Prognostic significance of Bacillus Calmette-Guérin failure classification in non-muscle-invasive bladder cancer

Objective To investigate the differences in the clinical features and subsequent stage progression and disease-specific survival among patients with Bacillus Calmette-Guérin (BCG) failure, after dividing these patients into BCG-refractory, -resistant, -relapsing, and -intolerant groups. Patients and Methods We identified 173 patients with initial BCG failure from 521 patients who had undergone induction BCG therapy for non-muscle-invasive bladder cancer, excluding CIS, between 1987 and 2009. Patients were stratified into four BCG-failure groups, and each prognostic outcome was evaluated. Results Median follow-up period from initial BCG failure was 4.7 years. A total of 42 patients (24.3%) were stratified into the BCG-refractory, three (1.7%) into the BCG-resistant, 106 (61.3%) into the BCG-relapsing, and 22 (12.7%) into the BCG-intolerant group. Twenty-four patients (13.9%) experienced stage progression during follow-up. Multivariate analysis showed that pathological G3 at BCG failure (P= 0.014; risk ratio 2.84) and BCG-refractory (P < 0.001; risk ratio 4.68) were independent predictors for stage progression. The 10-year progression-free survival rates were 53.2%, 91.1% and 93.8% in the BCG-refractory, BCG-relapsing and BCG-intolerant groups, respectively. The stage progression rate was higher in the BCG-refractory than in the BCG-relapsing (P < 0.001) and BCG-intolerant (P= 0.007) groups. Similarly, the 10-year disease-specific survival rate in the BCG-refractory group was significantly worse than those in the other BCG failure groups (P < 0.001). Conclusions Stratification of BCG failure into the above-mentioned four groups can identify patients with BCG-failure in terms of their prognosis. The potential risk for critical adverse events was higher in the BCG-refractory group than in the other BCG-failure groups, despite the fact that patients in each group all underwent induction BCG therapy, therefore, treatment decisions, protocols and recommendations should be established based on each individual BCG-failure pattern.