Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically confirmed stage T1-T3 adenocarcinoma of the prostate before radical
prostatectomy and lymph node dissection

- Must have undergone prostatectomy within the past 120 days

- Must meet at least 1 of the following pathologic criteria:

- Gleason sum at least 8

- pT3b (seminal vesicle), pT4, or N1

- Gleason sum of 7 and positive margin

- Preoperative PSA greater than 15 ng/mL, Gleason score greater than 7, or PSA
level greater than 10 ng/mL and Gleason score greater than 6

- Must have an undetectable PSA (no greater than 0.2 ng/mL) documented after surgery or
prior to adjuvant hormonal therapy (for patients initiating adjuvant hormonal therapy
prior to study)

- No evidence of metastatic disease on bone scan if PSA is 20 ng/mL or greater at
clinical diagnosis

- No distant metastatic disease

PATIENT CHARACTERISTICS:

Performance status:

- SWOG 0-1

Life expectancy:

- Not specified

Hematopoietic:

- Not specified

Hepatic:

- Not specified

Renal:

- Not specified

Cardiovascular:

- No uncontrolled congestive heart failure

- If history of cardiac disease, LVEF at least 50% by MUGA scan or 2-D echocardiogram

Other:

- No HIV positivity

- No other prior malignancy within the past 5 years except adequately treated basal
cell or squamous cell skin cancer or stage I or II cancer that is currently in
complete remission

PRIOR CONCURRENT THERAPY:

Biologic therapy:

- Not specified

Chemotherapy:

- Not specified

Endocrine therapy:

- Prior neoadjuvant hormonal therapy of no more than 4 months duration before radical
prostatectomy allowed

- Other concurrent adjuvant hormonal therapy allowed if initiated prior to study

- Concurrent low-dose megestrol (less than 40 mg/day) for hot flashes allowed

Radiotherapy:

- No prior radiotherapy

- No concurrent whole pelvis irradiation

- Concurrent radiotherapy allowed at the discretion of the physician

Surgery:

- See Disease Characteristics

- See Endocrine therapy

- Recovered from prior surgery

Other:

- No other prior or concurrent therapy for adenocarcinoma of the prostate