Fulvestrant in Treating Patients With Recurrent Prostate Cancer

DISEASE CHARACTERISTICS: * Histologically confirmed adenocarcinoma of the prostate * Early recurrent disease, defined by 1 of the following criteria: * Prostate-specific antigen (PSA) ≥ 2.0 ng/mL AND clearly rising within the past 3 months for patients who underwent prior prostatectomy with or without radiotherapy * PSA ≥ 4.0 ng/mL AND clearly rising from the lowest value obtained within the past 6 months for patients who underwent prior definitive radiotherapy only * No evidence of clinical recurrence,\* as defined by the following criteria: * Digital rectal exam negative * No local recurrence by CT scan or MRI of the pelvis * No evidence of bone metastasis by bone scan NOTE: \*Prostascint scan results are not considered evidence of recurrence * Underwent prior curative treatment comprising radical prostatectomy with or without adjuvant radiotherapy OR definitive radiotherapy alone * Testosterone (total or free) \> than lower limit of normal PATIENT CHARACTERISTICS: Age * Any age Performance status * ECOG 0-1 Life expectancy * Not specified Hematopoietic * WBC \> 3,500/mm\^3 * Platelet count \> 100,000/mm\^3 * No history of bleeding diathesis Hepatic * INR \< 1.6 * Bilirubin ≤ 1.5 times upper limit of normal (ULN) * ALT or AST ≤ 2.5 times ULN * No severe hepatic impairment that would preclude study participation or compliance Renal * Creatinine ≤ 2.0 mg/dL * No severe renal impairment that would preclude study participation or compliance Cardiovascular * No unstable or uncompensated cardiac condition that would preclude study participation or compliance Pulmonary * No unstable or uncompensated respiratory condition that would preclude study participation or compliance Other * No history of hypersensitivity to active or inactive excipients of fulvestrant (e.g., castor oil) * No other severe condition that would preclude study compliance (e.g., abuse of alcohol or drugs or psychotic states) or participation PRIOR CONCURRENT THERAPY: Biologic therapy * Not specified Chemotherapy * Not specified Endocrine therapy * More than 6 months since prior neoadjuvant or adjuvant androgen deprivation therapy or luteinizing hormone-releasing hormone antagonist therapy * No other prior or concurrent hormonal therapy Radiotherapy * See Disease Characteristics * No concurrent radiotherapy Surgery * See Disease Characteristics Other * More than 4 weeks since prior experimental drug treatment * No concurrent anticoagulant therapy except antiplatelet therapy * No other concurrent therapy for prostate cancer * No other concurrent therapy known or suspected of altering androgen metabolism or androgen levels