Intravesical bacillus Calmette-Guerin versus mitomycin C for superficial bladder cancer: A formal meta-analysis of comparative studies on recurrence and toxicity

Purpose: We compare the therapeutic efficacy and toxicity of intravesical bacillus Calmette-Guerin (BCG) with mitomycin C on recurrence of stages Ta and T1 bladder carcinoma. Materials and Methods: Combined published and unpublished data from comparative studies on BCG versus mitomycin C for superficial bladder carcinoma considering possible confounding factors were analyzed. Odds ratio (OR) and its 95% Cl were used as primary effect size estimate. Toxicity data were evaluated descriptively. Results: In 11 eligible clinical trials 1,421 patients were treated with BCG and 1,328 were treated with mitomycin C. Within the overall median followup time of 26 months 38.6% of the patients in the BCG group and 46.4% of those in the mitomycin C group had tumor recurrence. In 7 of 11 studies BCG was significantly superior to mitomycin C, in 3 studies no significant difference was found, while in 1 study mitomycin C was significantly superior to BCG. An overall statistically significant superiority of BCG versus mitomycin C efficacy in reducing tumor recurrence was detected (OR 0.56, 95% CI 0.38 to 0.84, p = 0.005). In the subgroup treated with BCG maintenance all 6 individual studies showed a significant superiority of BCG over mitomycin C (OR, 0.43, 95% CI 0.35 to 0.53, p <0.001). In 4 of the 5 studies with reported,data on toxicity BCG associated cystitis was significantly more frequent than in the mitomycin C group (53.8% versus 39.2%). The combined cystitis OR was 1.81 (95% CI 1.48 to 2.23, p <0.001). The OR for cystitis in the BCG maintenance group did not significantly differ from that in the nonmaintenance therapy group. Conclusions: The results suggest superiority of BCG over mitomycin C for prevention of tumor recurrences in the combined data and particularly in the BCG maintenance treatment subgroup, irrespective of the actual (intermediate or high) tumor risk status. The toxicity with BCG is higher but does not differ between BCG maintenance and nonmaintenance groups.