PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: At least 4 weeks since prior chemotherapy and recovered No concurrent chemotherapy Endocrine therapy: See Disease Characteristics At least 2 weeks since change in hormonal therapy (except to maintain castrate levels of testosterone), including prednisone or dexamethasone At least 8 weeks since prior suramin and/or serum concentration of suramin must be less than 50 micrograms/mL (replacement hydrocortisone allowed) Radiotherapy: See Disease Characteristics At least 4 weeks since prior radiotherapy and recovered No concurrent therapy to only measurable lesion Surgery: See Disease Characteristics No concurrent surgery