Occult appendix pathology in patients undergoing colorectal cancer resection and prophylactic appendectomy

The risk-benefit balance of prophylactic appendectomy in patients undergoing left colorectal cancer resection is unclear. The aim of this report 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.

A retrospective study on a prospectively collected database was conducted in a single tertiary-care center. Overall, 717 consecutive patients undergoing colorectal cancer resection between January 2015 and June 2021 were analyzed. The primary outcome was the proportion of histologically abnormal appendix specimens at prophylactic appendectomy. The secondary outcome was complications from prophylactic appendectomy.

Overall, 576/717 (80%) patients had appendectomy at colorectal cancer surgery. In total, 234/576 (41%) had a right-/extended-right hemicolectomy or subtotal colectomy which incorporates appendectomy, and 342/576 (59%) had left-sided resection (left-hemicolectomy, anterior resection or abdominoperineal excision) with prophylactic 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 tumors, which encompassed six low-grade appendiceal mucinous neoplasms (LAMNs), three carcinoids, and nine serrated polyps. In the 342 patients who had prophylactic appendectomy, 10 (2.9%) had a neoplasm (two LAMN, three carcinoids, and five serrated polyps). There were no complications attributable to appendectomy.

Occult appendix pathology in patients undergoing colorectal cancer resection is uncommon when prophylactic appendectomy was performed. However, approximately 3% of patients had a synchronous appendix neoplasm.