Comparison of 68Ga-labeled Prostate-specific Membrane Antigen Ligand Positron Emission Tomography/Magnetic Resonance Imaging and Positron Emission Tomography/Computed Tomography for Primary Staging of Prostate Cancer: A Systematic Review and Meta-analysis

Context: In December 2020, the US Food and Drug Administration approved a Ga-68-labeled prostate-specific membrane antigen ligand (Ga-68-PSMA-11) for posi-tron emission tomography (PET) in patients with suspected prostate cancer (PCa) metastasis who are candidates for initial definitive therapy. Ga-68-PSMA PET is increasingly performed for these patients and is usually combined with computed tomography (CT). In recent years, Ga-68-PSMA PET has been combined with high-resolution magnetic resonance imaging (MRI), which is beneficial for T staging and may further enhance the staging of primary PCa. Objective: To compare the diagnostic accuracy of Ga-68-PSMA PET/MRI with Ga-68-PSMA PET/CT for staging of primary PCa. Evidence acquisition: A comprehensive literature search was performed using Embase, PubMed/Medline, Web of Science, Cochrane Library, and Google Scholar up to June 24, 2021 in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Risk of bias was assessed using the QUA -DAS-2 tool. Evidence synthesis: The search identified 2632 articles, of which 27 were included. The diagnostic accuracy of Ga-68-PSMA PET/MRI, measured as the pooled natural logarithm of diagnostic odds ratio (lnDOR), was 2.27 (95% confidence interval [CI] 1.21-3.32) for detection of extracapsular extension (ECE), 3.50 (95% CI 2.14-4.86) for seminal vesicle invasion (SVI), and 4.73 (95% CI 2.93-6.52) for lymph node metastasis (LNM). For Ga-68-PSMA PET/CT, the analysis showed lnDOR of 2.45 (95% CI 0.75-4.14), 2.94 (95% CI 2.26-3.63), and 2.42 (95% CI 2.07-2.78) for detection of ECE, SVI, and LNM, respectively. The overall risk of bias and applicability concerns were assessed as moderate and low, respectively. Conclusions: Ga-68-PSMA PET/MRI shows high diagnostic accuracy equivalent to that of Ga-68-PSMA PET/CT for detection of ECE, SVI, and LNM in staging of PCa. There is an urgent need for direct comparison of the two diagnostic tests in future research. Patient summary: The use of radioactively labeled molecules that bind to prostate specific membrane antigen (Ga-68-PSMA) for positron emission tomography (PET) scans combined with either computed tomography (CT) or magnetic resonance imaging (MRI) is increasing for prostate cancer diagnosis. There is a need for direct comparison of the two tests to demonstrate the benefit of Ga-68-PSMA PET/MRI for determining tumor stage in prostate cancer. (C) 2021 The Authors. Published by Elsevier B.V. on behalf of European Association of Urology.