Clinical utility of percent-positive prostate biopsies in. predicting biochemical outcome after radical prostatectomy or external-beam radiation therapy for patients with clinically localized prostate cancer

Background and Purpose: The clinical utility of the percentage of positive prostate biopsies in predicting prostate specific antigen (PSA) outcome aft er radical prostatectomy (RP) or external-beam radiation therapy (EBRT) for men with PSA-detected or palpable prostate cancer is not established. Methods: A Cox regression multivariable analysis was used to determine whet her percent-positive prostate biopsies provided clinically relevant informa tion about PSA outcome after RP in 960 men, while accounting for the previo usly established risk groups based on the pretreatment PSA concentration bi opsy Gleason score, and the 1992 American Joint Commission on Cancer clinic al T stage. Results: In the intermediate-risk group, 80% of the patients (stage T-2b or biopsy Gleason 7 or PSA 10-20 ng/mL) could be classified into either an 11 % or an 86% 4-year PSA control cohort using the preoperative prostate biops y data. These findings were validated using an independent surgical (N = 82 3) and radiation (N = 473) data set. Percent-positive prostate biopsies add ed clinically significant information regarding time to PSA failure after R P, Conclusions: The percentage of positive prostate biopsies should be conside red in conjunction with the PSA level, biopsy Gleason score, and clinical T stage when counseling patients with newly diagnosed and clinically localiz ed prostate cancer about PSA outcome after RF or EBRT,