Adjuvant intravesical instillation for primary T1G3 bladder cancer: BCG versus MMC in Korea

To compare the efficacy of bacillus Calmette-Guerin (BCG) and mitomycin-C (MMC) intravesical instillation for primary T1G3 bladder cancer (BC).

This retrospective study included 107 patients with newly diagnosed primary T1G3 BC who were treated by transurethral resection (TUR) plus intravesical instillation. The BCG group was administered BCG-RIVM (2×10(8) colony forming unit) instilled once weekly for 6 weeks, or the same regimen as induction therapy followed by three once-weekly instillations at 3, 6, 12 and 18 months after initiation of the induction therapy. The MMC group was administered MMC (30 mg) in six weekly instillations, or the same regimen with subsequent monthly instillations for one year. We evaluated differences between these agents in disease recurrence-free survival and disease progression rate at the time of recurrence.

The mean observation period was 24.3±28.6 months. The BCG and MMC groups comprised 53 patients (49.5%) and 54 patients (50.5%), respectively. During the observation period, recurrences developed in 61 patients (57.0%). The median time to recurrence for the BCG and MMC arm were 24.0 and 26.0 months, respectively. There were no significant differences for recurrence-free survival between the two groups (log-rank p=0.616). At the time of recurrence, 9.4% (5 out of 53) of patients in the BCG arm and 7.4% (4 out of 54) patients in the MMC arm also experienced by disease progression (p=1.000).

There were no statistically significant differences regarding recurrence and disease progression rate at the time of recurrence between the two adjuvant treatments in primary T1G3 BC. Thus, large prospective studies in Asian population are required.