Risk Stratification of Upper Urinary Tract Urothelial Carcinoma Patients for Survival Prediction: A Simple Summation Scoring Method

Purpose: To stratify upper urinary tract urothelial carcinoma (UTUC) patients into risk groups in terms of 5-year survival. Methods and materials: All potential UTUC patients recorded in our cancer registry database from 1997 to 2011 were evaluated for authentic presence of UTUC. Age at diagnosis, sex, organ involvement, dialysis, renal transplantation status, clinical stage, survival to the last follow-up, and the cause of death of each patient were recorded. All patients were randomized into a developmental set or a validation set at a 1:1 ratio. Survival prediction models and scores were developed using the developmental set and validated in terms of discrimination and calibration using the validation set. Patients were stratified into risk groups using the summed risk scores and their survival compared by the log rank test. Results: We enrolled 1,120 authentic UTUC patients. In the developmental set, older age, male sex, and higher clinical staging were significant predictors of 5-year death after controlling for other variables. Based on these three clinical variables, patients were stratified into low-, intermediate-, high-, and very high-risk groups using the summed risk scores. The 5-year all-cause and cancer-specific survivals of UTUC patients in the low-, intermediate-, high-, and very high-risk groups were 83.0% and 85.0%, 57.7% and 70.9%, 16.8% and 26.3%, and 2.2% and 7.5%, respectively (p < 0.001). Both discrimination and calibration were good for the validation set (overall concordance index = 0.762). Conclusions: Stratification of UTUC patients using summed risk scores was a simple and useful way to estimate survivals and to select appropriate treatments.