To validate the 17-gene Oncotype DX Genomic Prostate Score® (GPSTM) biopsy-based gene expression assay as a predictor of adverse pathology (AP, Gleason score [pGS] ≥ 4+3 and/or ≥ pT3) in a prospectively enrolled cohort.
Between July 2014 and September 2015, 1,200 men with very low-, low-, and favorable intermediate-risk prostate cancer enrolled in a multi-institutional prospective study of the GPS assay (NCT03502213). The subset who proceeded to immediate radical prostatectomy (RP) after GPS testing was included in a pre-specified sub-analysis of GPS on biopsy and its association with surgical AP on RP using logistic regression and receiver operating characteristic (ROC) curves. The effect of GPS testing on physicians' and patients' attitudes about decision making was assessed with the Decisional Conflict Scale (DCS).
114 patients (treated by 59 physicians from 19 sites) elected RP and 40 (35%) had AP. GPS result was a significant predictor of AP (odds ratio per 20 GPS units [OR/20 units]: 2.2; 95% CI 1.2-4.1; p=0.008) in univariable analysis and remained significant after adjustment for biopsy Gleason score, clinical T-stage, and logPSA (OR/20 units: 1.9; 95% CI 1.0-3.8; p=0.04), or NCCN risk group (OR/20 units: 2.0; 95% CI 1.1-3.7; p=0.02). Mean pre-GPS DCS score was 27 (95% CI 24 to 31), which improved significantly after GPS testing to 14 (95% CI 11 to 17) (p<0.001).
In this real-world multi-institutional study, the GPS assay was prospectively confirmed as an independent predictor of AP at surgery. GPS testing was associated with reduced patient decisional conflict.
Urology. 2019 Jan 03 [Epub ahead of print]
Scott Eggener, Lawrence I Karsh, Tim Richardson, Alan W Shindel, Ruixiao Lu, Steven Rosenberg, Evan Goldfischer, Howard Korman, John Bennett, Jay Newmark, Bela S Denes
University of Chicago, Chicago, IL. Electronic address: ., The Urology Center of Colorado, Denver, CO. Electronic address: ., Wichita Urology, Wichita, KS. Electronic address: ., University of California, San Francisco, CA. Electronic address: ., Genomic Health, Inc., 101 Galveston Drive, Redwood City, CA 94063. Electronic address: ., The Iowa Clinic, West Des Moine, IA. Electronic address: ., Premier Medical Group of the Hudson Valley, Poughkeepsie, NY. Electronic address: ., Comprehensive Urology, Royal OAK, MI. Electronic address: ., Genomic Health, Inc., 101 Galveston Drive, Redwood City, CA 94063. Electronic address: ., Genomic Health, Inc., 101 Galveston Drive, Redwood City, CA 94063. Electronic address: ., Blue Earth Diagnostics, Inc., Burlington, MA. Electronic address: .