Comparison of the Diagnostic Accuracy of Micro-ultrasound and Magnetic Resonance Imaging/Ultrasound Fusion Targeted Biopsies for the Diagnosis of Clinically Significant Prostate Cancer

Abstract

Multiparametric magnetic resonance imaging (mpMRI) and MRI/ultrasound (US) fusion targeted biopsies are an increasingly popular alternative to randomized biopsies, but adoption of this technique has been limited owing to its additional costs and complexity. High-resolution micro-ultrasound (micro-US) is a real-time US-based imaging modality that allows real-time targeted prostate biopsies using the Prostate Risk Identification Using Micro-Ultrasound risk identification protocol. We compared the diagnostic accuracy of micro-US targeted biopsies (index test) and MRI/US fusion targeted biopsies (reference standard test) in detecting clinically significant prostate cancer (csPC), defined as Gleason ≥7 disease, in a prospectively collected cohort of 104 patients with suspected PC defined according to prostate-specific antigen, digital rectal examination, and the presence of at least one Prostate Imaging-Reporting and Data System ≥3 lesion at mpMRI. PC was diagnosed in 56 patients (54%) and csPC in 35 (34%). Micro-US sensitivity for csPC detection was 94%, with 33/35 csPC cases correctly identified. The negative predictive value was 90%, while the positive predictive value was 40% and the specificity was 28%. Of the 61 targeted zones concordant between micro-US and mpMRI, 24 were csPC. Discordant targeted lesions led to csPC discovery by micro-US in three cases and mpMRI in four cases. Both techniques missed one case for which csPC was diagnosed by systematic biopsies only. PATIENT SUMMARY: According to the results of our preliminary trial, micro-ultrasound may provide additional information regarding the presence or absence of clinically significant prostate cancer (PC) in patients with suspected PC. Further studies are warranted to investigate how this new imaging modality can best be leveraged within the PC diagnostic pathway.

Keywords: Diagnosis; Micro-ultrasound; Multiparametric magnetic resonance imaging; Prostate biopsy; Prostate cancer.