Validation of a genomic classifier to predict adverse pathology in men diagnosed with low risk prostate cancer.

71Background: The Decipher 22-feature genomic classifier (GC) has been validated to predict metastasis and prostate cancer specific mortality in needle biopsy (Bx) tissue of men with intermediate and high-risk prostate cancer. We validate GC in diagnostic Bx specimens for the prediction of high-grade/stage (HGS) disease at radical prostatectomy (RP) in men with low and favorable-intermediate (fav-int) NCCN risk group disease. Methods: We identified 176 men diagnosed with low or fav-int NCCN risk group disease who had available Bx GC scores and pathological information after RP from Cedars-Sinai, University of Calgary, Cleveland Clinic, MD Anderson, and Johns Hopkins. The GC score was calculated based on a locked random forest model. Scores range from 0-1 with cut points for GC low, intermediate and high risk groups as 0.6, respectively. The primary endpoint was HGS (Gleason group 3-5 or pT3b or lymph node invasion (LNI)). Univariable (UVA) and multivariable (MVA) logistic regression ...