Novel nomograms to predict recurrence and progression in primary non-muscle-invasive bladder cancer: validation of predictive efficacy in comparison with European Organization of Research and Treatment of Cancer scoring system

Abstract

Purpose To develop and validate novel nomograms to predict recurrence and progression after transurethral resection of bladder tumor (TURBT) in Korean patients with non-muscle-invasive bladder cancer (NMIBC). Methods We retrospectively analyzed the clinical data on 970 newly diagnosed NMIBC patients after TURBT between 2000 and 2013 in a single institution. We used multivariate Cox proportional hazard models to identify the significant predictors of recurrence and progression, which resulted in the construction of the nomograms predicting the 5-year probability of recurrence and progression. We internally validated the nomograms using the area under the receiver-operating characteristics' curves and calibration plots. In addition, the clinical usefulness of each nomogram was assessed and compared with that of the European Organization of Research and Treatment of Cancer (EORTC)-scoring system using decision curve analysis (DCA). Results The significant factors related to recurrence were gross hematuria at diagnosis, previous or concomitant upper urinary tract urothelial carcinoma (UTUC), pT1 tumor, high tumor grade, multiple tumors, and intravesical therapy. The significant predictors of progression were previous or concomitant UTUC, pT1 tumor, high tumor grade, carcinoma in situ, and lymphovascular invasion. The 5-year predictive accuracy of each nomogram was 65% for recurrence and 70% for progression, respectively. Compared with the EORTC-scoring system, the nomograms were generally well calibrated. On DCA, each nomogram presented better net benefit gains than did the EORTC-scoring system across a wide range of threshold probabilities. Conclusions Our novel nomograms are not completely accurate, but they show a reasonable level of discriminative ability, adequate calibration, and meaningful net benefit gain for the prediction of recurrence and progression after TURBT in Korean NMIBC patients. Additional external validation will be required to generalize the nomograms which we developed.