Intravesical bacille Calmette-Guérin versus mitomycin C in superficial bladder cancer: formal meta-analysis of comparative studies on tumor progression.

OBJECTIVES: To compare the therapeutic efficacy of intravesical bacille Calmette-Guérin (BCG) with mitomycin C (MMC) on progression of Stage Ta and T1 bladder carcinoma.
METHODS: Combined published and unpublished data from comparative studies on BCG versus MMC in superficial bladder carcinoma were analyzed, considering possible confounding factors. Odds ratios (ORs) and 95% confidence intervals (CIs) were used as the primary effect size estimate. Tumor progression was defined as progression to a higher tumor stage or the development of metastatic disease.
RESULTS: In nine eligible clinical trials, 1277 patients were treated with BCG and 1133 with MMC. Within the overall median follow-up of 26 months, 7.67% of the patients in the BCG group and 9.44% of the patients in the MMC group developed tumor progression. In all nine individual studies and in the combined results, no statistically significant difference in the ORs for progression between the BCG and MMC-treated groups was found (combined OR = 0.77; 95% CI 0.57 to 1.03; P = 0.081). In the subgroup with BCG maintenance, the combined result of the five individual studies showed a statistically significant superiority of BCG over MMC (OR = 0.66; 95% CI 0.47 to 0.94; P = 0.02). In the four studies without BCG maintenance, the combined result indicated no statistically significant difference between the two treatments (OR = 1.16; 95% CI 0.65 to 2.07; P = 0.612). Potential confounders, such as tumor risk status, duration of follow-up, BCG strain, BCG and MMC treatment regimen, and year of publication did not significantly influence these results.
CONCLUSIONS: The results demonstrated statistically significant superiority for BCG compared with MMC for the prevention of tumor progression only if BCG maintenance therapy was provided.