Gallbladder Removal Raises Colon Cancer Risk

NEW YORK (Reuters Health) - Gallbladder removal or "cholecystectomy" raises the risk of colon but not rectal cancer, results of a UK study suggest. Still, experts note that the risk is only slightly increased and, therefore, should not influence the decision to undergo this procedure if it's necessary.

The findings support the view of previous studies on the link between gallbladder removal and colon cancer, investigators note in the American Journal of Gastroenterology.

According to Drs. Theresa Shao and Yu-Xiao Yang from the University of Pennsylvania School of Medicine in Philadelphia, stone-forming bile could be the underlying mechanism.

It is hypothesized, they explain, that increased exposure of the colon lining to bile acids and undigested fat following cholecystectomy may lead to damage that ultimately results ini cancer. The suggestion that cholecystectomy raises the risk of colon but not rectal cancer is consistent with the bile acid exposure theory.

Shao and Yang analyzed data from more than 600,000 subjects who were entered in the UK General Practice Research Database to assess the risk of colorectal cancer after cholecystectomy. The findings suggest that if 10,000 people who underwent the surgery, were followed for 10 years, 119 would develop colon cancer. By contrast, among subjects who did not undergo cholecystectomy, the number was slightly lower -- 86.

Simply having gallstones raised the risk of colon cancer to a similar degree as cholecystectomy, which also supports the bile acid exposure theory.

The researchers caution, however, that "for an individual patient, such a modest risk increase should weigh little in the decision to undergo elective cholecystectomy."

"However, owing to the high prevalence of gallstone disease and cholecystectomy in the general population, even an association of relatively small magnitude could have important public health implications," they write.

SOURCE: American Journal of Gastroenterology, August 2005.