The effect of cholecystectomy on the induction of colorectal tumors in mice by 1,2-dimethylhydrazine.

The influence of previous cholecystectomy (CCE) on the 1,2-dimethylhydrazine (DMH)-induced colorectal tumorigenesis was examined in 497 female NMRI mice after 14, 20, 24, 28, 33, and 36 weeks of induction time. There were only minor differences between the cholecystectomized and the non-cholecystectomized animals with regard to the percentage of tumor-bearing animals, number of adenomas, and location of the tumors. Only after an induction time of 20 weeks, the operated group had significantly more carcinoma-bearing animals than the non-operated group (P less than 0.01, chi 2-test). The implication of these results on known data of epidemiologic studies in human colorectal cancer are discussed.