Purpose: Multivariate prognostic instruments aim to predict risk of recurrence among patients with localized prostate cancer. We devised a novel risk assessment tool which would be a strong predictor of outcome across various levels of risk, and which could be easily applied and intuitively understood.
Materials and methods: We studied 1,439 men diagnosed between 1992 and 2001 who had undergone radical prostatectomy and were followed in the Cancer of the Prostate Strategic Urologic Research Endeavor (CaPSURE) database, a longitudinal, community based disease registry of patients with prostate cancer. Disease recurrence was defined as prostate specific antigen (PSA) 0.2 ng/ml or greater on 2 consecutive occasions following prostatectomy or a second cancer treatment more than 6 months after surgery. The University of California, San Francisco-Cancer of the Prostate Risk Assessment (UCSF-CAPRA) score was developed using preoperative PSA, Gleason score, clinical T stage, biopsy results and age. The index was developed and validated using Cox proportional hazards and life table analyses.
Results: A total of 210 patients (15%) had recurrence, 145 by PSA criteria and 65 by second treatment. Based on the results of the Cox analysis, points were assigned based on PSA (0 to 4 points), Gleason score (0 to 3), T stage (0 to 1), age (0 to 1) and percent of biopsy positive cores (0 to 1). The UCSF-CAPRA score range is 0 to 10, with roughly double the risk of recurrence for each 2-point increase in score. Recurrence-free survival at 5 years ranged from 85% for a UCSF-CAPRA score of 0 to 1 (95% CI 73%-92%) to 8% for a score of 7 to 10 (95% CI 0%-28%). The concordance index for the UCSF-CAPRA score was 0.66.
Conclusions: The UCSF-CAPRA score is a straightforward yet powerful preoperative risk assessment tool. It must be externally validated in future studies.