Prostate Mapping for Cancer Diagnosis: The Madrid Protocol. Transperineal Prostate Biopsies Using Multiparametric Magnetic Resonance Imaging Fusion and Micro-Ultrasound Guided Biopsies

Abstract

Purpose: We assessed the prostate cancer detection accuracy of transperineal prostate biopsy using multiparametric magnetic resonance imaging/ultrasound fusion targeted biopsy and micro-ultrasound during the same procedure. Micro-ultrasound is a new high-resolution imaging system that allows real-time targeted biopsy.

Materials and methods: A total of 194 consecutive patients underwent transperineal prostate biopsies using real-time targeted micro-ultrasound (ExactVu™) and ultrasound fusion targeted biopsy (BiopSee®) in the same procedure, from February 2018 to September 2019. Biopsies were performed using a transperineal needle guide attached to the 29 MHz high-resolution micro-ultrasound transducer.

Results: The overall positive rate was 56% (108) for prostate cancer and 42% (81) for clinically significant prostate cancer (Gleason Grade Group greater than 1), and adding micro-ultrasound and magnetic resonance imaging detected significantly more clinically significant prostate cancer than systematic biopsy (p <0.001). Micro-ultrasound found 12 of 108 (11%) prostate cancers that were missed by all other techniques and 11 (92%) were clinically significant prostate cancer. PI-RADS® and PRI-MUS™ (Prostate Risk Identification Using Micro-Ultrasound) were strong predictors of clinically significant prostate cancer in a logistic regression model (AUC 0.76). For prostate specific antigen greater than 4 ng/ml, PI-RADS greater than 3, there was an improvement in detection rate between PRI-MUS 4 and PRI-MUS 5 (52% Gleason Grade Group greater than 1 to 92% Gleason Grade Group greater than 1). No fever or clinical infection was observed and 17 (8.7%) patients presented with minor complications (Clavien Dindo I).

Conclusions: This is the first study using a transperineal approach for micro-ultrasound guided biopsy and multiparametric magnetic resonance imaging fusion biopsy. The results show a high accuracy for prostate cancer and clinically significant prostate cancer diagnosis, without infectious complications. The proposed method should be validated in large randomized clinical trials.

Keywords: biopsy; multiparametric magnetic resonance imaging; prostatic neoplasms; ultrasonography.