CHOLECYSTECTOMY / COLON CANCER

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CHOLECYSTECTOMY/COLON CANCER

Two recent studies suggest that removal of the gallbladder may increase the

risk of colon cancer. Cholecystectomy apparently almost doubled the risk of

cancer of the right colon according to a University of Pittsburgh study.

The researchers feel that the higher concentrations of certain bile acids which

reach the colon may induce the cancer.

These bile acids and their by-products induce cancer or serve as co-carcinogens

in laboratory animals. (The Lancet 2:379, August 22, 1981; The Lancet 2:381,

August 22, 1981)

http://www.tagnet.org/abstracts/v2n1.htm

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October 12, 2001

Epidemiology

Cholecystectomy increases risk of GI cancers

http://www.huntsmancancer.org/content/reuters/2001/10/12/20011012epid002.html

Last Updated: 2001-10-12 10:16:14 EDT (Reuters Health)

WESTPORT, CT (Reuters Health) - Cholecystectomy, but not cholelithiasis in the

absence of surgery, increases the risk for intestinal and esophageal cancers,

according to two reports by Swedish investigators. Their data suggest that

increased exposure to bile may be the underlying mechanism for the increased

risk.

Dr. Jesper Lagergren, of Karolinska Institutet in Stockholm, and associates

examined the Swedish Inpatient Register and identified 278,460 patients who

underwent cholecystectomy between 1965 and 1997. They report their findings in

the September issue of Gastroenterology.

During a mean follow-up of 12.1 years, the increased risk was highest in areas

closest to the common bile duct. For the proximal small bowel, the standardized

incidence ratio (SIR) was 1.77 compared with the expected number of incident

cancers in the Swedish population. For the cecum and ascending colon, the SIR

was 1.16, and for the transverse colon it was 1.05.

The gradient of risk was more pronounced among patients whose surgery included

the common bile duct. In such cases, the SIR increased to 3.14 for the proximal

small bowel, but was lower, 1.50, for the distal small bowel, and 1.04 for the

cecum and ascending colon.

After removal of the gallbladder, " the concentration of bile is increased

locally in the small bowel, particularly in the proximal part, " the

investigators note. An additional source of risk may be " bacterial degradation

of bile salts to secondary bile acids [that] might be pathogenic to the

intestinal mucosa, " they posit.

In their second study, Dr. Lagergren's group conducted a similar analysis of

adenocarcinoma of the esophagus in cholecystectomized patients. Over a mean

follow-up period of 13 years, 53 patients developed adenocarcinoma of the

esophagus, while the expected number was 38. The risk increased with age, with

a SIR of 1.2 for those below 60 years of age and 1.4 for those 60 years or

older.

" The larger volume of bile after cholecystectomy could overload the clearing

capacity of the proximal duodenum and thereby cause duodenogastric reflux

through the pylorus, " Dr. Lagergren's team speculates.

These findings suggest " the need for considering bile reflux when planning the

treatment of patients with gastroesophageal reflux disease, " the researchers

conclude.

Gastroenterology 2001;131:542-547,548-553.

-Westport Newsroom 203 319 2700

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