To evaluate prognostic markers, prostate-specific antigen, prostate health index (PHI), and prostate volume indexed measures (prostate-specific antigen density and prostate health index density) for predicting positive prostate cancer biopsies in magnetic resonance (MR) transrectal ultrasound fused versus nonfused transrectal ultrasonography biopsy.

A retrospective cohort of 211 patients that had at least 1 suspected MR lesion, Prostate Imaging-Reporting and Data System ≥3, and subsequent biopsy (2015-2017). Clinical characteristics and prognostic biomarkers were evaluated as predictors of prostate cancer detection by type of biopsy guidance (fused vs nonfused).

One-hundred twenty-one patients had nonfused and 90 had fused biopsies. PHI and PHID had greater area under the receiver operating characteristics curve (AUC) in predicting positive biopsies than prostate-specific antigen or PSAD for both nonfused and fused biopsy. PHI 0.78 (95% CI 0.67-0.88) and PHID 0.82 (95% CI 0.73-0.91) had the greatest AUC for predicting biopsy results for nonfused and fused biopsies, respectively. Multiple-variable models did not improve model fit compared to single variables. Based on Youden's index, a cut-off value of 45.9 for PHI in nonfused and 0.64 for PHID in fused biopsies would reduce the number of negative biopsies by 77.3% and 63.4%, respectively, but the percentage of missed clinically significant cancer biopsies would be 19% and 12%, respectively.

Our findings demonstrate that the choice of prognostic biomarkers for predicting positive biopsies is a function of the biopsy guidance method. Volume indexed derivatives appear to have greater value when a MRI-US fused method is used.