Is there a role of PSMA-PET in focal therapy planning and follow-up?

INTRODUCTION: Focal therapy (FT) is a promising alternative to radical treatments for localized Prostate Cancer (PCa) in selected patients. However, it is not yet considered a standard treatment option, and there is currently no consensus on managing patients after FT. In this context, Prostate-Specific Membrane Antigen Positron Emission Tomography (PSMA-PET) may support multiparametric MRI (mpMRI) for both pre-operative planning and follow-up. The aim of this systematic review was to provide a comprehensive overview of the current applications of PSMA-PET in the field of FT and to analyze its future perspectives. EVIDENCE ACQUISITION: A literature search was performed using PubMed and Scopus databases, following the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) statement recommendations. All studies reporting data on PSMA-PET performed before and/or after FT for PCa were included. A narrative synthesis was employed to summarize the review findings. No quantitative synthesis was performed due to the heterogeneity and limitations of the studies. EVIDENCE SYNTHESIS: Seven studies (2 case reports, 1 retrospective, and 4 prospective single-center studies) were included in this review. A moderate-severe risk of bias was assessed for the included studies. In the field of FT, PSMA-PET showed promising but yet not validated results with several possible applications: (1) pre-operative planning and staging, aiming to improve patient selection trough the identification of intraprostatic suspected lesions and more accurate local and systemic staging; (2) guidance for biopsy and Region of Interest (ROI) definition; (3) follow-up imaging tool, aiming to decrease the number of unnecessary surveillance biopsies. CONCLUSIONS: Limited evidence exists regarding the use of PSMA-PET in the field of FT, considering pre-operative setting, treatment guidance and its use as a non-invasive tool to evaluate treatment success or failure and for follow-up. In this scenario, even if the current evidence is still limited and inconclusive, PSMA-PET showed promising results with several possible applications.