Micro-ultrasound for the detection of clinically significant prostate cancer in biopsy-naive men with negative MRI

Introduction: Despite a negative magnetic resonance imaging (MRI), some patients may still harbor clinically significant prostate cancer (csPCa, Gleason grade group ≥2). High-resolution micro-ultrasound (microUS) is a novel imaging technology that could visualize csPCa that is missed by MRI. Methods: This retrospective review included 1011 consecutive patients biopsied between September 2021 and July 2023 in Alberta, Canada. Among them were 103 biopsy-naive patients with negative MRI (Prostate Imaging Reporting & Data System [PI-RADS] ≤2) undergoing microUS-informed prostate biopsy (n=56) scored using Prostate Risk Identification Using Micro-ultrasound (PRI-MUS) or standard transrectal ultrasound prostate biopsy (n=47). The primary outcome was detection rate of csPCa stratified by biopsy technique and PRI-MUS score. Results: MicroUS biopsy identified csPCa in 14/56 (25%) compared to standard biopsy in 8/47 (17%) (p=0.33). Patients with lesions PRI-MUS ≥3 had csPCa detected at a higher rate compared to patients with PRI-MUS ≤2 (42% vs. 16%, p=0.03). The csPCa detection rate was significantly different comparing patients with PSA density <0.15 and PRI-MUS ≤2 compared to patients with PSA density ≥0.15 and PRI-MUS ≥3 (14% vs. 60%, p=0.02). Conclusions: MicroUS may aid in the detection of csPCa for patients with negative MRI.