Do colon and rectum exhibit an opposite cancer risk trend versus cholecystectomy? A case--double control study.

A case-double control study on 318 personally interviewed patients with large bowel neoplasia has been carried out to establish the possible role of cholecystectomy in the development of colorectal cancer. The dietary habits both of the cancer patients and control subjects were investigated. All controls were considered free of neoplastic lesions on the basis of a negative fecal occult blood test. Data from the study showed that the prevalence of cholecystectomy in the overall patients was similar to that of the two control groups. However, analysing the data for colon and rectum, the relative risk of colonic cancer after cholecystectomy was significantly increased in males (RR = 2.75; p less than 0.05), whereas that of rectal cancer appeared to be decreased in females (RR = 0.18; p less than 0.02). Subsite analysis demonstrated that right-sided neoplasia after long-standing cholecystectomy (greater than or equal to 10 years) was responsible for the increased colonic risk. In conclusion, the present data support the hypothesis that cholecystectomy may be considered a risk factor for right-sided colon cancer, but indicate that this operation seems to play a protective role for rectal cancer.