Evaluation of a low-dose intravesical bacillus Calmette-Guérin (Tokyo strain) therapy for superficial bladder cancer.

To examine whether intravesical instillation of low-dose bacillus Calmette-Guérin (BCG) therapy is effective with low toxicity, we reviewed data for 111 patients with superficial bladder cancer (stages Ta and T1). Among them, 74 received the BCG treatment for prophylaxis of intravesical recurrence after transurethral resection, and the remaining 37 therapeutically for Ta or T1 tumours. The patients were divided into two groups by instillation dose of BCG (Tokyo 172 strain): 40 mg (n = 55) and 80 mg (n = 56), and statistically compared for recurrence, antitumour effect and toxicity. The mean instillations were done 8.4 times in the 40 mg dose group and 8.6 times in the 80 mg dose group. Among the 74 patients with BCG therapy for prophylaxis those with a previous episode of bladder cancer treatment (n = 47) experienced a significantly (p = 0.006) shorter recurrence-free interval than those with no episode (n = 27). Among 47 patients with a previous treatment episode, those receiving the 80 mg dose demonstrated a significantly longer recurrence-free interval than those given the 40 mg dose (p = 0.03). Among the 27 patients without previous treatment no significant difference in recurrence-free intervals was found between the two dose groups. Univariate and multivariate analyses using Cox's proportional hazards model confirmed the above findings. The recurrence index was also significantly reduced after BCG therapy in the 80 mg and 40 mg groups and similar antitumour effects for Ta or T1 tumours were observed in the two dose groups. The degree of toxicity due to BCG therapy was significantly (p = 0.02) lower with the 40 mg dose. The present study suggests that (1) a 40 mg BCG low-dose (Tokyo 172 strain) regimen is useful for preventing recurrence, with sufficient therapeutic efficacy and low frequency of toxicity, among patients without a previous treatment, and (2) prophylactic effects with the 80 mg dose regimen are much superior for previous treatment cases.