[BCG and bladder cancer: Past, present and future.]

Area of Science:

• Urology
• Immunology
• Oncology

Background:

• Bacillus Calmette-Guérin (BCG) has been a cornerstone in non-muscle-invasive bladder cancer (NMIBC) treatment for over four decades.
• Its precise mechanisms of action remain incompletely understood despite extensive research.

Purpose of the Study:

• To summarize current knowledge on BCG's efficacy, administration, and role in NMIBC management.
• To highlight the importance of maintenance therapy and explore future research directions.

Main Methods:

• Review of clinical and basic research on BCG therapy for NMIBC.
• Analysis of data regarding administration routes, comparative efficacy, adverse events, and prognostic factors.

Main Results:

• Intravesical BCG is superior to intracavitary chemotherapy for preventing NMIBC recurrence but has worse adverse events.
• BCG can delay or prevent progression to invasive cancer, particularly with maintenance therapy for intermediate and high-risk cases.
• No significant efficacy differences exist between BCG strains, but dose variations impact recurrence rates. Side effects do not predict efficacy, and maintenance therapy does not significantly increase toxicity.

Conclusions:

• BCG immunotherapy is recommended for intermediate and high-risk NMIBC.
• Maintenance therapy is essential for maximizing BCG's benefits in preventing cancer progression.
• Future research should focus on defining optimal individualised schedules and doses, and evaluating alternative therapies due to BCG shortages.