PSMA PET/CT and PET/MRI in primary staging of prostate cancer and its effect on patient management

Purpose In the last decade, prostate specific membrane antigen (PSMA) positron emission tomography (PET) has gained its role as a novel tool in the primary staging of prostate cancer (PCa). This review focuses on the current knowledge on PSMA PET in primary PCa staging, which includes the Tumor-, Node-, Metastasis- (T-, N-, M-) staging, and the impact of PSMA PET on patient management. Methods A literature search was performed in all databases of Web of Science for peer-reviewed, original studies published in English until June 2022. The results were screened by abstract in the setting of primary staging of PCa, using PSMA PET tracers for imaging modalities PET/computed tomography (CT) and PET/magnetic resonance imaging (MRI). Results The available literature shows that PSMA PET is an accurate test in the primary staging of PCa. For T-staging, the combination of PSMA PET with the current gold standard multi-parametric MRI (mpMRI) may have a synergistic impact for assessment of tumor volume. For N- and M-staging, multiple studies show that PSMA PET clearly outperforms current conventional imaging modalities, which is also confirmed in the proPSMA randomized controlled trial that revealed a 27% higher accuracy of PSMA PET compared to conventional imaging. Several studies show that PSMA PET, due to its high accuracy, can lead to treatment adaption. Conclusions Despite the clear superiority of PSMA PET over conventional imaging for primary staging of intermediate- and high-risk PCa, PSMA PET is currently not yet identified as the gold standard imaging modality in this setting in the European Association of Urology (EAU) guidelines, given that no prospective studies demonstrating a clear benefit of treatment adaptation are available at this moment. The results of prospective trials exploring the benefit of PSMA PET-based treatment algorithms are, therefore, strongly awaited.