Data from 6664 Prostate Cancer Prevention Trial placebo arm biopsies ( 5826 individuals ) , where prostate-specific antigen and digital rectal examination results were available within 1 year before the biopsy and PSA was 10 ng/mL , were used to develop a nominal logistic regression model to predict the risk of no vs low-grade ( Gleason grade < 7 ) vs high-grade cancer ( Gleason grade7 ) .