Inclusion Criteria

DISEASE CHARACTERISTICS:

- Diagnosis of prostate cancer

- Asymptomatic progressive disease despite androgen-deprivation therapy

- Progression must occur during androgen-deprivation therapy comprising
orchiectomy or luteinizing hormone-releasing hormone (LHRH) analogue with
or without antiandrogen AND after antiandrogen withdrawal

- Concurrent LHRH monotherapy (i.e., LHRH analogs, such as leuprolide
acetate or goserelin) required in patients who did not undergo prior
bilateral orchiectomy to assure testicular androgen suppression

- Recurrent disease, as indicated by at least 1 of the following:

- Prostate-specific antigen (PSA) at baseline ≥ 2.0 ng/mL

- Biopsy-confirmed local recurrence

- Increase in size of measurable lesions on radiographic study

- New lesion on a nuclear bone scan

- Two successive increases in serum PSA measured at least 1 week apart

PATIENT CHARACTERISTICS:

- ECOG performance status 0-2

- Life expectancy ≥ 12 weeks

- Platelet count ≥ 100,000/mm^3

- Hemoglobin ≥ 9.0 g/dL

- Bilirubin ≤ 2.0 mg/dL

- SGOT ≤ 4 times upper limit of normal

- Creatinine ≤ 2.0 mg/dL

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

PRIOR CONCURRENT THERAPY:

- See Disease Characteristics

- At least 28 days since prior radiotherapy and recovered

- At least 28 days since prior flutamide OR at least 42 days since prior bicalutamide
or nilutamide

- Patients who have previously progressed despite antiandrogen withdrawal and who
have started antiandrogens without reduction of serum PSA are eligible without
requiring a 28- or 42-day washout interval after antiandrogen withdrawal

- No other prior systemic therapies, except androgen-deprivation therapy (i.e.,
orchiectomy or LHRH analogues only) or antiandrogens

- Surgery, brachytherapy, external-beam radiotherapy, and cryotherapy are not
considered systemic therapies

- No other concurrent anticancer therapy

- No concurrent use of any of the following:

- Finasteride

- Other investigational 5α-reductase inhibitors

- Anabolic steroids

- Alpha-receptor blockers (e.g., indoramin, tamsulosin hydrochloride, prazosin,
terazosin, alfuzosin hydrochloride, and doxazosin)

- Drugs with antiandrogenic properties (e.g., spironolactone, flutamide,
bicalutamide, cimetidine, ketoconazole, metronidazole, and progestational
agents)

- Products containing selenium ≥ 75 mcg or vitamin E ≥ 100 IU

- Saw palmetto

- EG6761

- No concurrent radiotherapy, including palliative radiotherapy for pain control