Urinary biomarkers for immunotherapy response in urothelial carcinoma: current status and future outlook.

[INTRODUCTION] Immunotherapy treatments, such as intravesical Bacillus Calmette-Guérin (BCG) for non-muscle invasive bladder cancer (NMIBC) and systemic immune checkpoint inhibitors (ICIs) for all stages are central to the management of urothelial carcinoma (UC). Biomarkers that are prognostic or predictive and that help in monitoring these therapies are needed to guide and improve efficacy and tolerability. In this review, we evaluated the current landscape of urinary biomarkers for predicting response to immunotherapy (BCG and ICIs) in UC patients and their potential to guide personalized treatment strategies.

[AREAS COVERED] This narrative review summarizes current evidence on urinary biomarkers for predicting responses to BCG and ICIs therapies in UC, based on a comprehensive search of PubMed literature.

[EXPERT OPINION] Urinary biomarkers show significant potential for transforming UC immunotherapy by facilitating personalized treatment. Despite promising initial data for various analytes, large-scale validation and standardization must be addressed. We still need better, faster, easier, cheaper, reliable and valid urine-based biomarkers. Future research should focus on multiplex panels to enhance patient stratification and improve therapeutic outcomes and follow-up.