Prediction models for progression of non‐muscle‐invasive bladder cancer: A review

An accurate prediction of progression is critically important in the management of non‐muscle‐invasive bladder cancer. At present, three risk models are widely known for prediction of the risk of tumor recurrence and progression of non‐muscle‐invasive bladder cancer: the European Organization for Research and Treatment of Cancer, Club Urológico Español de Tratamiento Oncológico, and new European Organization for Research and Treatment of Cancer models. Bladder neck involvement has been shown to be one of the significant predictors for progression in non‐muscle‐invasive bladder cancer, and a new scoring model (Tokyo Medical and Dental University model) consisting of bladder neck involvement, tumor grade, and stage has been developed and externally validated. However, the predictive abilities of these models are still unsatisfactory, and more precise models are necessary for accurate individual prediction of prognosis. Until now, time‐fixed analysis has been used for most studies predicting the prognosis and outcome of non‐muscle‐invasive bladder cancer patients. In order to predict progression more precisely, time‐dependent models should be developed using multiple‐event analytical techniques, as non‐muscle‐invasive bladder cancer often progresses to muscle‐invasive bladder cancer after multiple recurrences and changes in tumor characteristics over a long natural history. Integration of molecular markers is also a promising approach. A validated model that accurately predicts the risk of progression would help urologists and patients decide whether and when to choose radical cystectomy on an individual basis.