A 17-Gene Genomic Prostate Score Assay Provides Independent Information on Adverse Pathology in the Setting of Combined Multiparametric Magnetic Resonance Imaging Fusion Targeted and Systematic Prostate Biopsy

Abstract

Multiparametric magnetic resonance imaging and biopsy based molecular tests such as the 17-gene Oncotype DX® Genomic Prostate Score™ assay are increasingly performed to improve risk stratification in men with clinically localized prostate cancer. The prostate score assay was previously shown to be a significant independent predictor of adverse pathology findings at radical prostatectomy in men diagnosed by systematic biopsies only. Therefore, we investigated the ability of the prostate score assay to predict adverse pathology findings in the setting of magnetic resonance imaging guided prostate biopsy. We identified men diagnosed with NCCN® (National Comprehensive Cancer Network®) very low, low or intermediate risk prostate cancer who underwent simultaneous multiparametric magnetic resonance imaging fusion targeted and systematic prostate biopsy with subsequent radical prostatectomy within 6 months. Prostate score assay testing was performed on biopsy tissue with the highest Gleason score. The primary outcome of the study was adverse pathology findings, defined as Gleason score 4 + 3 or greater disease and/or pT3+ at radical prostatectomy. Independent predictors of adverse pathology findings were determined in a multivariable model to adjust for clinical parameters. A total of 134 men were eligible for primary analysis. On univariable analysis the UCLA score, magnetic resonance imaging, prostate score assay results and biopsy Gleason score were significant predictors of adverse pathology findings. After multivariable adjustment prostate score assay values remained a significant predictor of adverse pathology results (prostate score assay per 20 U OR 3.28, 95% CI 1.74-6.62, p <0.001). A wide and overlapping distribution of prostate score assay results was seen across PI-RADS® (Prostate Imaging Reporting and Data System) version 2 scores. The prostate score assay result is an independent predictor of adverse pathology findings in patients who were diagnosed with very low, low or intermediate risk prostate cancer in the setting of multiparametric magnetic resonance imaging fusion prostate biopsy. This assay can be useful as an independent technology or an adjunct technology to multiparametric magnetic resonance imaging to individualize risk stratification of low and intermediate risk prostate cancer.