had left-sided resection (left-hemicolectomy, anterior resection or abdomino-perineal excision) with incidental appendectomy.\u003c/p\u003e\n\u003cp\u003eAt definitive histology, 534/576(92.7%) had a normal appendix. The remaining 42/576(7.3%) showed abnormal findings, including: 14/576(2.4%) inflammatory appendix pathology, 2/576(0.3%) endometriosis, 8/576(1.4%) hyperplastic polyp, and 18/576(3.1%) appendix tumours, which encompassed 6 LAMN, 3 carcinoids and 9 serrated polyps.\u003c/p\u003e\n\u003cp\u003eIn the 342 patients who had incidental appendectomy, 10(2.9%) had a neoplasm (2 LAMN, 3 carcinoids and 5 serrated polyps).\u003c/p\u003e\n\u003cp\u003eThe definitive histology of the appendix specimen in patients having right-sided resection or sub-total colectomy vs. patients having left-sided resection and incidental appendectomy showed no substantial differences (Table \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e\n\u003cp\u003e\u003cimg src=\"https://myfiles.space/user_files/122228_c8a1650c59388082/122228_custom_files/img1686730267.png\"\u003e\u003cbr\u003e\u003c/p\u003e\n\u003cp\u003eExcluding patients who had previous appendectomy, the proportion of appendixes left in place during left-sided resection was double when the laparoscopic approach was adopted, 39/247(16%) vs. 11/145(8%) in open procedures (p\u0026thinsp;=\u0026thinsp;0.019).\u003c/p\u003e\n\u003cp\u003eThere were no complications attributable to appendectomy.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe decision on whether to remove a normal looking appendix during colorectal cancer resection should be based on the likelihood of finding incidental appendix pathology and prevention of future appendix pathology balanced against the safety of the procedure. The current data demonstrates that 42/576 (7.3%) of incidental appendectomy specimens had abnormal findings at definitive histology with 18/42 (43%) having a tumour, including 6 LAMN, 3 carcinoids and 9 serrated polyps.\u003c/p\u003e \u003cp\u003eThe prevalence of appendix tumours in appendicectomy specimens has been reported in recent large series to be between 0.8%-1.4% [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. These data are mainly based on patients who have appendectomy for appendicitis, with little data on appendix pathology at incidental appendectomy for macroscopically normal-looking appendices. In this series,1.6% of patients overall had an appendix malignant tumour, with 1.5% when considering only incidental appendectomy during left-sided colorectal resection. Similarly, 1.6% of patients had a premalignant appendix tumour (i.e.: serrated polyp), with 1.5% when considering only incidental appendectomy during left-sided colorectal resection.\u003c/p\u003e \u003cp\u003eThe rates of appendiceal pathology reported here may seem higher than observed in generic colorectal resection practice. This is undoubtedly due to a department interest in appendix tumours with dedicated pathologists prepared to analyse the appendix, even if part of a right hemicolectomy specimen.\u003c/p\u003e \u003cp\u003eHistorically, the most common primary appendiceal tumour diagnosed after appendectomy for appendicitis was carcinoid in up to 85%, with epithelial appendix neoplasms in about 20% [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. In this report the most common tumour type was a LAMN. It is now well established that ruptured appendiceal epithelial neoplasms are the predominant cause of pseudomyxoma peritonei (PMP) [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e] and removal of a non-ruptured appendiceal tumour can abolish the risk of subsequent PMP development.\u003c/p\u003e \u003cp\u003eIn a patient where a carcinoid tumour is accidentally found in the specimen, appendicectomy alone is adequate treatment for tumours\u0026thinsp;\u0026lt;\u0026thinsp;1cm in diameter where complete resection has been achieved. For tumours measuring between 1 and 2cm in diameter, right hemicolectomy is selectively advocated, particularly with high-risk features such as mesoappendix invasion\u0026thinsp;\u0026gt;\u0026thinsp;3mm, presence of angioinvasion, and Grade 2 histology. For tumours\u0026thinsp;\u0026gt;\u0026thinsp;2cm in diameter, due to a greater risk of nodal involvement, right hemicolectomy is recommended [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eSeventeen appendix specimens (2.9%) were found to contain polyps, including serrated polyps (1.5%) and hyperplastic polyps (1.4%).\u003c/p\u003e \u003cp\u003eSerrated polyps are histologically similar to the sessile serrated lesions of the colon and rectum [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. However, it has been shown that the molecular pathological changes are different from those found in colorectal lesions. In particular, KRAS mutations are more common and BRAF mutations less common in appendiceal serrated polyps, reflecting the fact that the serrated pathway in the appendix is probably different from that in the colon and rectum [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. Although appendix serrated polyps are rare lesions, published series report an association of appendiceal serrated polyps with appendicitis and malignant progression [\u003cspan additionalcitationids=\"CR17\" citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Serrated polyps are pre-cancerous lesions and differentiating them from hyperplastic polyps is clinically important. Rubio et al [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e] previously warned about aggressiveness of serrated polyps and Chezar at al [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e] more recently published data suggesting that at least a subset of LAMNs may arise from a precursor serrated polyp.\u003c/p\u003e \u003cp\u003eHyperplastic polyps tend to be overall rarer in the appendix compared with the incidence in the colon and rectum [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e] and are commonly benign lesions.\u003c/p\u003e \u003cp\u003eOver 2% of patients in this series showed evidence of inflammatory changes in the appendix. It is unclear if this finding reflects a potential higher future risk of developing appendicitis, if the appendix was left in situ. Appendicitis is a common problem and approximately 40,000 people are admitted to hospital in England annually with appendicitis and it has been estimated that the lifetime risk of appendicitis is approximately 1 in 13 [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. We propose that preventing future appendicitis in patients having major resectional cancer surgery is beneficial to avoid potential diagnostic dilemmas and significant technical difficulties should a subsequent appendicectomy be required.\u003c/p\u003e \u003cp\u003eIn patients with endometriosis, the appendix seems to be involved in 2.6% [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. However, as our data confirm, endometriosis is quite rare in incidental appendicectomy specimens [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eWe did not encounter any complications attributable to appendectomy. There are some reasonable concerns about the risk of adding morbidity when an appendectomy is performed. This may be more of an issue at a laparoscopic procedure for left-sided colon or rectal cancer where, performing an appendectomy may be more complex due to suboptimal positioning of the ports and fatigue of the operating team. Thus, the laparoscopic approach was associated with a higher number of non-removal of the appendix.\u003c/p\u003e \u003cp\u003eThere is uncertainty regarding a possible increased risk of wound infection when an appendectomy is added during a \u0026ldquo;clean\u0026rdquo; procedure such as cholecystectomy or hysterectomy, and the literature is quite controversial [\u003cspan additionalcitationids=\"CR23\" citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. However, preforming an appendectomy during a potentially contaminated operation, such as colorectal resection, is unlikely to be an additional risk of wound infection.\u003c/p\u003e \u003cp\u003eRecently there have been reports on the effect of appendectomy in determining changes in the colonic microbiome [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. Research in this field is ongoing and still in its infancy. Further studies are needed to clarify the short- and long-term implications of microbiome changes related to appendectomy. It is unclear what effect incidental appendicectomy would have on the specific population in the present study undergoing surgery for a colorectal cancer with a median age of 70 years.\u003c/p\u003e \u003cp\u003eThe main limitations of the study are related to the retrospective design and single-centre setting.\u003c/p\u003e \u003cp\u003ePatients undergoing left sided colorectal cancer surgery with an appendix in situ may benefit from co-incidental appendectomy to treat the small proportion with synchronous neoplasms, polyps and inflammation and eradicate the risk of metachronous appendicitis, or a subsequent appendix tumour.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eConflicts:\u0026nbsp;\u003c/strong\u003eThe authors have no conflict of interest to disclose\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding:\u0026nbsp;\u003c/strong\u003eNo source of funding\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors Contributions:\u003c/strong\u003e All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Francesco Di Fabio, Prabhu Ravi, Niccolo Allievi, Kashuf Khan, and Abu Abduelraheim. The first draft of the manuscript was written by Francesco Di Fabio and Brendan Moran and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eLesi O, Walton SJ, Ballanamada Appaiah NN, Rasheed N, Dahanayaka J, Ideawor P, Saad Abdalla Al-Zawi A (2021) Prevalence of Carcinoma in Appendectomy Specimens for Patients Presenting With Acute Appendicitis: A Single-Center Study. Cureus 13:e19611.\u003c/li\u003e\n\u003cli\u003eO\u0026apos;Donnell ME, Badger SA, Beattie GC, Carson J, Garstin WI (2007) Malignant neoplasms of the appendix. Int J Colorectal Dis 22:1239-48.\u003c/li\u003e\n\u003cli\u003eConnor SJ, Hanna GB, Frizelle FA (1998) Appendiceal tumors: retrospective clinicopathologic analysis of appendiceal tumors from 7970 appendectomies. Dis Colon Rectum 41:75\u0026ndash;80.\u003c/li\u003e\n\u003cli\u003eMurphy EM, Farquharson SM, Moran BJ (2006) Management of an unexpected appendiceal neoplasm. Br J Surg 93:783-92.\u003c/li\u003e\n\u003cli\u003ePeltrini R, Cantoni V, Green R, Lionetti R, D\u0026apos;Ambra M, Bartolini C, De Luca M, Bracale U, Cuocolo A, Corcione F (2021) Risk of appendiceal neoplasm after interval appendectomy for complicated appendicitis: A systematic review and meta-analysis. Surgeon 19:e549-e558. \u003c/li\u003e\n\u003cli\u003eHayes D, Reiter S, Hagen E, Lucas G, Chu I, Mu\u0026ntilde;iz T, Martinez R (2021) Is interval appendectomy really needed? A closer look at neoplasm rates in adult patients undergoing interval appendectomy after complicated appendicitis. Surg Endosc 35:3855-3860.\u003c/li\u003e\n\u003cli\u003eKhan MN, Moran BJ (2007) Four percent of patients undergoing colorectal cancer surgery may have synchronous appendiceal neoplasia. Dis Colon Rectum 50:1856-9.\u003c/li\u003e\n\u003cli\u003eExner R, Sachsenmaier M, Horvath Z, Stift A (2012) Incidental appendectomy--standard or unnecessary additional trauma in surgery for colorectal cancer? A retrospective analysis of histological findings in 380 specimens. Colorectal Dis 14:1262-6.\u003c/li\u003e\n\u003cli\u003eVoitk AJ, Lowry JB (1988) Is incidental appendectomy a safe practice? Can J Surg 31:448-51.\u003c/li\u003e\n\u003cli\u003eSong JY, Yordan E, Rotman C (2009) Incidental appendectomy during endoscopic surgery. JSLS 13:376-83.\u003c/li\u003e\n\u003cli\u003eCarr NJ, Bibeau F, Bradley RF, Dartigues P, Feakins RM, Geisinger KR, Gui X, Isaac S, Milione M, Misdraji J, Pai RK, Rodriguez-Justo M, Sobin LH, van Velthuysen MF, Yantiss RK (2017) The histopathological classification, diagnosis and differential diagnosis of mucinous appendiceal neoplasms, appendiceal adenocarcinomas and pseudomyxoma peritonei. Histopathology 71:847-858.\u003c/li\u003e\n\u003cli\u003eCarr NJ (2020) Updates in Appendix Pathology: The Precarious Cutting Edge. Surg Pathol Clin 13:469-484.\u003c/li\u003e\n\u003cli\u003eAnsari N, Chandrakumaran K, Dayal S, Mohamed F, Cecil TD, Moran BJ (2016) Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy in 1000 patients with perforated appendiceal epithelial tumours. Eur J Surg Oncol 42:1035-41.\u003c/li\u003e\n\u003cli\u003eUK and Ireland Neuroendocrine Tumour Society guidelines. www.ukinets.org.\u003c/li\u003e\n\u003cli\u003ePai RK, Hartman DJ, Gonzalo DH, et al (2014) Serrated lesions of the appendix frequently harbor KRAS mutations and not BRAF mutations indicating a distinctly different serrated neoplastic pathway in the appendix. Hum Pathol 45:227\u0026ndash;35.\u003c/li\u003e\n\u003cli\u003eChezar K, Minoo P (2022) Appendiceal sessile serrated lesions are distinct from their right-sided colonic counterparts and may be precursors for appendiceal mucinous neoplasms. Hum Pathol 122:40-49.\u003c/li\u003e\n\u003cli\u003eRubio CA (2004) Serrated adenomas of the appendix. J Clin Pathol 57:946-9.\u003c/li\u003e\n\u003cli\u003eMartinez CA, Cutovoi J, Rossi DH, Meirelles LR, Ayrizono Mde L, Leal RF, Coy CS (2015) Intramucosal carcinoma of the appendix arising from traditional serrated adenoma. Case Rep Surg. 2015:297450.\u003c/li\u003e\n\u003cli\u003eNHS UK web site. https://www.nhs.uk/conditions/appendicitis/\u003c/li\u003e\n\u003cli\u003eMabrouk M, Raimondo D, Mastronardi M, Raimondo I, Del Forno S, Arena A, Sutherland N, Borgia A, Mattioli G, Terzano P, Seracchioli R (2020) Endometriosis of the Appendix: When to Predict and How to Manage-A Multivariate Analysis of 1935 Endometriosis Cases. J Minim Invasive Gynecol 27:100-106. \u003c/li\u003e\n\u003cli\u003eKlingbeil KD, Azab B, Moller MG (2017) Low-grade appendiceal mucinous neoplasm and endometriosis of the appendix. World J Surg Oncol 15:226.\u003c/li\u003e\n\u003cli\u003eSalom EM, Schey D, Pe\u0026ntilde;alver M, G\u0026oacute;mez-Mar\u0026iacute;n O, Lambrou N, Almeida Z, Mendez L (2003) The safety of incidental appendectomy at the time of abdominal hysterectomy. Am J Obstet Gynecol 189:1563-7; discussion 1567-8.\u003c/li\u003e\n\u003cli\u003eHuerta CT, Sundin A, Ribieras AJ, Saberi R, Ramsey W, Gilna G, Quiroz HJ, Thorson CM, Sola JE, Perez EA (2022) Nationwide outcomes of incidental appendectomy during cholecystectomy versus cholecystectomy alone in children: a propensity score-matched analysis. Pediatr Surg Int 38:1413-1420. \u003c/li\u003e\n\u003cli\u003eWarren JL, Penberthy LT, Addiss DG, McBean AM (1993) Appendectomy incidental to cholecystectomy among elderly Medicare beneficiaries. Surg Gynecol Obstet 177: 288\u0026ndash;94. \u003c/li\u003e\n\u003cli\u003eS\u0026aacute;nchez-Alcoholado L, Fern\u0026aacute;ndez-Garc\u0026iacute;a JC, Guti\u0026eacute;rrez-Repiso C at al (2020) Incidental Prophylactic Appendectomy Is Associated with a Profound Microbial Dysbiosis in the Long-Term. Microorganisms 23;8:609. \u003c/li\u003e\n\u003c/ol\u003e\n"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"incidental appendectomy, appendix tumour, LAMN, carcinoid","lastPublishedDoi":"10.21203/rs.3.rs-3035795/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-3035795/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003ePurpose\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe risk to benefit balance of incidental appendectomy in patients undergoing left colorectal cancer resection is unclear. The aim is to assess the proportion of histologically abnormal appendices in patients undergoing colorectal cancer resection in a unit where standard of care is appendectomy, with consent, when left-sided resection is performed.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eRetrospective study on prospectively collected database, conducted in a single tertiary-care centre.\u003cstrong\u003e \u003c/strong\u003eOverall,\u003cstrong\u003e \u003c/strong\u003e717 consecutive patients undergoing colorectal cancer resection between January 2015 and June 2021 were analysed. The primary outcome was the proportion of histologically abnormal appendix specimens at incidental appendectomy. Secondary outcome was complications from incidental appendectomy.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eOverall, 576/717(80%) patients had appendectomy at colorectal cancer surgery. In total, 234/576(41%) had a right-/extended-right hemicolectomy or sub-total colectomy which incorporates appendectomy, and 342/576(59%) had left-sided resection (left-hemicolectomy, anterior resection or abdomino-perineal excision) with incidental appendectomy.\u003c/p\u003e\n\u003cp\u003eAt definitive histology, 534/576(92.7%) had a normal appendix. The remaining 42/576(7.3%) showed abnormal findings, including: 14/576(2.4%) inflammatory appendix pathology, 2/576(0.3%) endometriosis, 8/576(1.4%) hyperplastic polyp, and 18/576(3.1%) appendix tumours, which encompassed 6 low-grade appendiceal mucinous neoplasms (LAMN), 3 carcinoids and 9 serrated polyps.\u003c/p\u003e\n\u003cp\u003eIn the 342 patients who had incidental appendectomy, 10(2.9%) had a neoplasm (2 LAMN, 3 carcinoids and 5 serrated polyps). There were no complications attributable to appendectomy.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ePatients undergoing left sided colorectal cancer surgery with an appendix in situ may benefit from a co-incidental appendectomy to treat the small proportion of synchronous neoplasms and eradicate the risk of metachronous appendicitis or a subsequent appendix tumour.\u003c/p\u003e","manuscriptTitle":"Occult appendix pathology in patients undergoing colorectal cancer resection: is there a role for incidental appendectomy?","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2023-06-14 08:17:27","doi":"10.21203/rs.3.rs-3035795/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"7d1d9b22-ccd2-4dd6-8334-f129050815a6","owner":[],"postedDate":"June 14th, 2023","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2023-06-15T19:29:23+00:00","versionOfRecord":[],"versionCreatedAt":"2023-06-14 08:17:27","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-3035795","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-3035795","identity":"rs-3035795","version":["v1"]},"buildId":"afDZ1USd8LLqUjqjB8QhT","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}