Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically or cytologically confirmed adenocarcinoma of the prostate

- Advanced disease

- Must have androgen-independent prostate cancer meeting the following criteria:

- Evidence of rising prostate-specific antigen (PSA) level and absolute value ≥ 5
ng/mL based on 2 measurements taken ≥ 2 weeks apart (measurements must be done
after androgen deprivation [orchiectomy or luteinizing hormone-release hormone
(LHRH) analogue] and antiandrogen withdrawal)

- Rising PSA required for ≥ 28 days after antiandrogen or progestational therapy for
prostate cancer (≥ 42 days after bicalutamide or nilutamide)

- Testosterone < 50 ng/mL (unless surgically castrated)

- Measurable or evaluable disease

- PSA elevation constitutes evaluable disease

PATIENT CHARACTERISTICS:

Performance status

- ECOG 0-2

Life expectancy

- Not specified

Hematopoietic

- WBC > 3,000/mm^3

- Neutrophil count ≥ 1,500/mm^3

- Platelet count ≥ 100,000/mm^3

- Hemoglobin ≥ 8 g/dL (transfusion or epoetin alfa allowed)

- No bleeding diathesis (e.g., disseminated intravascular coagulation or clotting
factor deficiency)

Hepatic

- Bilirubin normal

- Gilbert's disease with bilirubin ≤ 3 times upper limit of normal (ULN) allowed
in the absence of other etiology (e.g., hemolysis-reticulocyte count < 5%) and
liver function tests normal

- SGOT and/or SGPT ≤ 2 times ULN

- INR < 1.6

Renal

- Creatinine < 2.5 mg/dL

Cardiovascular

- No unstable cardiac disease requiring medication

- No new onset crescendo or rest angina

- Stable exertional angina allowed

Other

- Fertile patients must use effective barrier contraception during and for 3 months
after completion of study treatment

- No other active malignancy within the past 2 years except nonmelanoma skin cancer or
superficial bladder cancer

- No history of significant neurologic or psychiatric disorders, including psychotic
disorders, dementia, or seizures

- No other serious illness or medical condition

- No active infection

- No known hypersensitivity to active or inactive excipients of fulvestrant (e.g.,
castor oil or mannitol)

PRIOR CONCURRENT THERAPY:

Biologic therapy

- Prior retinoids, vaccines, and cytokines are not considered cytotoxic and are allowed

Chemotherapy

- No more than 1 prior cytotoxic chemotherapy regimen

- More than 3 weeks since prior chemotherapy (6 weeks for mitomycin or nitrosoureas)

- No concurrent chemotherapy

Endocrine therapy

- See Disease Characteristics

- Prior glucocorticoids, antiandrogens, progestational agents, estrogens, and LHRH
analogues are not considered cytotoxic and are allowed

- At least 4 weeks since prior flutamide (6 weeks for bicalutamide or nilutamide)

- Concurrent megestrol acetate allowed at a stable dose of ≤ 40 mg/day

- Concurrent androgen deprivation using LHRH analogues allowed but must continue during
study treatment or orchiectomy is required to maintain castrate levels of
testosterone

Radiotherapy

- More than 3 weeks since prior radiotherapy

- No concurrent radiotherapy

Surgery

- See Disease Characteristics

- See Endocrine therapy

Other

- Recovered from all prior therapy

- Prior cholecalciferol analogues, ketoconazole, aminoglutethimide,
peroxisome-proliferation-activated receptor-gamma agonists or antagonists, or PC-SPES
are not considered cytotoxic and are allowed

- No prior long-term anticoagulation therapy (antiplatelet therapy allowed)

- More than 4 weeks since prior investigational drugs

- No other concurrent anticancer therapy (e.g., PC-SPES)

- No concurrent bisphosphonates unless receiving a stable dose at study entry

- No concurrent therapy that may alter androgen metabolism or androgen levels

- No concurrent full anticoagulation