Genomic Prostate Score, PI-RADSv2, and Progression in Men with Prostate Cancer on Active Surveillance

Abstract

PurposeOncotypeDx Genomic Prostate Score (GPS) is a 17-gene RNA expression assay intended to help guide treatment decisions for men diagnosed with prostate cancer. The Prostate Imaging-Reporting and Data System version 2 (PI-RADSv2) was developed to standardize the risk stratification of lesions identified on multiparametric prostate MRI. We sought to determine whether these tests are associated with increased risk of biopsy upgrade in men on active surveillance (AS). Materials and MethodsAll AS patients at University of California San Francisco (UCSF) were identified who had low/intermediate-risk PCa (PSA≤20, clinical stage T1/T2), Gleason Score (GS) 6 disease, underwent multiple biopsies, and had a GPS, mpMRI with PI-RADSv2 score, or both. The primary outcome was biopsy upgrade (an increase in GS from 3+3 to ≥ 3+4) analyzed by Cox proportional hazards regression. Results140 men had only a GPS test, 169 men had only PI-RADSv2 score, and 131 men had both tests. Each 5-unit increase in GPS was associated with increased risk of biopsy upgrade (Hazard ratio [HR]: 1.28; 95% confidence interval [CI]: [1.19, 1.39]; p<0.01). PI-RADS 5 vs. 1-2 (HR: 4.38; CI: [2.36, 8.16]; p<0.01) and 4 vs. PI-RADS 1-2 (HR: 2.62; CI [1.45, 4.76]; p<0.01) were also associated with increased risk of biopsy upgrade. In a sub-analysis of patients with both GPS and PI-RADSv2 scores, GPS was associated with biopsy upgrade, adding value to clinical covariates (partial likelihood ratio p=0.01). ConclusionsA higher GPS or PI-RADSv2 score of 4 or 5 is associated with increased risk of biopsy upgrade.