Multiinstitutional validation of the UCSF cancer of the prostate risk assessment for prediction of recurrence after radical prostatectomy

Abstract

The University of California, San Francisco (UCSF) Cancer of the Prostate Risk Assessment (CAPRA) is a novel preoperative index which predicts the risk of biochemical recurrence after radical prostatectomy. The performance of the index is at least as good as the best available instruments based on clinical variables, and the 0 to 10 score is simple to calculate for both clinical and research purposes. This study used a large external dataset to validate CAPRA. Data were abstracted from the Shared Equal Access Regional Cancer Hospital (SEARCH) database, a registry of men who underwent radical prostatectomy at 4 Veterans Affairs and 1 active military medical center. Of 2096 men in the database, 1346 (64%) had full data available to calculate the CAPRA score. Performance of the CAPRA score was assessed with proportional hazards regression, survival analysis, and the concordance (c) index. Of the studied patients, 41% were non-Caucasian, and their mean age was 62 years. Twenty-six percent suffered recurrence; median follow-up among patients who did not recur was 34 months. The hazard ratio (HR) for each 1-point increase in CAPRA was 1.39 (95% CI [confidence interval], 1.31-1.46). The 5-year recurrence-free survival rate ranged from 86% for CAPRA 0-1 patients to 21% for CAPRA 7-10 patients. Increasing CAPRA scores were significantly associated with increasing risk of adverse pathologic outcomes. The c-index for CAPRA for the validation set was 0.68, compared with 0.66 for the original development set. The UCSF-CAPRA accurately predicted both biochemical and pathologic outcomes after radical prostatectomy among a large, diverse, cohort of men. These results validated the effectiveness of this powerful and straightforward instrument.