THE UNIVERSITY OF CALIFORNIA, SAN FRANCISCO CANCER OF THE PROSTATE RISK ASSESSMENT SCORE: A STRAIGHTFORWARD AND RELIABLE PREOPERATIVE PREDICTOR OF DISEASE RECURRENCE AFTER RADICAL PROSTATECTOMY

Abstract

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. 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. 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. The UCSF-CAPRA score is a straightforward yet powerful preoperative risk assessment tool. It must be externally validated in future studies.