High-risk nonmuscle invasive bladder cancer: definition and epidemiology

Nonmuscle invasive bladder cancer represents a large majority of patients diagnosed with this disease. Precise definition and risk stratification are paramount in this group as high-risk patients have higher rates of progression and mortality and may benefit from early identification and aggressive treatment.

The mainstay definitions of high-risk nonmuscle invasive bladder cancer are based on grade and stage. Recently, efforts have been made to incorporate other clinical variables into multivariate risk assessment tools and nomograms to predict disease behavior and guide management. Variant histology and molecular biomarkers are being explored as tools to refine risk stratification; however, results are still preliminary and need validation.

Future research should concentrate on ways to better risk-stratify patients and identify early those that are most likely to recur and progress quickly. Topics of focus should be on better multivariate risk assessment tools and nomograms providing continuous scales and incorporating molecular markers with validation in large multi-institutional cohorts.