The association between cholecystectomy and the risk of colorectal cancer: an updated systematic review and meta-analysis of cohort studies

Background: The effect of cholecystectomy on the development of colorectal cancer (CRC) has prompted a large number of population-based studies. However, the results of these studies are debatable and inconclusive. Our aim in the present study was to conduct an updated systematic review and meta-analysis to explore the causality between cholecystectomy and CRC. Methods: Cohort studies published in the PubMed, Web of Science, Embase, Medline, and Cochrane databases up to May 2022 were retrieved. Pooled relative risks (RRs) and 95% confidence intervals (CIs) were analyzed using a random effects model. Results: Eighteen studies, involving 1,469,880 cholecystectomy and 2,356,238 non-cholecystectomy cases, were eligible for the final analysis. Cholecystectomy was not associated with the development of CRC (P=0.109), colon cancer (P=0.112), or rectal cancer (P=0.184). Subgroup analysis of sex, lag period, geographic region, and study quality revealed no significant differences in the relationship between cholecystectomy and CRC. Interestingly, cholecystectomy was significantly associated with right-sided colon cancer (RR =1.20, 95% CI: 1.04-1.38; P=0.010), especially in the cecum, the ascending colon and/or the hepatic flexure (RR =1.21, 95% CI: 1.05-1.40; P=0.007) but not in the transverse, descending, or sigmoid colon. Conclusions: Cholecystectomy has no effect on the risk of CRC overall, but a harmful effect on the risk of right-sided colon cancer proximally.