Letter to the Editor: Bacillus Calmette-Guerin (BCG) Treatment Failures with Non-Muscle Invasive Bladder Cancer: A Data-Driven Definition for BCG Unresponsive Disease

Objective: To create the first data-driven definition for those unlikely to benefit from further BCG treatment. Materials and Methods: The database created for the Phase 2 BCG-Interferon-α 2B (IFN) study was queried and BCG failure patients were identified (n = 334). Full study protocols have previously been published. Separate models were constructed for analysis of patients with any CIS (pure or concomitant) and pure papillary disease. Variables considered included age, gender, stage, grade, tumor size and focality (for papillary only), number of prior BCG courses, and prior BCG failure interval. Results: Patients with recurrent CIS within 6 months of their most recent prior BCG course (HR 2.56, p <  0.01) and ≥2 prior BCG failures (HR 1.54, p <  0.01) responded worst to repeat intravesical therapy. Those with CIS recurrence at 6-12 months did not differ from those recurring within 6 months (HR = 0.88, p = 0.71). Patients with recurrent papillary disease within 6 months (HR 1.82, p = 0.02), ≥2 BCG failures (HR 1.54, p = 0.03), and multifocal disease (HR 2.05, p <  0.01) responded worst to therapy. Patients with T1 disease remained disease free in 38% of cases (24-51% 95% CI) at 2 years with low rates of progression. Conclusions: Patients who fail two courses of BCG with either persistent or recurrent multifocal papillary disease within 6 months or CIS within 12 months of their prior BCG should be considered BCG unresponsive. Recurrent T1 disease respond reasonably well to another course with low progression rates but further investigation is warranted.