DISEASE CHARACTERISTICS:

• Diagnosis of metastatic adenocarcinoma of the prostate
• Failed initial hormone therapy AND experienced disease progression after treatment with ≥ 1 prior chemotherapy regimen containing docetaxel
• Prostate specific antigen ≥ 10 ng/mL
• No known CNS metastases

PATIENT CHARACTERISTICS:

Performance status

• ECOG 0-2

Life expectancy

• At least 4 months

Hematopoietic

• Not specified

Hepatic

• Bilirubin < 2 times upper limit of normal (ULN)
• SGOT and SGPT ≤ 2 times ULN

Renal

• Creatinine < 2 times ULN

Cardiovascular

• No history of deep vein thrombosis (DVT)

  • Patients with DVT who have been receiving anticoagulants for ≥ 6 months allowed
• No New York Heart Association class III or IV heart disease
• No uncontrolled congestive heart failure
• No life threatening cardiac dysrhythmia within the past 6 months
• No history of severe cardiovascular disease
• Triglycerides ≤ 2 times ULN

Pulmonary

• No history of pulmonary embolus

Other

• No other medical condition that would preclude study compliance
• No known hypersensitivity to estrogen
• Fertile patients must use effective contraception during and for 10 weeks after completion of study treatment

PRIOR CONCURRENT THERAPY:

Chemotherapy

• See Disease Characteristics

Endocrine therapy

• See Disease Characteristics

• At least 4 weeks since prior flutamide (6 weeks for bicalutamide)

  • Must have progressive disease after withdrawal of antiandrogen

• No intiation or continuation of luteinizing hormone-releasing hormone (LHRH) agonist therapy during study treatment for patients who have not been on LHRH therapy or who have been on LHRH therapy for < 1 month

  • Concurrent LHRH agonist therapy required for patients who have been on LHRH agonist therapy for > 1 month

Radiotherapy

• Recovered from prior radiotherapy

Surgery

• Recovered from prior surgery

Other

• At least 1 week since prior herbal supplements
• No concurrent herbal supplements