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)