August 29, 2005

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

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.