Chemotherapy With or Without Biological Therapy in Treating Patients With Metastatic Prostate Cancer That Has Not Responded to Hormone Therapy

DISEASE CHARACTERISTICS: Histologically confirmed adenocarcinoma of the prostate Evidence of progressive metastatic disease (e.g., bone, pelvic mass, lymph node, liver or lung metastases) Radiologic evidence of hydronephrosis only does not constitute evidence of metastatic disease Must not have an elevated serum alkaline phosphatase or PSA level as only evidence of disease If bone metastases only (i.e., lacking soft tissue disease), must have PSA level of at least 20 ng/mL If soft tissue metastases and/or visceral disease, must have either bidimensionally measurable disease or PSA level of at least 20 ng/mL Must have had prior bilateral orchiectomy or other primary hormonal therapy (e.g., estrogen therapy or LHRH blocker plus flutamide) with evidence of treatment failure No carcinomatous meningitis or brain metastases PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-2 Life expectancy: Not specified Hematopoietic: WBC at least 4,000/mm^3 Granulocyte count at least 2,000/mm^3 Platelet count at least 100,000/mm^3 Hepatic: See Disease Characteristics Bilirubin no greater than 1.5 mg/dL SGOT/SGPT no greater than 2 times upper limit of normal Renal: Creatinine no greater than 2.0 mg/dL OR Creatinine clearance at least 50 mL/min Cardiovascular: No active angina pectoris No New York Heart Association class III or IV heart disease No myocardial infarction within the past 6 months No deep venous thrombosis LVEF at least 50% by MUGA Other: Fertile patients must use effective contraception during and for 1 month after study Prior malignancy allowed provided curatively treated and disease free for appropriate time period for specific cancer No other serious medical illness or active infection that would preclude protocol therapy No concurrent prolonged exposure to sunlight No concurrent alcohol consumption PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: No prior chemotherapy, including neoadjuvant chemotherapy or single-agent estramustine Endocrine therapy: See Disease Characteristics If no prior bilateral orchiectomy, must continue LHRH agonist therapy (e.g., depot leuprolide or goserelin) At least 4 weeks since prior flutamide or flutamide with evidence of progressive disease At least 6 weeks since prior bicalutamide with evidence of progressive disease Radiotherapy: More than 4 weeks since prior radiotherapy No prior strontium chloride Sr 89, samarium Sm 153 lexidronam pentasodium, or other radioisotope therapies Surgery: See Disease Characteristics Other: Recovered from all toxic effects due to prior treatment for prostate cancer No concurrent milk, milk products, antacids, calcium-containing drugs, or any food with estramustine (arm I only) No concurrent vitamin supplements containing vitamin A (arm II only)