Does cholecystectomy predispose to colorectal cancer? A case control study.

A case-control study of 598 patients with colorectal cancer (296 men, 302 women) admitted from January 1974 to October 1983 was undertaken. Patients were matched for age and sex, with controls admitted for unrelated conditions. All information was obtained from the hospital records. In men, there was no evidence of an increased risk of colonic cancer after cholecystectomy relative to men without cholecystectomy. There was some evidence of an increased risk in women (relative risk = 1.7; 95 percent confidence interval, 1.0 to 3.1) and this was highest when the tumor was in the right colon (P less than 0.005). This study confirms previous observations that cholecystectomy leads to an increased risk of right-sided colonic tumors in women but not in men. The apparent difference between the sexes may be explained by the low rate of cholecystectomy in the men examined.