Effects of oral and rectal BCG administration on chemically-induced rat intestinal carcinoma

Intestinal carcinomas were induced by repeated subcutaneous injections of 1,2-dimethylhydrazine in syngereic BD-IX strain rats for 12 weeks. At the end of the treatment, one group received 2 doses of 50 mg BCG by a gastric tube, then a dose of 50 mg BCG by rectal instillation. The other group received no BCG. There was no significant difference in survival time, total number of cancers per rat, or cancer localization between the treated or untreated groups. Disseminated peritoneal metastases were more frequently found in BCG-treated animals. These results do not support the use of orally administered BCG in the treatment of human colorectal cancer.