5500/20 vs. SABR or Brachytherapy for PRimary OligoMetastatic Prostate Cancer Treatment (PROMPT)

Inclusion Criteria: * Signed study specific informed consent * European Cooperative Oncology Group performance status 0 to 2 * Histologically confirmed adenocarcinoma of the prostate * Any Tumor stage, any T, any N, M1 * No prior therapy for prostate cancer apart from androgen deprivation * Planned for long-term androgen deprivation therapy (greater than 9 months in duration) * Patient is able and willing to complete the quality of life questionnaires, and other assessments that are a part of this study * For brachytherapy arms, patient must be technically suitable for brachytherapy according to investigator, in terms of bladder function and prostate size. Exclusion Criteria: * High metastatic burden defined as 5 or more bone metastases or visceral metastases * Contraindications to EBRT such as active inflammatory bowel disease or previous pelvic radiation * For Brachytherapy Arms =: Any prior Transurethral resection of prostate