Validity of the Cancer of the Prostate Risk Assessment Score Derived From Targeted Biopsy: Modeling Evidence From Ultrasound Lesion-Directed Biopsy

Abstract

ObjectiveOur aim was to evaluate the impact of direct, ultrasound lesion-targeted prostate biopsy, alone or in combination with systematic sampling, on prostate cancer risk prediction. Materials and MethodsWe reviewed biopsy findings for men with known or clinical suspicion of prostate cancer undergoing direct, ultrasound-targeted biopsy of radiographic lesions with concomitant systematic extended peripheral zone biopsy. We examined the resulting tumor volume estimates, Gleason grade, and Cancer of the Prostate Risk Assessment score generated from each strategy. Resulting multivariate clinical models of adverse surgical pathology—defined as high grade (Gleason pattern, ≥ 4+3) or non–organ-confined disease (≥ pT3a) were compared by the area under the Receiver Operating Characteristic curve. ResultsA total of 352 patients received ultrasound-targeted biopsy. At diagnosis, the mean age was 63 years, median prostate-specific antigen, 5.7 ng/mL (interquartile range, 4.3-8.2), and median 15 cores (interquartile range, 12-18). The addition of targeted cores to systematic biopsy resulted in reclassification of 52 patients (14.7%) based on Gleason score, 45 (12.8%) by percentage of cores involved > 33%, and 51 (14.5%) by single core positivity > 50%; Cancer of the Prostate Risk Assessment risk category increased in 44 (12.5%). In multivariable logistic regression models of 196 men treated with prostatectomy, the area under the Receiver Operating Characteristic curve for the prediction of adverse pathology generated from targeted (0.754), systematic (0.753), and combined approaches (0.763) were not significantly different (P = .831). ConclusionsThe validity of clinical risk prediction assessed with a multi-variable instrument was maintained in the setting of lesion-targeted biopsy.