Intestinal cancer after cholecystectomy: Is bile involved in carcinogenesis?

Background & Aims: Results concerning an association between cholecystectom y and right-sided colon cancer are inconsistent. Little is known about the relation between cholecystectomy and small bowel cancer. Therefore, we eval uated cholecystectomy and risk of bowel cancer. Methods: Cholecystectomized patients, identified through the Swedish Inpatient Register, from 1965 thr ough 1997, were followed up for subsequent cancer. The standardized inciden ce ratio (SIR) estimated relative risk. Results: In total, 278,460 cholecys tectomized patients, contributing 3,519,682 person-years, were followed up for a maximum of 33 years after surgery. Cholecystectomized patients had an increased risk of proximal intestinal adenocarcinoma, which gradually decl ined with increasing distance from the common bile duct. The risk was signi ficantly increased for adenocarcinoma (SIR, 1.77; 95% confidence interval [ CI], 1.37-2.24) and carcinoids of the small bowel (SIR, 1.71; 95% Cl, :1.39 -2.08), and right-sided colon cancer (SIR, 1.16; 95% Cl, :1.08-1.24). No as sociation was found with more distal bowel cancer. The gradient was further pronounced when surgery of the common bile duct was included. The associat ions remained increased up to 33 years after cholecystectomy. No difference s between sexes were found. Conclusions: Cholecystectomy increases the risk of intestinal cancer, a risk that declines with increasing distance from t he common bile duct. Changes in the intestinal exposure to bile might be th e underlying biological mechanism.