The primary objective of this study will be to evaluate the radiographic progression-free survival. We also want to determine the time to the start of second line systemic therapy, the prostate-cancer specific survival, the overall survival as well as to assess the quality of life, the toxicity and the PSA response. This study is the first randomized study in this setting and will employ a randomized phase II design to determine if a larger scale phase III trial is needed, thus the phase II/III design. The Phase II will consist of 130 CRPC patients with oligometastases, and the phase III will consist of the already randomized 130 patients plus an estimated 244 patients for a total sample size of 374 patients. This study will be conducted through the Genitourinary Radiation Oncology Group of Quebec (GROUQ) in different radiation oncology centres across Canada and the recruitment should be completed within 30 months of activation.