Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically confirmed adenocarcinoma of the prostate diagnosed within the past 180
days and at intermediate-risk for recurrence by meeting ≥ 1 of the following
criteria:

- Gleason score > 7

- PSA > 10 and ≤ 20 ng/mL

- Baseline serum PSA value performed within 60 days with an FDA-approved
assay (e.g., Abbott, Hybritech)

- Baseline PSA must not be obtained during any of the following time
frames:10-day period after prostate biopsy, after initiation of
androgen-deprivation therapy, or within the past 30 days after
discontinuation of finasteride (90 days for dutasteride)

- Clinical stage T2b or T2c disease

- Patients previously diagnosed with low-risk (Gleason score < 6, clinical stage <
T2a, and PSA < 10 ng/mL) prostate cancer undergoing active surveillance who are
re-biopsied and found to have intermediate-risk disease according to the
protocol criteria are eligible for enrollment within 6 months of the repeat
biopsy procedure

- Patients with Gleason Score ≥ 8, PSA > 20 ng/mL, OR clinical stage ≥ T3 are
ineligible for this trial

- If findings of extracapsular extension or seminal vesicle invasion are noted on
prostate MRI, this study, if used, will not render patients ineligible for
accrual to this protocol

- Primary tumor staging for eligibility purposes is to be based on palpable or
core biopsy evidence only with respect to extracapsular extension or seminal
vesicle involvement

- No patients with all 3 intermediate-risk factors who also have ≥ 50% of the number of
their biopsy cores positive for cancer

- The percentage of biopsy cores involved will only be considered with respect to
eligibility for those patients with all 3 of the above risk factors (i.e.,
patients with one or two of the above risk factors are eligible irrespective of
the percentage of biopsy cores involved)

- Clinically negative lymph nodes as established by imaging (pelvic and/or abdominal CT
scan or MRI), nodal sampling, or dissection within the past 60 days (required for
patients with 2-3 risk factors)

- Abdominal imaging not required for a single intermediate-risk factor (these
studies may be obtained at the discretion of the treating physician)

- Lymph nodes that are equivocal or questionable by imaging allowed without biopsy
if nodes ≤ 1.5 cm

- Any node > 1.5 cm on imaging requires a negative biopsy

- No evidence of bone metastases on bone scan within the past 60 days

- Bone scan not required for patients with a single intermediate-risk factor (scan
may be obtained at the discretion of the treating physician)

- Equivocal bone scan findings allowed if plain film x-rays negative for
metastasis

PATIENT CHARACTERISTICS:

- Zubrod performance status 0-1

- ANC ≥ 1,800/mm^3*

- Platelet count ≥ 100,000/mm^3*

- Hemoglobin ≥ 8.0 g/dL (transfusion or other intervention to achieve level allowed)*

- NOTE: *For patients undergoing brachytherapy only.

- Fertile patients must use effective contraception during and for the 3 months after
cessation of protocol treatment

- No invasive malignancy or hematological malignancy (e.g., leukemia, lymphoma,
myeloma) within the past 5 years except adequately treated non-melanomatous skin
cancer

- Prior diagnoses of carcinoma in situ allowed

- No severe or active co-morbidity with 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, within the past 30 days

- Hepatic insufficiency resulting in clinical jaundice and/or coagulation defects

- Laboratory tests for liver function and coagulation parameters not required
for entry into this protocol

- AIDS based upon current CDC definition

- HIV testing not required for entry into this protocol

- HIV-seropositive patients who do not meet criteria for diagnosis of AIDS
allowed

PRIOR CONCURRENT THERAPY:

- See Disease Characteristics

- No prior radical surgery (prostatectomy), high-intensity focused ultrasound, or
cryosurgery for prostate cancer

- No prior hormonal therapy, such as LHRH agonists (e.g., goserelin, leuprolide),
antiandrogens (e.g., flutamide, bicalutamide), estrogens (e.g., DES), or bilateral
orchiectomy

- No finasteride within past 30 days (90 days for dutasteride)

- No prior or concurrent cytotoxic chemotherapy for prostate cancer

- Prior chemotherapy for a different cancer allowed

- No prior radiotherapy (RT), including brachytherapy, to the region of the study
cancer that would result in overlap of RT fields

- Patients undergoing brachytherapy must have transrectal ultrasound confirmation
of prostate volume < 60 cc, AUA score ≤ 15 within the past 60 days of
registration, and no history of prior transurethral resection of the prostate
(TURP)

- TURP allowed for patients who receive external-beam radiation therapy only