Metastatic prostate cancer patients eligible for 1st line hormonal treatment will undergo treatment with Enzalutamide (XTANDI). Subjects will receive 1dd 160 mg Enzalutamide orally continuously until progressive disease occurs. All subjects will undergo Choline (11C or 18F)-PET/CT scans at baseline, 2 weeks, 2 and 6, 9 and 12 months after starting androgen receptor (AR)-directed treatment. All subjects will undergo Whole Body MRI at baseline, 6, 9 and 12 months. Bone scans will be performed at baseline, 3 months, 6 and 12 months. PSA will be measured at baseline and every 4 weeks thereafter until at 12 months. CTC counts and characteristics will be measured at baseline and during Enzalutamide treatment.
