Multiparametric Magnetic Resonance Imaging of the Prostate and Prostate-specific Membrane Positron Emission Tomography Prior to Prostate Biopsy (MP4 Study)

Background: Prostate-specific membrane antigen (PSMA) positron emission tomography/computerised tomography (PET/CT) is increasingly being utilised in the diagnostic pathway for prostate cancer (PCa). Recent publications have sug-gested that this might help identify those who can avoid biopsy.Objective: The primary objective of this study was to determine whether PET mag-netic resonance imaging (MRI) fusion could negate the need to biopsy prior to prostatectomy in a selected population of men.Design, setting, and participant: Multiparametric MRI (mpMRI) for PCa is our stan-dard of care prior to prostate biopsy. Biopsy-naive men with one or more Prostate Imaging Reporting and Data System (PI-RADS) 4 or 5 lesions >10 mm on mpMRI were invited to undergo PSMA PET/CT prior to biopsy. Following ethics approval, 60 men were recruited between September 2020 and March 2021. The key exclusion criteria included a previous history of PCa and previous prostate sur-gery or biopsy.Outcome measurements and statistical analysis: A positive PET MRI fusion scan was defined as "consistent with"as per the Memorial Sloan Kettering Cancer Center lexicon of certainty, and concordance with biopsy results was analysed. Clinically significant PCa (csPCa) was defined as grade group (GG) >= 2 on pathology. A chi-square analysis was performed with statistical significance defined at p < 0.05.Results and limitations: A total of 71 mpMRI lesions were positive on 61 (86%) PET MRI fusion scans. Fifty-nine of 61 lesions biopsied confirmed csPCa in 54 (92%). Of five of 59 lesions for which either biopsy was negative or low-grade cancer was found, three had rebiopsy of which two were confirmed to have csPCa corroborating with PET MRI fusion and one was reconfirmed to have GG1 only. For the remaining two, both had another lesion elsewhere in the gland confirming csPCa, and hence rebiopsy was not performed. Ultimately, 56 of 59 (95%) lesions with a positive PET MRI fusion scan were confirmed to have csPCa. All GG >3 can-cers had a positive PET MRI fusion scan. Conclusions: This prospective study of PET MRI fusion assessment of men with PI-RADS 4 or 5 lesion >10 mm on mpMRI confirms that the majority of men (95%) with a positive PET MRI fusion scan will have csPCa. This supports recently pub-lished retrospective data suggesting that selected men might avoid prostate biopsy prior to radical prostatectomy.Patient summary: In this research, we have confirmed that prostate-specific mem-brane antigen positron emission tomography/computerised tomography in combi-nation with magnetic resonance imaging could have an important role in enabling a diagnosis of prostate cancer. Using the combination of these scans, we could con-fidently predict the presence of aggressive prostate cancer in some men for which treatment is warranted. This means that there are some men who could possibility proceed directly to having prostate cancer surgery without the need for a confirma-tory prostate biopsy.(c) 2022 The Authors. Published by Elsevier B.V. on behalf of European Association of Urology. This is an open access article under the CC BY-NC-ND license (http://creative-commons.org/licenses/by-nc-nd/4.0/).