Assessment of Pathological Prostate Cancer Characteristics in Men with Favorable Biopsy Features on Predominantly Sextant Biopsy

Abstract

BackgroundThe rate of insignificant prostate cancer (IPCa) is increasing. ObjectivesTo examine three end points in patients with a single, positive core and no high-grade prostate cancer (PCa) at biopsy, namely (1) rate of clinical IPCa at radical prostatectomy (RP), defined as organ-confined PCa with a Gleason score of 6 or lower and tumor volume<0.5 cc; (2) rate of pathologically unfavorable PCa at RP (Gleason 7–10 or non-organ-confined disease); and (3) ability to predict either insignificant or unfavorable PCa at RP. Design, Setting, and ParticipantsRetrospective analysis of 209 men with one positive biopsy core showing Gleason 6 or lower. Measurements: Detailed clinical and RP data were used in multivariable logistic regression models. Their bias-corrected accuracy estimates were quantified using the area under the curve (AUC) method. Results and LimitationsAt RP, IPCa was present in 28 patients (13.4%) and pathologically unfavorable PCa, defined as Gleason 7 or higher or non-organ-confined PCa, was reported in 70 (33.5%) of 209 men; when Gleason 8 or higher or non-organ-confined PCa was considered, the proportion fell to 11%. Our multivariable models predicting different categories of pathologically unfavorable PCa at RP had an accuracy rate between 56% and 68% for predicting IPCa at RP versus 65.1% to 66.1% and 61.7% for the IPCa nomograms of Kattan et al and Nakanishi et al, respectively. Our data are not applicable to screening because they originate from a referral population. ConclusionsDespite highly favorable biopsy features, between 11% and 33% of men had unfavorable PCa at RP and only a minority (13.4%) had pathologically confirmed IPCa. Neither clinically insignificant nor pathologically unfavorable features could be predicted with sufficient accuracy for clinical decision making.