Inhibition of experimental bladder tumor induction by systemic BCG treatment.

: Transitional cell carcinoma of the urinary bladder was induced in rats by ingestion of 0.188% N-[4-5-nitro-2-furyl)-2-thiazolyl] formamide. During the induction period of 8 months, one animal group received systemic BCG treatment. After 12 months, the BCG-treated rats showed a significantly lower bladder tumor weight and stage than the corresponding controls. The results are discussed with regard to the possibility of BCG prophylaxis of human bladder tumors.