Radioligand Therapy After PSMA PET Guided External Beam Radiotherapy for Treating Post-Prostatectomy Patients With Biochemically Recurrent Prostate Cancer

This phase I trial tests the safety, side effects and best dose of radioligand therapy (lutetium Lu 177 PSMA-10.1 \[177Lu-rhPSMA-10.1\]) after prostate specific membrane antigen (PSMA) positron emission tomography (PET)-guided external beam radiotherapy in treating post-prostatectomy patients with prostate cancer that has come back after a period of improvement (recurrent). In this study, radioligand therapy is a radioactive drug called 177Lu-rhPSMA-10.1. It works by binding to PSMA-expressing prostate tumor cells and delivering the radioactive portion of the drug directly to the tumor cells while not harming normal cells. Radiation therapy such as external beam radiotherapy uses high energy x-rays to kill tumor cells and shrink tumors. Giving radioligand therapy with PSMA PET-guided external beam radiotherapy may kill more tumor cells in post-prostatectomy patients with biochemically recurrent prostate cancer.