Chemoprevention of development of colonic adenomatosis and carcinomatosis with intrarectal dose of 5-FU on animal model.

This study concerns the treatment by chemotherapy of carcinogenically-induced cancers in the colons of rats. These cancers mimic adenomatosis and carcinomatosis in humans. We believed that they could be prevented or regulated from growing into grossly visible tumors by the intrarectal administration of 5-fluorouracil if the treatment was started on nascent cancers. The incidence of colon carcinoma and the number of tumors per rat were significantly lower in rats treated by this method than in the control rats. Furthermore, some of the small tumors visible by endoscopy disappeared with treatment. This beneficial effect appeared to be due to the direct delivery of an active form of anticancer drug administered in high concentration to the target lesions in the colon mucosa, and carried fewer side effects when compared to other parenteral administrations.