Inclusion Criteria

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