DISEASE CHARACTERISTICS:

• Histologically confirmed adenocarcinoma of the prostate

  • Localized disease
  • Known Gleason grade
• Received prior external-beam radiotherapy, brachytherapy, or radical prostatectomy
• Candidate for intermittent androgen-ablation therapy

• Minimum of 3 PSA values above the nadir PSA measured ≥ 1 month apart after treatment AND meets 1 of the following criteria:

  • PSA level ≥ 2.0 ng/mL and < 100 ng/mL in patients who underwent prior radical prostatectomy with or without radiotherapy
  • PSA level ≥ 3.0 ng/mL and < 100 ng/mL in patients who underwent external beam radiotherapy (at any time) or brachytherapy > 3 years ago
  • PSA level ≥ 6.0 ng/mL and < 100 ng/mL in patients who underwent brachytherapy within the past 3 years
• Serum testosterone ≥ 250 ng/dL
• Negative bone scan within the past 12 months
• No distant metastases

PATIENT CHARACTERISTICS:

Inclusion criteria:

• ECOG performance status 0-1
• Able to read and write, understand instructions related to study procedures, and give written informed consent
• Able to swallow and retain oral medication
• Able and willing to participate in the full study

Exclusion criteria:

• Unstable serious concurrent medical conditions including, but not limited to, any of the following:

  • Myocardial infarction
  • Unstable angina
  • Cardiac arrhythmias
  • Clinically evident congestive heart failure or cerebrovascular accident within the past 6 months
  • Uncontrolled diabetes
  • Peptic ulcer disease
• Alkaline phosphatase, ALT, or AST > 2 times upper limit of normal (ULN)
• Bilirubin > 1.5 times ULN
• Serum creatinine > 1.5 times ULN
• Other malignancy within the past 5 years except curatively treated basal or squamous cell skin cancer or Ta bladder cancer with negative surveillance cystoscopy within the past 2 years
• History or current evidence of drug or alcohol abuse within the past year
• History of any illness that, in the opinion of the investigator, might confound the results of the study or pose additional risk to the patient
• Known hypersensitivity to any 5α-reductase inhibitor or to any drug chemically related to dutasteride
• Known hypersensitivity to bicalutamide or to any drug chemically related to bicalutamide

PRIOR CONCURRENT THERAPY:

• See Disease Characteristics

• No prior treatment for prostate cancer with any of the following:

  • Chemotherapy

  • Hormonal therapy (e.g., megestrol, medroxyprogesterone, cyproterone, or diethylstilbestrol) within the past year

    • May have received ≤ 12 months of neoadjuvant or adjuvant androgen-deprivation therapy provided the therapy was discontinued > 1 year ago
  • Glucocorticoids (except inhaled or topical drugs) within the past 3 months
  • Ketoconazole
  • Luteinizing hormone releasing-hormone analogs (e.g., leuprolide or goserelin) or nonsteroidal antiandrogens (e.g., bicalutamide or flutamide) within the past year
• More than 30 days since prior and no other concurrent investigational agents

• More than 1 year since prior and no concurrent use of the following medications:

  • Finasteride
  • Dutasteride
  • Other investigational 5α-reductase inhibitors
  • Anabolic steroids
  • Medications with antiandrogenic properties (e.g. spironolactone, flutamide, ketoconazole, metronidazole, progestational agents)

  • Over-the-counter or herbal preparations such as cimetidine, saw palmetto, selenium (> 75 mcg), or vitamin E (> 100 IU)

    • Concurrent use of a multivitamin is allowed provided the amounts of vitamin E and selenium do not exceed 100 IU and 75 mcg, respectively
    • Patients who had been using saw palmetto are eligible provided a 2 week washout period is observed
    • Patients who had been using vitamin E > 100 IU but ≤ 400 IU are eligible provided a 2 week washout period is observed
• No coronary bypass surgery within the past 6 months