Detection of clinically significant prostate cancer by micro-ultrasound-informed systematic biopsy during MRI/micro-ultrasound fusion biopsy.

original research Detection of clinically significant prostate cancer by micro-ultrasound-informed systematic biopsy during MRI/ micro-ultrasound fusion biopsy Betty Wang1, Stacey Broomfield1, Anaïs Medina Martín2, Patrick Albers1, Christopher Fung3, Adam Kinnaird1,2,4,5,6 Division of Urology, Department of Surgery, University of Alberta, Edmonton, AB, Canada; 2Alberta Prostate Cancer Research Initiative (APCaRI), Edmonton, AB, Canada; 3Department of Radiology & Diagnostic Imaging, University of Alberta, Edmonton, AB, Canada; 4Cancer Research Institute of Northern Alberta (CRINA), Edmonton, AB, Canada; 5 Alberta Centre for Urologic Research and Excellence (ACURE), Edmonton, AB, Canada; 6Department of Oncology, University of Alberta, Edmonton, AB, Canada 1 Cite as: Wang B, Broomfield S, Medina Martín A, et al. Detection of clinically significant prostate cancer by microultrasound-informed systematic biopsy during MRI/micro-ultrasound fusion biopsy. Can Urol Assoc J 2023;17(4):117-20. http://dx.doi.org/10.5489/cuaj.8094 Published online December 6, 2022 Appendix available at cuaj.ca ABSTRACT INTRODUCTION: High-resolution micro-ultrasound (microUS) is a novel imaging technique that may visualize clinically significant prostate cancer (csPCa), including those missed by magnetic resonance imaging (MRI), in real time during prostate biopsy. METHODS: From September 2021 to January 2022, 75 consecutive biopsy-naive men were entered into an observational cohort. All men underwent an MRI/microUS fusion prostate biopsy, completed by a single surgeon using the ExactVU device. At time of biopsy, each biopsy core was given a Prostate Risk Identification using MicroUS (PRI-MUS) score. Anonymized data were entered into a REDCap database. Cancer detection stratified by Prostate Imaging-Reporting & Data System (PI-RADS) and PRI-MUS score, and imaging modality was captured. Our primary outcome was the detection rate of csPCa in microUSinformed systematic biopsy cores, taken outside MRI-visible lesions, during MRI/microUS fusion prostate biopsy. RESULTS: A median of three MRI-targeted and 12 microUS-informed systematic cores were taken per patient. MRI/microUS biopsy detected PCa in 84%, with csPCa detected in 52%. Of the 900 microUS-informed systematic cores, 105 cores were PRI-MUS ≥3 and 795 cores were PRI-MUS ≤2. csPCa was detected in 35% of the PRI-MUS ≥3 cores compared to 10% of the PRI-MUS ≤2 cores (p<0.0001). Detection of csPCa varied by core type: 8% of patients were diagnosed by MRI-targeted cores only, 38% were diagnosed by microUSinformed systematic cores only, and 54% were diagnosed by both. CONCLUSIONS: MicroUS-informed systematic biopsy may be a useful adjunct to MRI, with PRI-MUS ≥3 systematic cores having a 3.5-fold increased risk of csPCa compared to PRI-MUS ≤2 cores. INTRODUCTION New imaging technologies have improved our ability to detect clinically significant prostate cancer (csPCa, defined as Gleason grade group ≥2). Magnetic resonance imaging (MRI)guided prostate biopsy has become standard-of-care in many countries, however, it fails to detect up to 25% of csPCa, which are invisible on MRI, and thus systematic biopsy is still required.1-3 High-resolution microultrasound (microUS) is an imaging technique that may visualize csPCa (potentially including some missed by MRI) in real time during biopsy.4 Therefore, combined MRI/microUSguided fusion prostate biopsy may be a novel technique used to increase detection of csPCa. The objective of our study was to determine the detection rate of csPCa during microUS-informed systematic biopsy when used in combination with MRIguided biopsy for biopsy-naive men. METHODS All biopsy-naive men undergoing combined MRI/microUS-guided fusion prostate biopsy at the University of Alberta between September 2021 and January 2022 were entered into an observational cohort. Patients were internally referred from a high-volume tertiary urology center for fusion prostate biopsy, with high clinical suspicion of localized prostate cancer. Human research ethics board approval was obtained (HREBA.CC-21-0388). Subjects underwent an MRI/ microUS device fusion (FusionVu) CUAJ • april 2023 • Volume 17, Issue 4 © 2023 Canadian Urological Association 117 Wang et al Key messages Despite it gaining popularity, MRI alone can still miss up to 25% of csPCa. █ High-resolution microUS is a novel imaging technique that may visualize csPCa missed by MRI in real time during prostate biopsies. █ MRI/microUS fusion biopsy detected any prostate cancer in 84%, with a csPCa detection rate of 52%. █ MicroUS-informed systematic biopsy cores with a PRI-MUS 5 score had an overall cancer detection rate of 84%, with a csPCa rate of 57%. █ PRI-MUS ≥3 systematic cores have a 3.5-fold increased risk of csPCa compared to PRI-MUS ≤2 cores. █ transrectal prostate biopsy using the ExactVU MRI/ microUS fusion device (Exact Imaging, Toronto, Canada). All biopsies were performed by a single surgeon, with a high-volume practice in focal therapy for prostate cancer and four years’ experience performing transrectal ultrasound (TRUS) prostate biopsy. Prior to biopsy, a multiparametric prostate MRI (mpMRI) was completed, and all relevant lesions were assigned a Prostate Imaging Reporting & Data System version 2.1 (PI-RADS) score. The surgeon was not blinded to results of the mpMRI prior to the biopsy procedure. At time of biopsy, each biopsy core was given a Prostate Risk Identification using Micro-Ultrasound (PRI-MUS) score.5 If the patient had a PI-RADS ≥3 lesion(s) on MRI, then three MRItargeted cores were first obtained per lesion, followed by microUS-informed systematic biopsy (12 cores). If a suspicious PRI-MUS lesion was identified as part of the systematic biopsy, the surgeon may alter his biopsy angle to preferentially target that lesion; however, only a single core is taken per lesion as part of the sextant template systematic biopsy. During the MRI-targeted biopsy, if the lesion also happens to have a high PRI-MUS score, only three cores would be taken, but the cores would be labeled with both the MRI-reported PI-RADS score, as well as the surgeon-assigned PRI-MUS score. The primary outcome was the detection rate of csPCa in microUS-scored systematic biopsy cores taken 118 CUAJ • april 2023 • Volume 17, Issue 4 outside the MRI-visible regions of interest. Secondary outcomes included overall and csPCa detection rates stratified by PI-RADS and PRI-MUS scores, as well as cancer detection rate in targeted biopsy cores, also stratified by PRI-MUS score. Fisher’s exact test was used to compare csPCa detection in systematic cores stratified by PRI-MUS scores (<3 vs. ≥3). A two-sided p-value of <0.05 was considered significant. RESULTS A total of 900 microUS-informed systematic cores were obtained from 75 consecutive men undergoing MRI/ microUS fusion prostate biopsy (Table 1). A median of three (interquartile range [IQR] 3–3) targeted cores were Table 1. Baseline pat (...truncated)