Combining Prostate MRI and Microultrasound to Omit Systematic Biopsy

Purpose: The diagnosis of prostate cancer often includes MRI-guided biopsy. Many surgeons perform targeted and systematic biopsies to compensate for registration errors between MRI and conventional ultrasound (5-7 mHz). Using 29 mHz, microultrasound visualizes prostate cancers, enabling visual confirmation of target sampling. We sought to evaluate whether an MRI + microultrasound targeted biopsy could omit systematic biopsy. Methods: We retrospectively evaluated 155 men undergoing transperineal prostate biopsy at the University of Florida. Eighty-three men met inclusion criteria: MRI prior, microultrasound guidance, and targeted and systematic biopsy. The MRI target was visualized with microultrasound and biopsied. We graded each region of interest (ROI) using Prostate Imaging Reporting & Data System (PI-RADS) and Prostate Risk Identification using Micro-Ultrasound (PRI-MUS) scores. We considered cores containing Grade Group ≥ 2 (GG ≥ 2) as clinically significant prostate cancer. The primary endpoint was the GG ≥ 2 cancer detection rate (CDR = GG ≥ 2 targeted cores/GG ≥ 2 all cores). Results: Patients with PI-RADS and PRI-MUS scores ≥ 3 had a targeted-only CDR of 93.3%. Those with scores ≥ 4 (dual imaging visible) had a CDR of 97.4%. Systematic without targeted cores had CDR of 61.5%. One patient (1.2%) had GG ≥ 2 detected on systematic biopsy alone. Area under the curve (AUC) values for PI-RADS, PRI-MUS, and dual imaging visible lesions were 0.73, 0.69, and 0.73, respectively ( P = NS). Conclusions: Only 1 patient, with a dual imaging visible ROI, had GG ≥ 2 detected on systematic biopsy but not in the ROI. Otherwise, > 97% of clinically significant prostate cancer were detected with targeted biopsies alone. In dual imaging visible ROIs, surgeons may consider omitting systematic biopsy.