Sufficient prophylactic efficacy with minor adverse effects by intravesical instillation of low-dose bacillus Calmette-Guérin for superficial bladder cancer recurrence

BACKGROUND: Intravesical instillation of bacillus Calmette-Guérin (BCG) is the most efficient strategy for prophylaxis of superficial bladder cancer recurrence. Adverse effects of BCG are major obstacles, but the reduction of BCG dose could minimize these effects. The efficacy and adverse effects of half-dose (40 mg) BCG, Tokyo 172 strain, were prospectively evaluated. METHODS: A total of 93 patients with superficial bladder cancer (pTa or pT1) were sequentially assigned to receive either 40 or 80 mg of BCG after transurethral resection. BCG was administered weekly for 6 weeks postoperatively. Eighty patients observed longer than 12 months after BCG therapy (41, 40 mg group; 39, 80 mg group) were analyzed. RESULTS: BCG therapy course was completed in 71 patients. Tumor recurrence was recognized in 11 of 40 patients in the 40 mg group and in 5 of 31 patients in the 80 mg group. There was no significant difference in tumor recurrence rate between the two groups (P = 0.547). BCG therapy was withdrawn in 1 patient in the 40 mg group and in 8 patients in the 80 mg-group because of BCG-related adverse effects. The morbidity of BCG-related toxicity was significantly higher in the 80 mg group. CONCLUSION: Half-dose of BCG Tokyo 172 strain had a similar efficacy and its toxicity was significantly lower compared to the standard dose. Thus, half-dose of this strain might be suitable, at least for initial BCG therapy, for the prophylaxis of bladder cancer recurrence. Further study would be necessary to clarify the efficacy of low-dose instillation in high-risk patients.