F-choline PET in Early Response Assessment for Castration Resistant Prostatic Cancer

Until today no current diagnostic tool exists to identify an early objective response when patients with castration-resistant prostate cancer were treated by abiraterone acetate or enzalutamide. According to the Prostate Cancer Working Group, the investigators have to wait 12 weeks before the first evaluation. To know soon that the treatment is effective will be decisive for the oncologist, even more in palliative situation where second effects can't be imposed to patients. In post-docetaxel, the F-choline PET-CT could be used to assess the response of this new therapy. Moreover, the investigators suppose that we can assess an early stage if there is an objective therapeutic response, at 6 weeks of treatment, in order to avoid unnecessarily and expansive treatment. The aim of this study is to assess if it is possible to determine early (6 weeks of treatment)if a F-choline PET-CT could predict the response to abiraterone acetate or enzalutamide in post-docetaxel.