Title: Combining Prostate MRI and Micro-ultrasound to Omit Systematic Biopsy

Author: Dan Luca, Wayne G Brisbane

Area of Concentration (Petal): Basic, Clinical, & Translational Research

Specialty (if any): Urology, Urologic Oncology

Keywords: Prostate Cancer, Ultrasound, Prostate Biopsy

Background: 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 micro-ultrasound visualizes prostate cancers, enabling visual confirmation of target sampling.  We sought to evaluate if an MRI + micro-ultrasound targeted biopsy could omit systematic biopsy.

Objective: To evaluate if an MRI + micro-ultrasound 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, micro-ultrasound guidance, targeted and systematic biopsy. The MRI target was visualized with micro-ultrasound and biopsied.  We graded each region of interest (ROI) using PI-RADS and micro-ultrasound-based PRI-MUS scores. We considered cores containing Grade Group≥2 (GG≥2) as clinically significant prostate cancer (csPCa). 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.  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 one patient, with a dual imaging visible ROI, had GG≥2 detected on systematic biopsy but not in the ROI.  Otherwise, >97% of csPCa were detected with targeted biopsies alone.  In dual imaging visible ROIs, surgeons may consider omitting systematic biopsy.