DISEASE CHARACTERISTICS:

• Histologically proven previously treated adenocarcinoma of the prostate

• Prior definitive therapy must have occurred at least 6 months, but no more than 10 years, prior to study

  • Definitive therapy is defined as one of the following:

    • Prior radical prostatectomy
    • Radiotherapy to the prostate no more than 3 months before prostatectomy
    • Brachytherapy
    • Brachytherapy with external beam radiotherapy given as single therapy
    • External beam radiation therapy alone
• Must have a PSA level between 1-10 nu/mL, with a rise of at least 1 nu/mL above the nadir produced by definitive therapy
• No evidence of local recurrence
• No metastatic disease

PATIENT CHARACTERISTICS:

Age:

• Not specified

Performance status:

• ECOG 0-2

Life expectancy:

• Not specified

Hematopoietic:

• Not specified

Hepatic:

• Bilirubin no greater than 2 times upper limit of normal (ULN)
• SGOT/SGPT no greater than 2 times ULN

Renal:

• Creatinine no greater than 2 times ULN

Other:

• Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• Not specified

Chemotherapy:

• No prior chemotherapy for prostate cancer

Endocrine therapy:

• At least 2 years since finasteride or other 5a-reductase inhibitors
• At least 12 months since prior hormone therapy for prostate cancer
• No more than 6 months of prior hormone therapy
• No corticosteroids in excess of standard replacement doses
• No concurrent systemic steroids
• No other concurrent antiandrogenic drugs or 5a-reductase inhibitors

Radiotherapy:

• See Disease Characteristics
• No concurrent palliative radiotherapy

Surgery:

• See Disease Characteristics
• No orchiectomy