SU5416 Compared to Dexamethasone in Treating Patients With Progressive Prostate Cancer That Has Not Responded to Hormone Therapy

DISEASE CHARACTERISTICS: * Histologically confirmed prostate cancer not amenable to curative treatment with surgery or radiotherapy * Progressive disease defined by 1 of the following criteria: * New bone scan lesions * New or progressive radiologic lesions * Sequential increases in PSA on at least 2 successive measurements no less than 2 weeks apart of at least 50% above nadir on prior therapy provided absolute value at time of enrollment is at least 5 ng/mL * Progressive disease, as defined above, despite adequate hormonal therapy defined by all of the following: * Continued treatment with an LHRH agonist or prior orchiectomy * Sequential or concurrent treatment with an antiandrogen (e.g., flutamide, nilutamide, or bicalutamide) * Trial of antiandrogen withdrawal at least 4 weeks prior to study * CNS metastasis allowed if: * Previously treated * Neurologically stable * Oral or intravenous steroids or anticonvulsants not required * Brain scan (CT or MRI) within the past 2 weeks shows no active or residual disease * Negative brain scan required if neurologic signs or symptoms suggestive of CNS metastasis PATIENT CHARACTERISTICS: Age: * 18 and over Performance status: * WHO 0-1 Life expectancy: * Not specified Hematopoietic: * WBC at least 3,000/mm\^3 * Platelet count at least 75,000/mm\^3 Hepatic: * Bilirubin no greater than 1.5 mg/dL * Transaminases no greater than 2.5 times upper limit of normal Renal: * Creatinine no greater than 2.0 mg/dL OR * Creatinine clearance at least 60 mL/min Cardiovascular: * No uncompensated coronary artery disease * No history of myocardial infarction or severe unstable angina within the past 6 months * No severe peripheral vascular disease associated with diabetes mellitus * No deep venous or arterial thrombosis within the past 3 months Pulmonary: * No pulmonary embolism within the past 3 months Other: * Not pregnant * Fertile patients must use effective contraception * No significant uncontrolled underlying medical or psychiatric illness * No serious active infection * No other prior or concurrent malignancy except nonmelanoma skin cancer unless completed therapy and considered to be at less than 30% risk of relapse * No history of severe allergic or anaphylactic reactions to paclitaxel or docetaxel PRIOR CONCURRENT THERAPY: Biologic therapy: * Not specified Chemotherapy: * No prior systemic chemotherapy * No other concurrent chemotherapy * No other concurrent investigational antineoplastic drugs Endocrine therapy: * See Disease Characteristics Radiotherapy: * See Disease Characteristics * At least 4 weeks since prior radiotherapy * No concurrent radiotherapy Surgery: * See Disease Characteristics * At least 4 weeks since prior major surgery