Multicenter Randomized Trial of 68Ga-PSMA-11 PET/CT Based SRT After Radical Prostatectomy

This phase III trial studies how well Gallium Ga 68-labeled PSMA-11 (68Ga-PSMA-11) positron emission tomography (PET)/computed tomography (CT) works in diagnosing participants with prostate cancer that has come back after surgery. 68Ga-PSMA-11 are taken up by cancer cells. Diagnostic procedures, such as PET/CT scans, may help find and diagnose prostate cancer and find out how far the disease has spread. Giving 68Ga-PSMA-11 with PET/CT may help doctors plan better for salvage radiation therapy in participants with recurrent prostate cancer.

PRIMARY OBJECTIVE: I. Success rate of salvage radiation therapy (SRT) measured as biochemical progression-free survival after initiation of SRT. SECONDARY OBJECTIVES: I. Sub-group analysis of the primary endpoint (success rate of SRT) within the subgroup with baseline PSA ≥ 0.5 ng/ml II. 5-year biochemical progression-free survival rate (from date of randomization). III. Metastasis free survival. IV. Initiation of additional salvage therapy after completion of SRT. V. Change in initial treatment intent. OUTLINE: Participants are randomized to 1 of 2 arms. ARM I: Participants receive standard of care SRT. ARM II: Participants receive 68Ga-PSMA-11 intravenously (IV) and 50-100 minutes later undergo whole-body (skull base to mid-thighs) PET/CT. Participants then undergo SRT per the discretion of the treating radiation oncologist. After conclusion of PET/CT, participants are followed up periodically for up to 5 years.