Prostate SBRT for Locally Recurrent Prostate Cancer After Prior Radiotherapy

Background: Prostate cancer is the second leading cause of cancer death in United States (U.S.) men. Radiation is an effective treatment for most patients with localized prostate cancer, but sometimes the tumor returns. Researchers want to see if a highly focused type of radiation can help. It is given in only 5 treatments. It is called stereotactic body radiation therapy (SBRT). Objective: To study the maximum tolerated dose and side effects of stereotactic body radiation therapy in people with a local recurrence of prostate cancer after radiation. Eligibility: Men at least 18 years old who have recurrent prostate cancer after radiation therapy and no evidence of distant metastatic disease. Design: Participants will be screened with blood tests, physical exam, and medical history. They may also have: Magnetic resonance imaging (MRI) scan of the prostate. Positron emission tomography (PET)/computed tomography (CT) scan. Participants will get an injection of 2-(3-{1-carboxy-5-\[(6-18F-fluoro-pyridine-3-carbonyl)-amino\]-pentyl}-ureido)-pentanedioic acid (18F-DCFPyL) for the PET scan. They will lie very still on their back on the scanner table. Small samples of prostate tumor tissue will be taken by a needle through the skin or rectum to see if the cancer is in the prostate. Small metal seeds will be placed into the prostate at the same time to help guide the radiation. About 2 weeks later, participants will have a radiation treatment planning CT scan. Participants will answer questions about their urine function, bowel function, erectile function, and mood. Participants will receive SBRT. They will have 5 radiation treatments over 2 weeks. Participants will have follow-up visits. They will have a physical exam, blood tests, and questionnaires. Six months after ending SBRT, the 18F-DCFPyL PET/CT will be repeated. Participants will continue to have routine visits until two years after treatment is completed....