[Bacillus of Calmette-Guérin immunotherapy: which protocol?]

Abstract

Several meta-analyses have reviewed the efficacy of bacille Calmette-Guérin (BCG) immunotherapy in treating nonmuscle-invasive bladder cancer (NMIBC). First, it was shown that BCG therapy was better than endoscopic resection alone in reducing the tumor progression rate, as long as a maintenance protocol was used. Moreover, BCG seems to be superior to mitomycin C in preventing recurrence. BCG has also proven its superiority over mitomycin C in terms of the risk for tumor progression when maintenance treatment is used. BCG maintenance treatment therefore seems to be the choice option to reduce the risk of both recurrence and tumor progression. The modalities for this treatment have not been clearly defined. Several protocols have been tested. Since its efficacy has been proven on a large cohort with randomized analysis, the SWOG protocol is currently the most widely used. It comprises six weekly instillations for the induction treatment, followed by three weekly instillations at 3, 6, 12, 18, 24, 30 and 36 months. It has been shown that BCG therapy toxicity was frequently the reason for interrupting maintenance therapy. In these patients with poor tolerance to the standard BCG dose, reducing the dose seems to be a useful option to improve BCG tolerance while preserving it efficacy. Finally, recent studies have shown that it would be preferable to adapt the dose and frequency of instillations of maintenance BCG to each patient. This individualized approach is undoubtedly BCG therapy's future.