PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: No prior chemotherapy No other concurrent chemotherapy Endocrine therapy: See Disease Characteristics At least 4 weeks since prior antiandrogens If patients have received prior antiandrogens, PSA levels are reassessed at 4 week intervals until there is no decrease in PSA levels before registration into this study Radiotherapy: Prior radiotherapy allowed Must have recovered from prior radiotherapy Concurrent radiotherapy for symptomatic bone lesion allowed Surgery: Not specified Other: No other concurrent therapeutic study