Multi-institutional Validation of the CAPRA-S Score to Predict Disease Recurrence and Mortality After Radical Prostatectomy

Background: The University of California, San Francisco, Cancer of the Prostate Risk Assessment Postsurgical (CAPRA-S) score uses pathologic data from radical prostatectomy (RP) to predict prostate cancer recurrence and mortality. However, this clinical tool has never been validated externally. Objective: To validate CAPRA-S in a large, multi-institutional, external database. Design, setting, and participants: The Shared Equal Access Regional Cancer Hospital (SEARCH) database consists of 2892 men who underwent RP from 2001 to 2011. With a median follow-up of 58 mo, 2670men(92%) had complete data to calculate a CAPRA-S score. Intervention: RP. Outcome measurements and statistical analysis: The main outcome was biochemical recurrence. Performance of CAPRA-S in detecting recurrence was assessed and compared with a validated postoperative nomogram by concordance index (c-index), calibration plots, and decision curve analysis. Prediction of cancer-specific mortality was assessed by Kaplan-Meier analysis and the c-index. Results and limitations: The mean age was 62 yr (standard deviation: 6.3), and 34.3% of men had recurrence. The 5-yr progression-free probability for those patients with a CAPRA-S score of 0-2, 3-5, and 6-10 (defining low, intermediate, and high risk) was 72%, 39%, and 17%, respectively. The CAPRA-S c-index was 0.73 in this validation set, compared with a c-index of 0.72 for the Stephenson nomogram. Although CAPRA-S was optimistic in predicting the likelihood of being free of recurrence at 5 yr, it outperformed the Stephenson nomogram on both calibration plots and decision curve analysis. The cindex for predicting cancer-specific mortality was 0.85, with the caveat that this number is based on only 61 events. Conclusions: In this external validation, the CAPRA-S score predicted recurrence and mortality after RP with a c-index > 0.70. The score is an effective prognostic tool that may aid in determining the need for adjuvant therapy. (C) 2013 European Association of Urology. Published by Elsevier B. V. All rights reserved.