PSMA PET/CT and radiotherapy in prostate cancer: a winning team

Purpose Radiotherapy (RT) represents an extremely effective therapeutic approach in the treatment of prostate cancer both in the primary stage and in patients with biochemical relapse (BCR) after radical therapy. In particular, the possibility of using targeted treatments on individual lesions is associated with the need for extremely accurate imaging methods that are able to accurately identify the disease sites. In this perspective, the recent development of 68 Ga-PSMA PET radiotracer which binds to prostate-specific membrane antigen ([ 68 Ga]Ga-PSMA-11), a transmembrane glycoprotein overexpressed in PCa cells, has ensured greater diagnostic efficacy, compared to conventional imaging techniques. The purpose of this review was to analyze the usefulness and role of [ 68 Ga]Ga-PSMA-11 in the correct management of the patient to undergo radiotherapy. Materials and methods We performed a comprehensive literature review for published studies for planned, ongoing and completed clinical trials, based on Pubmed/Medline, Scopus, Web of Science, Cochrane Library, Google Scholar, and the Embase databases until June 2021. This search was carried on using the following search string: (‘PSMA’ OR ‘ 68 Ga-PSMA-11’) AND ('pet'/exp OR 'pet' OR 'positron emission tomography') AND (‘prostate cancer/exp’ OR ‘prostate cancer’ OR ‘radiotherapy/exp OR radiotherapy’). We presented evolving evidence in the radiation treatment and in defining treatment paradigm in patients with prostate cancer and emerging evidence in [ 68 Ga]Ga-PSMA-11PET/CT changing targeted radiotherapy treatment. We presented an overview of the most recent studies in the different stages of the disease (staging/BCR/m-CRPC). Results The studies analyzed showed that [ 68 Ga]Ga-PSMA-11 allows an accurate localization of the disease sites, significantly impacting the management of radiotherapy treatments both in the primary therapy phase and in the identification of relapse sites or in the assessment of extension. Metastatic, with a significant change in patient management. In particular, [ 68 Ga]Ga-PSMA-11 PET/CT has increased the correct identification of oligometastatic patients who can undergo radiotherapy treatments targeted on individual lesions, significantly delaying the start of systemic therapy, often accompanied by comorbidities. Conclusion [ 68 Ga]Ga-PSMA-11 PET/CT appears to be a useful method for guiding radiation therapy in patients with prostate cancer at all stages of the disease.