Docetaxel + Prednisone With or Without Radiation for Castrate Resistant Prostate Cancer

Most physicians would consider chemotherapy to be the standard for prostate cancer. In this study all participants will receive the standard chemotherapy. In addition, half the participants will also receive radiation therapy. It is hoped that the radiation therapy will provide additional benefit. The use of radiation therapy and chemotherapy for patients with this kind of cancer is not considered standard treatment at the present time. Participants will be randomized into groups (or Arms) by a computer program. Participants randomized to Arm 1 will receive chemotherapy alone. Participants in Arm 2 will receive chemotherapy and radiation therapy. Participants in both groups (Arm 1 and Arm 2) will receive standard chemotherapy with docetaxel and prednisone. Docetaxel is given through a needle in a vein in the arm every 3 weeks or 21 days. Participants will take a prednisone tablet once per day until 21 days after the last dose of docetaxel. In addition, all participants will be given a drug called dexamethasone twice daily for 6 doses to help with the side effects of docetaxel. Participants in Arm 2 will first receive radiation therapy to the pelvis and prostate gland. Radiation therapy will be delivered once a day, five days a week for a total of 8-9 weeks. Then beginning 4-6 weeks after the end of radiation therapy, chemotherapy will be given, as described above. In both Arms, the total number of cycles of docetaxel and prednisone will depend upon how the tumor responds to these drugs. All patients should receive a minimum of three cycles of chemotherapy.