Division of Medical Oncology;
"Giovanni Borea" Hospital;
I-18038 Sanremo;
Italy;
Division of Medical Oncology;
Santo Spirito Hospital;
00186 Roma;
Italy;
Metastatic; castration-resistant; prostate; cancer; End; points; Progression-free; survival; Prostate-specifc; antigen; Chemotherapy; Palliative; response;