Race and prostate weight as independent predictors for biochemical recurrence after radical prostatectomy

We hypothesized that factors beyond pathological stage, grade, PSA and margin status would be important predictors of biochemical recurrence (BCR) after radical prostatectomy (RP). A cohort of 3194 patients who underwent RP between 1988 and 2007 and who had neither neoadjuvant therapy nor postoperative adjuvant hormonal therapy was retrieved from the Duke Prostate Center database. Age, prostate-specific antigen (PSA), pathological Gleason score (pG), lymph node status, seminal vesicle invasion (SVI), extracapsular extension (ECE), positive surgical margin (PSM) status, year of surgery, race, adjuvant radiation therapy (XRT), percent tumor involvement in the RP specimen and prostate weight were evaluated as possible predictors of BCR in multivariate Cox regression analysis. BCR was defined as a PSA of 0.2 ng ml(-1) or higher at least 30 days after surgery. A nomogram was developed from the Cox model. Predictive accuracy was obtained by calculating bias-corrected Harrell's c and by bootstrap calibration. In multivariate analysis, PSA (hazard ratio 1.39 (95% confidence interval 1.29-1.51)), ECE (1.22 (1.04-1.44)), pG score (1.38 (1.14-1.68), 2.23 (1.76-2.84), 2.69 (2.12-3.40) for pG 3+4, 4+3, >7, respectively), SVI (1.72 (1.40-2.12)), PSM (2.05 (1.73-2.42)), year of surgery (0.65 (0.54-0.77)), African-American race (1.37 (1.13-1.66)), adjuvant XRT (0.19 (0.11-0.34)) and prostate weight (0.83 (0.76-0.92)) were identified as independent predictors of BCR (P< or =0.018 for all factors). Predictive accuracy of the nomogram was 0.75. Race and prostate weight were independent predictors for BCR after RP. By incorporating these variables, we developed a nomogram, which provides a highly accurate means for estimating risk of BCR after RP.