DISEASE CHARACTERISTICS: Histologically proven hormone refractory stage IV prostate cancer Hormone refractory disease is defined as: Progressive measurable disease OR Progressive disease by bone scan OR Increase in PSA by 50% over nadir level confirmed twice and measured at least two weeks apart Prior treatment with primary androgen ablative therapy with castrate levels of testosterone Minimum score of 2 on the McGill 6 point pain scale secondary to metastatic bony pain with an analgesic score of at least 4 No CNS metastases