Niwa N, et al. - This trial was conducted to determine if switching the bacillus Calmette-Guerin (BCG) strain during the second induction course of BCG therapy had a therapeutic benefit in patients with tumor recurrence after the initial BCG therapy (BCG-relapsing tumor). The same BCG strain as administered during initial BCG therapy can be utilized efficaciously for the second BCG therapy in patients with a BCG-relapsing tumor following the initial BCG therapy. Patients treated with BCG Tokyo-172 for an initial tumor had with a higher incidence of side effects during the second BCG therapy using the same strain.