Cholecystectomy and right-sided colon cancer: an epidemiological study.

The relation between prior cholecystectomy and right-sided colon cancer was investigated in a case-control study of 150 patients with histologically confirmed adenocarcinoma of the caecum or ascending colon and of two comparison groups. One comparison group consisted of 150 patients, matched for age, sex, and race, who had histologically confirmed adenocarcinoma of the descending or sigmoid colon and the other of 123 neighbourhood controls. Compared with left-sided cancer controls, the right-sided colon cancer cases had a relative risk of 1.87 for colon cancer after cholecystectomy. The relative risk was 1.86 when they were compared with the neighbourhood controls. When compared with both control groups relative risk was 1.77, with 95% confidence limits of 0.95 and 3.3 (p = 0.07). The increased risk of right-sided colon cancer after cholecystectomy may be associated with changes in biliary metabolism occurring after removal of a gall bladder.