Focal Salvage HDR Brachytherapy for Locally Recurrent Prostate Cancer in Patients Treated With Prior Radiotherapy

Inclusion Criteria: * Biopsy proven locally recurrent adenocarcinoma of the prostate after the completion of definitive radiation therapy for initially diagnosed prostate cancer. * Biopsy must be performed within 182 days of trial registration * Biopsy should be a standard sextant biopsy AND either a targeted MR/ultrasound guided biopsy or saturation biopsy or both. * Initial cancer diagnosis that fits these specific criteria: * Stages T1-T3a * Nx or N0 * Mx or M0 * Eligible initial definitive radiotherapy modalities include: * External beam radiotherapy, with photon or proton beam therapy * Conventional or moderately hypofractionated radiotherapy * Extremely hypofractionated external beam radiotherapy (Stereotactic body radiation therapy) * Definitive Brachytherapy: * Low-dose rate * High-dose rate * Locally recurrent disease confined to the prostate +/- seminal vesicles and immediately adjacent tissue, as evaluated by the following: * History/Physical examination * Radiographically node negative disease (N0), as defined by CT or MR of pelvis +/- abdomen within 6 months of registration. * No evidence of bone metastases (M0) on bone scan within 6 months of registration. * Fluciclovine-PET is encouraged, but not required * Patients receiving ADT are eligible as long as they meet the other eligibility criteria. However, the duration of all ADT must be documented. * Current ECOG Performance status Scale 0-2 * Current International Prostate Symptom Score (IPSS) \< 20 * The patient must be medically suitable to receive general anesthesia. * The patient must be able and willing to sign a study-specific written informed consent form before study entry. Exclusion Criteria: * Preregistration GI or GU toxicity (for any reason) grade ≥ 3 as defined in CTCAE version 4.03. That is, grade ≥ 3 GU or GI toxicity after first course of radiotherapy * Patients receiving any other investigational agents. * Uncontrolled inter-current illness including, but not limited to, ongoing or active infection, severely symptomatic congestive heart failure, cardiac arrhythmia, recent myocardial infarction in last 6 months, or psychiatric illness/social situations that could limit compliance with study requirements. * Patients who have received chemotherapy or immunotherapy within one month prior to study enrollment, other than ADT