Intravesical immunotherapy in nonmuscle invasive bladder cancer

INTRODUCTION: Nonmuscle invasive urothelial cell carcinoma is the most frequent malignancy of the urinary bladder. The high recurrence rate (up to 80%) and risk of progression (up to 30%) reflect the need for long-term follow-up and sometimes multiple interventions. To reduce the rate of recurrences and tumor progression, intravesical immunotherapy, especially the use of Bacille Calmette-Guerin (BCG), represents the gold standard adjuvant treatment of high-risk nonmuscle invasive bladder cancer (NMIBC). This article reviews the role of BCG therapy and several promising new immunotherapeutic approaches such as mycobacterium phlei cell wall-nucleic acid complex, interleukin-10 (IL-10) antibody, vaccine-based therapy, alpha-emitter therapy, and photodynamic therapy checkpoint inhibitors. METHODS: A systematic literature review was performed using the terms (immunotherapy, NMIBC, BCG, and intravesical) using PubMed and Cochrane databases. RESULTS: BCG represents the most common intravesical immunotherapeutic agent for the adjuvant treatment of high-risk NMIBC. Its use is associated with a significant reduction of recurrence and progression. Patients with NMIBC of intermediate and high-risk benefit the most from BCG therapy. To achieve maximal efficacy, an induction therapy followed by a maintenance schedule should be used. Full-dose BCG is recommended to obtain ideal antitumoral activity and there is no evidence of a reduction of side effects in patients treated with a reduced dose. There are multiple new approaches and agents in immunotherapy with potential and promising antineoplastic effects. CONCLUSIONS: The beneficial effect of BCG is well documented and established. To reduce the tumor specific mortality, it is essential to follow guideline-based treatment. In patients with BCG-failure, there are new promising alternatives other than BCG but BCG remains the gold standard at this stage.