Gallstones, cholecystectomy and the risk of pancreatic cancer: an updated systematic review and meta-analysis of cohort studies.

The effect of gallstones and cholecystectomy on the development of pancreatic cancer has recently prompted many population-based studies. However, the results are controversial. We conducted an updated systematic review and meta-analysis to explore the causality among gallstones, cholecystectomy and pancreatic cancer. Cohort studies published in the PubMed, Web of Science, Embase, and Cochrane Library databases up to May 2023 were retrieved. Pooled relative risks (RRs) and 95% confidence intervals (CIs) were analyzed using a random-effects model. We screened 1391 articles and included 16 studies. Gallstones were not associated with an increased risk of pancreatic cancer ( P  = 0.082), with only the Asian population ( P  = 0.011) showing an increased risk in the subgroup analysis. A markedly higher risk of pancreatic cancer was observed among patients with cholecystectomy (RR = 1.23; 95% CI, 1.07-1.41; P  = 0.004; I 2  = 74.4%). The association remained significant in the Asian population ( P  = 0.004), in the subgroup analyses stratified by sex, lag period, and time interval since cholecystectomy, and when the models were adjusted for diabetes, smoking, and BMI. Interestingly, cholecystectomy due to gallstones (RR = 1.30; 95% CI, 1.14-1.48; P  < 0.001; I 2  = 30.8%), rather than for unspecified reasons ( P  = 0.116), markedly increased the risk of pancreatic cancer. In conclusion, cholecystectomy due to gallstones, rather than gallstone formation, conferred an increased risk for pancreatic cancer. There was a higher risk for the Asian population for both gallstones and cholecystectomy.