Although these data support a role for chemotherapy combinations, such as estramustine and docetaxel, in the treatment of HRPC, further studies are needed to determine the relative contribution of estramustine to the efficacy of docetaxel/estramustine regimen. In this context, we propose to randomize patients with hormone resistant prostate cancer between docetaxel/estramustine/prednisone and docetaxel/prednisone in a phase II study. The principal endpoint will be the efficacy in term of PSA response. We chose to use the weekly regimen as described by Oudard since the toxicity of this regimen is well described and is easily manageable in our experience.