Background: Intravesical instillation therapy of Bacillus Calmette-Guérin (BCG) has become a standard treatment for carcinoma in situ (CIS) of the urinary bladder. However, there have been few reports concerning the direct effect of BCG on existing tumors classified as Ta or T1. In the first stage of this clinical study, 157 patients were treated with BCG intravesical instillation (Tokyo 172 strain [BCG Co. Ltd., Tokyo, Japan]; 80 mg weekly for eight times) by our Study Group. The efficacy on existing tumors was a complete response (CR) rate of 84.4% and 66.4% and a partial response (PR) of 6.3% and 20.8% for 32 cases of CIS and 125 cases of Ta or T1 tumors, respectively.
Methods: In the second stage of this study, the authors investigated the outcome of the 138 patients who had achieved CR or PR in the first stage. One hundred twenty (87.0%) of the patients were followed fully. Of those patients, 52 were randomized to receive prophylactic (maintenance) therapy consisting of BCG of 40 mg monthly for 12 times (Group A), whereas 55 were randomized to an untreated control group (Group B). Thirteen other patients refused to be randomized and were followed without prophylactic instillation.
Results: The median follow-up period was 48 months for Group A and 42 months for Group B. In Groups A and B, the beneficial effect of the BCG therapeutic instillation persisted for a long time, and the 3-year nonrecurrence rate was 77.6% in Group A and 74.2% in Group B. Disease progression was observed rarely.
Conclusion: For patients in whom transurethral resection of tumors of the bladder (TUR-Bt) alone is unlikely to eliminate the tumor, intravesical BCG is potentially the treatment of choice.