Bacillus Calmette-Guerin (BCG) therapy is safe and effective in non-muscle invasive bladder cancer (NMIBC) patients with immunomodulating conditions.

Introduction: Bacillus Calmette-Guerin (BCG) is the most effective therapy available to treat high-risk nonmuscle invasive bladder cancer (NMIBC) patients. However, for patients with immunomodulating conditions BCG is a relative contraindication due to efficacy and safety concerns. To our knowledge, no population-level study evaluating the efficacy and safety profile of BCG for immunomodulated patients exists.

Methods: NMIBC patients aged 66 years or older were identified in the Surveillance, Epidemiology, and End Results (SEER) - Medicare database from 1975-2013. All patients completed adequate BCG (at least 5 plus 2 treatments completed within 12 months of diagnosis). Two groups were defined: an immunomodulated population identified by immunomodulating conditions such as solid-organ transplantation, HIV, and autoimmune conditions, and an immunocompetent group. The primary endpoint was 5-year progression-free survival defined as progression to systemic chemotherapy, checkpoint inhibitors, radical or partial cystectomy, metastasis, or cancer-specific death. A safety analysis was performed as a secondary outcome.

Results: In a total of 4,277 patients with NMIBC who completed adequate BCG, 606 (14.2%) were immunomodulated. The immunomodulated group was older at diagnosis (P < 0.001), more likely to be female (P < 0.001), more likely to live in a metropolitan area (P < 0.001), and had higher Charlson comorbidity scores (P < 0.001). There were no differences in progression to chemotherapy (P = 0.17), checkpoint inhibitors (P > 0.99), radical cystectomy (P = 0.40), partial cystectomy (P = 0.93), metastasis (P = 0.19), cancer-specific death (P = 0.18) or 5-year total bladder cancer progression (P = 0.30) between the groups. For the safety analysis, rates of disseminated BCG were similar between immunomodulated and immunocompetent patients (0.7% vs. <1.8%, P = 0.51). On multivariable analysis 5-year total bladder cancer progression (HR 1.07 [CI 0.88-1.30]) was similar between the groups.

Conclusion: Rates of bladder cancer progression and disseminated BCG complications 5-years after BCG therapy were similar regardless of immunomodulation status. These findings suggest that BCG intravesical therapy can be offered to immunomodulated patients with high-risk NMIBC although theoretical infectious complication risks remain.