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.