BCG treatment of existing Ta, T1 tumours or carcinoma in situ of the bladder.

There are theoretical limits to the efficacy of intravesical instillation of anticancer agents as a method to prevent recurrence of superficial bladder cancer. Studies on the direct efficacy of intravesical instillation of bacillus Calmette-Guérin (BCG) to treat existing papillary tumours (Ta, T1) have shown a complete response rate of 66.4% and a partial response rate of 20.8%. These figures represent potent efficacy similar to that of BCG in the treatment of carcinoma in situ (CIS). Moreover, this efficacy was found to persist over a long period of time, and the subsequent recurrence rate was markedly reduced. In cases with multiple tumours, or in subjects where concurrent CIS is strongly suspected, these findings suggest that intravesical instillation of BCG might best be performed prior to transurethral resection of bladder tumours.