Incidence of and mortality from Bacille Calmette-Guérin (BCG) infections after BCG instillation therapy

Objectives: To investigate the incidence of and mortality associated with Bacille Calmette-Guérin (BCG) infections in a Finnish population of patients with bladder cancer treated with BCG instillations. Materials and Methods: We conducted a nationwide register study and identified patients with BCG infections in Finland during 1996 to 2016 using the Finnish Cancer Registry and the Finnish National Infectious Diseases Register. We estimated the number of patients treated with BCG instillations based on data on national consumed BCG doses used to treat patients with bladder cancer, and calculated the annual incidence proportion of BCG infections. We further performed a detailed medical chart review to describe the clinical features and outcomes of the treated BCG infections. Results: In total, 87 patients with BCG infection after BCG treatment of bladder cancer were identified. The incidence proportion increased gradually, yielding a cumulative incidence proportion of 2.5% during the latter half of the study period. BCG infections led to significant mortality, with 10% overall mortality and 17.5% mortality from systemic infections, which is notably higher than previously reported. Conclusion: The incidence proportion of BCG infections among bladder cancer patients treated with BCG has increased in Finland up to 2.5% at a nationwide level, with a notably higher mortality rate than previously reported.