Detection of clinically significant prostate cancer by micro-ultrasound-informed systematic biopsy during MRI/micro-ultrasound fusion biopsy

Abstract

Introduction: High-resolution micro-ultrasound (microUS) is a novel imaging technique that may visualize clinically significant prostate cancer (csPCa), including those missed by magnetic resonance imaging (MRI), in real-time during prostate biopsy. Methods: From September 2021 to January 2022, 75 consecutive biopsy-naive men were entered into an observational cohort. All men underwent an MRI/microUS fusion prostate biopsy, completed by a single surgeon using the ExactVU device. At time of biopsy, each biopsy core was given a prostate risk identification using micro-ultrasound (PRI-MUS) score. Anonymized data were entered into a REDCap database. Cancer detection stratified by Prostate Imaging-Reporting & Data System (PI-RADS) and PRI-MUS score, and imaging modality was captured. Our primary outcome was the detection rate of csPCa in microUS-informed systematic biopsy cores, taken outside MRI-visible lesions, during MRI/microUS fusion prostate biopsy. Results: A median of three MRI-targeted and 12 microUS-informed systematic cores were taken per patient. MRI/microUS biopsy detected PCa in 84%, with csPCa detected in 52%. Of the 900 microUS-informed systematic cores, 105 cores were PRI-MUS ≥3 and 795 cores were PRI-MUS ≤2. csPCa was detected in 35% of the PRI-MUS ≥3 cores compared to 10% of the PRI-MUS ≤2 cores (p<0.0001). Detection of csPCa varied by core type: 8% of patients were diagnosed by MRI-targeted cores only, 38% were diagnosed by microUS-informed systematic cores only, and 54% were diagnosed by both. Conclusions: MicroUS-informed systematic biopsy may be a useful adjunct to MRI, with PRI-MUS ≥3 systematic cores having a 3.5-fold increased risk of csPCa compared to PRI-MUS ≤2 cores.