Objective: To assess, in a systematic review, the effectiveness of intravesical bacillus Calmette-Guérin (BCG) in preventing tumour recurrence in patients with medium/high risk Ta and T1 bladder cancer.
Patients and methods: An electronic database search of Medline, Embase, DARE, the Cochrane Library, Cancerlit, Healthstar and BIDS was undertaken, plus hand searching of the Proceedings of ASCO, for randomized controlled trials, in any language, comparing transurethral resection (TUR) alone with TUR followed by intravesical BCG in patients with Ta and T1 bladder cancer.
Results: The search identified 26 publications comparing TUR with TUR + BCG. Six trials were considered acceptable, representing 585 eligible patients, 281 in the TUR-alone group and 304 in the TUR + BCG group. The major clinical outcome chosen was tumour recurrence. The weighted mean log hazard ratio for the first recurrence, taken across all six trials, was -0.83 (95% confidence interval -0.57 to -1.08, P < 0.001), which is equivalent to a 56% reduction in the hazard, attributable to BCG. The Peto odds ratio for patients recurring at 12 months was 0.3 (95% confidence interval of 0.21-0.43, P < 0.001), significantly favouring BCG therapy. Manageable toxicities associated with intravesical BCG were cystitis (67%), haematuria (23%), fever (25%) and urinary frequency (71%). No BCG-induced deaths were reported.
Conclusion: TUR with intravesical BCG provides a significantly better prophylaxis of tumour recurrence in Ta and T1 bladder cancer than TUR alone. Randomized trials are still needed to address the issues of BCG strain, dose and schedule, and to better quantify the effect on progression to invasive disease.