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