Association of appendectomy with colorectal cancer: a systematic review and meta-analysis

Background: Appendectomy is a common surgical procedure done worldwide. The appendix is known as a sanctuary for commensal organisms in the gut, and an inflamed appendix may alter the gut microbiome, leading to inflammation and oncogenesis. An association between appendectomy and subsequent colorectal cancer development has been postulated; however, previous studies have differed in study design and results. Method: We performed a systematic review and meta-analysis of studies evaluating the association between appendectomy and colorectal cancer in adults. A literature search of MEDLINE and EMBASE was conducted through September 2022. Search terms included “appendectomy” and “colon cancer” or “rectal cancer” or “colorectal cancer.” Odds ratios and sensitivity analyses were calculated. Result: Of the 541 studies identified in our search, 10 studies met our inclusion criteria. The eight papers that studied the association between appendectomy and colorectal cancer reported no association with the odds ratio (OR) of 1.30 (0.92, 1.83). However, studies on the association of appendectomy and proximal versus distal colon cancer reported a statistically significant increase in proximal colon cancer compared to distal colon cancer OR of 1.48 (1.29, 1.69). Conclusion: Our study demonstrates that appendectomy is associated with the development of proximal colon cancer but not distal colon cancer. Relevance for patients: Patients who have had an appendectomy should be aware of the potentially increased risk for colon cancer. Consequently, they should provide this information during routine clinic visits, especially if they are having gastrointestinal symptoms.