Relative risk of colorectal cancer after cholecystectomy. A multicentre case-control study.

The relative risk of developing colorectal cancer after cholecystectomy was assessed retrospectively in 493 patients with colorectal cancer (239 women, 254 men). The results were compared with a control group of patients matched for sex and age. The overall relative risk was 0.7 (90% confidence interval, 0.7-0.8). However, when the data were analysed for site significant differences were seen. In the caecum and ascending colon the relative risk of developing colorectal cancer after cholecystectomy was 2.8 (90% confidence interval, 1.0-9.4). In the rectum the relative risk was only 0.3 (90% confidence interval, 0.2-0.6) in both sexes. The results suggest a relative increased risk of developing right-sided colon cancer after cholecystectomy in women. However, they only partially support the hypothesis that prior cholecystectomy increases the relative risk of developing colorectal cancer in view of the data relating to the rectum.