SP9.1.5 Occult appendix pathology in patients undergoing colorectal cancer resection suggests a role for appendectomy at left colon or rectal cancer resection

Abstract

Abstract Aims There is epidemiological evidence suggesting that the incidence of appendicular neoplasms is increasing. The purpose of this study is to assess the incidence of appendix neoplasms in patients undergoing colorectal cancer resection in a unit where standard of care is appendectomy, with consent, when left colon or rectal cancer resection is performed. Methods This is a retrospective single-centre study on a prospectively collected data base of 718 consecutive patients undergoing colorectal cancer resection between January 2015 and June 2021. The primary outcome was the proportion of histologically abnormal appendix specimens at incidental appendectomy. Secondary outcome was complications from incidental appendectomy. Results Overall, 222/718(31%) patients had previous appendectomy. The remaining 496 comprised 169/496 (34%) who had a right-/extended-right hemicolectomy or sub-total colectomy which incorporates appendectomy, and 327/496(66%) who had left-sided resection (left-hemicolectomy, anterior resection or abdomino-perineal excision) with incidental appendectomy. At definitive histology, 454(92%) had a normal appendix, 13(2.6%) had inflammatory appendix pathology, 17(3.4%) had a hyperplastic/serrated polyp and 12(2.4%) had an appendix neoplasm, which included 5 carcinoids and 7 low-grade appendiceal mucinous neoplasms (LAMN). In the 327 patients who had incidental appendectomy, 7(2.1%) had a neoplasm (4 carcinoid and 3 LAMN). There were no complications attributable to appendectomy. Conclusion Patients undergoing left sided colorectal cancer surgery with an appendix in situ should be counselled on the benefits of co-incidental appendectomy to treat the small proportion with synchronous neoplasms and inflammation and eradicate the risk of metachronous appendicitis or a subsequent appendix tumour.