External validation of the CAPRA-S score to predict biochemical recurrence, metastasis and mortality after radical prostatectomy in a European cohort

PURPOSE: The Cancer of the Prostate Risk Assessment post-Surgical (CAPRA-S) score predicts prostate cancer (PCa) recurrence based on pathologic information from radical prostatectomy (RP). CAPRA-S has never been externally validated in a European cohort. We independently validated the CAPRA-S in a European, single-institution database.

MATERIALS AND METHODS: The study cohort comprised of 14532 patients treated with radical prostatectomy between January 1992 and August 2012. Prediction of biochemical recurrence (BCR), metastasis and cancer-specific mortality (CSM) by CAPRA-S was assessed by Kaplan-Meier analysis and the c-index. Performance of CAPRA-S in predicting BCR was assessed by calibration plot and decision curve analysis.

RESULTS: Median follow up was 50.8 months (IQR 25.0 - 96.0). BCR occurred in 20.3% of men at a median time of 21.2 mo (IQR 7.7 - 44.9). When stratifying patients by CAPRA-S risk groups, BCR-free survival estimates at 5 years were 91.4%, 70.4%, and 29.3% for the low, intermediate and high-risk group, respectively. The c-index for CAPRA-S in predicting BCR was 0.80. The c-indices for CAPRA-S in predicting metastasis and CSM were 0.85 and 0.88, respectively. 417 men developed metastasis, and 196 men died from PCa.

CONCLUSIONS: The postoperative CAPRA-S score was accurate when applied in a European study cohort and predicted biochemical recurrence, metastasis and CSM after RP with c-indices > 0.80. The score can be valuable for decision-making for adjuvant therapy.