Inclusion Criteria

DISEASE CHARACTERISTICS:

- Pathologically proven adenocarcinoma of the prostate cancer meeting 1 of the
following criteria:

- Gleason ≥ 7and post-operative PSA nadir > 0.2 ng/ml with any pT classification

- Gleason ≥ 8, post-operative PSA nadir ≤ 0.2 ng/ml and ≥ pT3a classification

- Must have undergone radical prostatectomy within the past year

- PSA ≤ 0.2 ng/mL at the time of study registration

- PSA must be obtained within 6 weeks (42 days) prior to study registration

- No lymph node or distant metastases (N0, M0), based upon the following minimum
diagnostic workup:

- History and physical examination within 8 weeks prior to study registration

- Bone scan and CT or MRI of the pelvis and no evidence of osseous metastases on
bone scan within 16 weeks prior to study registration

- No pelvic lymph nodes > 1.5 cm in greatest dimension on CT scan or MRI of the pelvis
within 16 weeks prior to study registration, unless the enlarged lymph node is
biopsied and negative

PATIENT CHARACTERISTICS:

- Zubrod performance status 0-1

- ANC ≥ 2,000/mm³

- Platelet count ≥ 100,000/mm³

- Hemoglobin ≥ 8.0 g/dL (transfusion or other intervention to achieve hemoglobin ≥ 8.0
g/dL is acceptable)

- ALT and AST ≤ 1.5 times upper limit of normal (ULN)

- Alkaline phosphatase ≤ 2.5 times ULN

- Total bilirubin ≤ 1.2 times ULN

- No other invasive malignancy within the past 3 years except non-melanomatous skin
cancer

- No active, severe co-morbidity, including any of the following:

- Unstable angina and/or congestive heart failure requiring hospitalization within
the past 6 months

- Transmural myocardial infarction within the past 6 months

- Acute bacterial or fungal infection requiring intravenous antibiotics

- Chronic obstructive pulmonary disease exacerbation or other respiratory illness
requiring hospitalization or precluding study therapy

- AIDS

- HIV testing is not required for study entry

- No prior allergic reaction to the study drug(s)

PRIOR CONCURRENT THERAPY:

- No prior systemic chemotherapy for prostate cancer

- More than 3 years since prior chemotherapy for a different cancer

- No prior androgen deprivation for treatment of prostate cancer

- Prior use of hormonal agents, such as finasteride or dutaseride, for treatment
of benign prostatic hypertrophy is allowed

- No prior radiotherapy to the region of the prostate that would result in overlap of
radiotherapy fields