Prostate SBRT for Locally Recurrent Prostate Cancer After Prior Radiotherapy

Background: * Prostate cancer that recurs after prior radiation treatment can be challenging to cure due to the side effects of available treatments such as surgery and cryoablation. * Re-irradiation with brachytherapy or stereotactic approaches has shown excellent rates of prostate cancer disease control with tolerable side effects. * Using image guidance to allow highly conformal focal re-irradiation may potentially increase the efficacy of re-irradiation. Objectives: -Define the maximum tolerated dose (MTD) of image guided, focally dose escalated prostate radiation with stereotactic body radiation therapy (SBRT) in patients with a local recurrence of prostate cancer after prior radiotherapy. Eligibility: * Histological confirmation of recurrent prostate cancer after prior irradiation (external beam or brachytherapy) * No evidence of distant metastases of prostate cancer * No prior prostatectomy * Subject is greater than or equal to18 years old * Eastern Cooperative Oncology Group (ECOG) performance status less than or equal to 2 (Karnofsky greater than or equal to 60%). Design: * This is a Phase I trial of focal dose escalation with SBRT using image and pathologic guidance. * Areas in the prostate shown to have tumor on biopsy or with advanced imaging studies will be treated with highly conformal SBRT over a period of two to three weeks. Treatment will be guided and gated by fiducials implanted in the prostate. * Patients will be treated to escalating doses based on tolerability of the treatment. * Quality of life and functional outcomes such as urine, bowel, and erectile function will be assessed with questionnaires. * Up to 52 patients will be enrolled.