Purpose of review: Bacillus Calmette-Guérin (BCG) is the standard immune therapy for nonmuscle invasive bladder cancer. A systematic review of published articles regarding BCG treatment of bladder cancer was conducted and a commentary of these is provided to gain a perspective of the current major developments in the field.
Recent findings: Several BCG strains are utilized worldwide. As the understanding of genetic and phenotypic differences in these strains is elucidated, inquiries into the potential clinical effects of these various strains have been studied. Data suggest that some strains could be more effective than others but further study is needed. Although response to BCG is heterogenous, current clinical practice does not incorporate use of biomarkers to delegate treatment selection. Thus, biomarker prediction is an important area of research in this area. Novel urine and tissue markers show promise in this endeavor. Notable publications also include mechanistic studies showing a role for T cells, natural killer cells, mast cells, and granulocytes in BCG's antitumor efficacy.
Summary: Significant developments have occurred in understanding BCG's response and mechanism of action, which remains incompletely understood. Future work includes efforts to create recombinant BCG strains to decrease side effects, repeated instillations, and increase overall efficacy.