External Validation of University of California, San Francisco, Cancer of the Prostate Risk Assessment Score

Objectives: In 2005, the University of California, San Francisco, proposed the Cancer of the Prostate Risk Assessment (UCSF-CAPRA) score to predict the risk of biochemical recurrence (BR) after radical prostatectomy. This study provides external validation and a modified version of the model using a large cohort of men treated with radical prostatectomy at a high-volume, tertiary referral center. Methods: From 1984 to 2006, 6737 men underwent radical prostatectomy at our institution for clinical Stage T1c-T3a prostate cancer with available follow-up information and no neoadjuvant or adjuvant therapy before BR. The BR-free survival was estimated using the Kaplan-Meier method and compared by UCSF-CAPRA score using the log-rank statistic. Performance of the UCSF-CAPRA was evaluated using Cox proportional hazards regression analysis and Harrell's concordance (c) index and compared with the Kattan nomogram. The UCSF-CAPRA score and final pathologic findings were assessed by odds ratios. Results: The 5-year BR-free survival rate was 83.1% overall and decreased from 94.4% for men with a UCSF-CAPRA score of 1 or less to 25.8% for those with a score of 7 or more (P <0.0001). The hazards ratio approximately doubled for each UCSF-CAPRA point until a score of 4, when the hazards ratio increased at a slower rate. The c-index of the UCSF-CAPRA and Kattan nomogram was 0.76 and 0.78, respectively. A greater UCSF-CAPRA score correlated with the final pathologic findings. Conclusions: The UCSF-CAPRA performed well in this tertiary, referral-based cohort with a c-index similar to that of the Kattan nomogram. It remains an effective prognostic instrument for predicting the risk of biochemical recurrence after radical prostatectomy.