Does switching the bacillus Calmette-Guérin strain affect clinical outcome in patients with recurrent non-muscle-invasive bladder cancer after initial bacillus Calmette-Guérin therapy?

PURPOSE: It is still unknown whether switching the bacillus Calmette-Guérin (BCG) strain at the second induction course of BCG therapy has a therapeutic benefit in patients with tumor recurrence after the initial BCG therapy (BCG-relapsing tumor).

MATERIALS AND METHODS: We retrospectively reviewed the clinicopathological features of 97 patients treated with a second induction course of BCG therapy between 1986 and 2014. Among the patients initially treated with BCG Tokyo-172, the second course was either BCG Tokyo-172 in 56 (57.8%) or BCG Connaught in 15 (15.5%). Among those who were initially treated with BCG Connaught, the corresponding numbers were 13 (13.4%) or 13 (13.4%), respectively. Twenty-eight (28.9%) patients were given a different BCG strain at the 2 BCG therapies (switching group), and 69 (71.1%) patients were given the same BCG strain (non-switching group).

RESULT: The 5-year recurrence-free survival rate of the switching group was 64.7 ± 9.6%, which was not significantly different from that of the non-switching group (54.8 ± 6.9%, P = 0.427). Switching or not switching the BCG strain was not significantly associated with tumor recurrence after the second BCG therapy. The 5-year progression-free survival rate of the switching group was 95.4 ± 2.6%, which was also not significantly different from that of the non-switching group (96.0 ± 3.9%, P = 0.674). Patients treated with BCG Tokyo-172 to Tokyo-172 had significantly higher incidences of side effects during the second BCG therapy.

CONCLUSIONS: The results of this study indicate that in patients with a BCG-relapsing tumor after the initial BCG therapy, the same BCG strain as that administered at the initial BCG therapy could be utilized effectively for the second BCG therapy. Patients treated with BCG Tokyo-172 for an initial tumor had a higher incidence of side effects during the second BCG therapy using the same strain.