Radical prostatectomy nomograms in black American men: accuracy and applicability

Abstract

Purpose: Nomograms have been developed to allow the prediction of disease recurrence based on clinical and pathological parameters in patients with clinically localized prostate cancer. However, they have been constructed using predominantly white American male (CAM) cohorts. We have previously shown that black American males (AAMs) have worse disease-free survival after radical prostatectomy after controlling for known prognostic factors. We tested the accuracy of prognostic nomograms in a population of AAMs with prostate cancer treated with radical prostatectomy.

Materials and methods: We tested the performance of published preoperative and postoperative prognostic nomograms in a cohort of patients treated with radical prostatectomy as monotherapy for localized prostate cancer at Wayne State University in the prostate specific antigen era. Predictions made with the nomogram were stratified by race and compared with actual outcomes. The summary statistic used to evaluate the nomogram was the concordance index. A value of 0.5 indicates no predictive discrimination, whereas a value of 1.0 indicates perfect discrimination.

Results: A total of 1,043 patients, including 331 AAMs (32%) and 712 CAMs (68%), comprised the study cohort. Treatment failure was defined as increasing prostate specific antigen, which occurred in 193 patients (18.5%). The preoperative concordance index for CAMs and AAMs was 0.78 and 0.74, respectively (p = 0.8). The postoperative index was 0.85 and 0.83, respectively (p = 0.9).

Conclusions: Preoperative and postoperative nomograms can be applied accurately to an individual regardless of race.