Fractionated Stereotactic Radiotherapy Plus Second-generation Antiandrogen for Oligometastatic Castration-resistant Prostate Cancer Patients.

Inclusion Criteria: * Patients with histologically prostate adenocarcinoma, confirmed with a biopsy. * Testosterone in biochemical castration ranges (testosterone \<50 ng/ml or 1.7 nmol/L) and documented progression: biochemical according to Phoenix criteria or distant by radiological confirmation (PSMA PET/CT or Choline PET/CT) * Biochemistry progression confirmed according to Phoenix criteria, with testosterone in castration levels (testosterone \<50 ng/ml or 1.7 nmol/L). * Radiological confirmation (with choline-PET/CT or 68Ga-PSMA-PET/CT) of ≤5 node or bone metastasis, non-visceral, eligible to receive SBRT treatment (\< 3 cm major diameter in bone metastases, \< 5 cm in lymph node metastases). In the case of very close metastases, a limit of up to 5 treatment fields with SBRT is allowed, instead of 5 metastases. * Patients candidate to receive treatment with abiraterone or enzalutamide as per clinical routine, and treatment selection and prescription assigned by responsible physician before the inclusion in the study. or or who has started treatment no more than 14 days prior to signing, as first-line treatment after a diagnosis of oligoresistance. * Patients must provide written informed consent. * Life expectancy \> 3 months. Exclusion Criteria: * Patients with prostate carcinoma with histology other than adenocarcinoma. * No previous biopsy. * \> 5 metastasis, not approachables in 5 treatment fields * Patients with visceral metastasis and or metastasis non elegible to receive SBRT. * Patients with Testosterone above castration levels * Patients with prior treatment with docetaxel as first-line CRPC treatment (previous docetaxel treatment is permitted when administered as hormone-sensitive metastatic prostate cancer treatment.