[Types of surgical operations and cancer development]

Experimental and clinical studies were undertaken to examine whether carcinogenesis in particular organs is influenced by types of surgical operations resulting in an alteration of bile acid excretion and metabolism. A higher incidence of remnant gastric carcinoma was noted in rats receiving gastrectomy with a greater amount of duodenogastric reflux. Furthermore, carcinogenesis was enhanced in gastrectomized rats that had been fed on a high-cholesterol diet causing an increase in bile acid excretion. In a human study, however, there was no relationship between gastrectomy and the incidence of remnant stomach carcinoma. Intestinal surgery alters bile acid metabolism, which may promote colon carcinogenesis. In patients receiving ileocecal resection or right hemicolectomy, the amount of total fecal bile acids was markedly increased as compared to the normal controls. A retrospective study on the incidence of metachronous colorectal cancer in our department showed that the incidence was 12.2% in patients with ileocecal resection in contrast to 4.4% in those with left-side colon resection. These findings suggest that there is a relationship between previous ileocecal resection and the development of metachronous colon carcinoma. We could not obtain any evidence of cholecystectomy having an increased risk for the development of colorectal carcinoma.