The Diagnostic Yield of MRI-Transrectal US Fusion Prostate Biopsy in Patients With Suspected Prostate Cancer.

Abstract

Introduction: This study aimed to determine the positive predictive value (PPV) of magnetic resonance imaging-transrectal ultrasound (MRI-TRUS) machine fusion prostate biopsies, and to identify factors associated with a positive biopsy.

Methods: With ethics approval, we retrospectively evaluated all MRI-TRUS machine fusion prostate biopsies at our institution from September 2022 to April 2025. True positive clinically significant prostate cancers (csPCa) were defined as Gleason ≥7. PPVs were calculated overall and for PI-RADS 3, 4 and 5 categories. A generalized linear mixed model (GLMM) was created evaluating the following factors as fixed effects: PI-RADS category; prostate-specific antigen (PSA) density (<0.10, 0.10-0.15, ≥0.15 ng/mL²); lesion size (<7, 7-15, ≥15 mm); lesion location (peripheral vs transition zone); ultrasound correlate (present/absent); prostate size (<60 vs ≥60 mL); interval from MRI to biopsy (<6 months or not); and biopsy operator (2 radiologists). Referring urologist (n = 19) and reporting radiologist (n = 8) were included as random effects.

Results: 372 patients (mean age, 67 ± 7 years) with 529 lesions underwent biopsy. The overall PPV was 314/529 (59.4%). For PI-RADS 3 to 5, PPVs were 32/72 (44.4%), 123/243 (50.6%), and 159/214 (74.3%), respectively. In GLMM analysis, PI-RADS 5 versus 3 (OR 3.6, 95% CI, 1.7-7.4), PSA density ≥0.15 ng/mL² (OR 2.2, 95% CI, 1.2-3.8), and presence of an ultrasound correlate (OR 2.7, 95% CI, 1.7-4.2) were associated with true positive biopsies. Small lesion size <7 mm was associated with a false positive biopsy (OR 0.4, 95% CI, 0.2-0.8).

Conclusion: The yield of fusion prostate biopsies at our institution is high. PI-RADS 5, PSA density ≥0.15 ng/mL², and an ultrasound correlate at biopsy were associated with csPCa, whereas sub-7 mm lesions were negatively associated with csPCa.