RATIONALE: Testosterone can stimulate the growth of prostate cancer cells. Hormone therapy using leuprolide and flutamide may fight prostate cancer by reducing the production of testosterone. It is not yet known whether receiving leuprolide and flutamide is more effective than receiving no further therapy.

PURPOSE: Randomized phase III trial to determine the effectiveness of hormone therapy in treating patients who have stage I or stage II prostate cancer that is at high risk of recurrence and who have already undergone surgery.

OBJECTIVES:

• Determine the effect of one year of adjuvant hormonal ablation on disease-free survival at 5 years in node-negative radical prostatectomy patients at high risk for progression.
• Determine the effect of this treatment on the incidence of androgen independent prostate cancer and on disease specific and overall survival.
• Determine the impact of one year of total androgen ablation on quality of life and serum testosterone levels.
• Assess differences in quality of life between wives of patients in the androgen ablation condition compared to wives of patients in the control condition.
• Obtain blood samples from patients at high risk for failure post-prostatectomy to evaluate serum markers of prognosis.

OUTLINE: This is a randomized study. Patients are randomized to one of two treatment arms.

• Arm I: Patients receive leuprolide intramuscularly once every 3 months and oral flutamide three times daily for 1 year.
• Arm II: Patients receive no initial treatment. Quality of life is assessed every 6 months for 5 years. Quality of life of wives/partners of patients is assessed every 6 months for two years.

Patients are followed every 3 months for 1 year and then every 6 months for 4 years.

PROJECTED ACCRUAL: A total of 496 patients (248 per treatment arm) will be accrued for this study within 3.5 years.

• Drug: flutamide
• Drug: leuprolide acetate

DISEASE CHARACTERISTICS:

• Histologically confirmed organ confined stage I or II (T1-T2c) prostate cancer treated with radical prostatectomy and bilateral pelvic lymph node dissection

  • Radical prostatectomy performed within 90 days of enrollment AND
  • PSA less than 0.1 ng/mL

• Must be at high risk of clinical or biochemical failure post-prostatectomy as defined by at least one of the following:

  • For patients with prior androgen ablation (up to 3 months):

    • Gleason score at least 8 on pretreatment biopsy OR
    • Seminal vesicle invasion OR
    • Pretreatment biopsy Gleason score at least 7 and extraprostatic extension with positive surgical margins in prostatectomy specimen

  • For patients without prior androgen ablation:

    • Gleason grade sum score at least 8 on radical prostatectomy specimen OR
    • Seminal vesicle invasion regardless of grade OR
    • Extraprostatic extension and positive surgical margins and Gleason sum at least 7
• No evidence of metastatic disease

PATIENT CHARACTERISTICS:

Age:

• Not specified

Performance status:

• Not specified

Life expectancy:

• Not specified

Hematopoietic:

• Not specified

Hepatic:

• Liver function tests less than 2 times normal

Renal:

• Not specified

Other:

• No contraindications to the use of LHRH agonists or antiandrogens
• No active secondary malignancy in the past 5 years except squamous or basal cell skin cancer
• No concurrent medical condition that would preclude participation in this study

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• Not specified

Chemotherapy:

• Not specified

Endocrine therapy:

• See Disease Characteristics

Radiotherapy:

• No prior radiotherapy for prostate cancer

Surgery:

• See Disease Characteristics

• National Cancer Institute (NCI)
• Eastern Cooperative Oncology Group