Evolution of Targeted Prostate Biopsy by Adding Micro-Ultrasound to the Magnetic Resonance Imaging Pathway

Abstract

Background: Although multiparametric magnetic resonance imaging (mpMRI) revolutionized the implementation of prostate biopsies, a considerable amount of clinically significant prostate cancer (csPCa) is missed when performing mpMRI-targeted biopsies only. Microultrasound (micro-US) is a new modality that allows real-time targeting of suspicious regions.

Objective: To evaluate micro-US of the prostate with real-time targeting of suspicious regions in patients suspected to have prostate cancer (PCa).

Design, setting, and participants: We examined 159 patients with prior mpMRI and suspicion of PCa with micro-US in the period from February to December 2018. Micro-US lesions were documented according to the prostate risk identification for micro-US (PRI-MUS) protocol, and were blinded to the mpMRI results and targeted independently of the mpMRI lesions.

Outcome measurements and statistical analysis: The main outcomes were cancer detection rate, additional detection of csPCa, and International Society of Urological Pathology (ISUP) grade group upgrading via micro-US.

Results and limitations: PCa was found in 113/159 (71%) men, with 49% (78/159) having clinically significant cancer (csPCa; ISUP ≥ 2). Micro-US-targeted biopsies resulted in a higher ISUP grade group than the nontargeted biopsies in 26% (42/159), compared with both nontargeted and MRI-targeted biopsies in 16% (26/159). In 17% (27/159) of patients, targeted mpMRI-guided biopsy was negative with cancer identified in the micro-US-guided biopsy, of whom 20 had csPCa. The comparison with only MRI-positive patients is the main limitation of this analysis.

Conclusions: Our data show an added benefit of micro-US in addition to mpMRI-targeted biopsies in a population of men at risk of PCa. A novel biopsy protocol with solely targeted biopsy with micro-US and mpMRI seems possible, replacing conventional ultrasound and omitting standard systematic biopsies.

Patient summary: In this report, we looked at the performance of microultrasound in the setting of diagnosing prostate cancer. We found that microultrasound is a good addition to magnetic resonance imaging (MRI) of the prostate and presents an alternative for men who may not undergo MRI.

Keywords: Microultrasound; Multiparametric magnetic resonance imaging; Prostate biopsy; Prostate cancer; Target biopsy.