Internal Radiation Therapy With or Without External-Beam Radiation Therapy in Treating Patients With Localized Prostate Cancer

DISEASE CHARACTERISTICS:

Histologically confirmed adenocarcinoma of the prostate, meeting one of the following criteria:

Low-risk disease (T1-T2a, Gleason score ≤ 6, and PSA < 10 ng/mL)
Low intermediate-risk disease (T1-T2c, Gleason score ≤ 6, and PSA < 20 ng/mL OR T1-T2a, Gleason score 7, and PSA < 10 ng/mL)
No known nodal (N0 or NX) or distant (M0 or MX) metastases

No pubic arch interference, as defined by either of the following:

Maximum transrectal ultrasound-determined anterior-posterior (z-axis) dimension < 4.3 cm
No more than 25% prostate volume blocked (by pubic arch) on CT scan simulation at A10°I beam's eye view
Prostate planimetry volume ≤ 60 cc as determined by step-section transrectal ultrasound
American Urological Association voiding symptom index ≤ 12
Peak uroflow rate (Q_max) ≥ 12 cc/second
Post-void ultrasound bladder residual volume ≤ 100 cc

PATIENT CHARACTERISTICS:

Zubrod performance status 0-1
Life expectancy ≥ 5 years
WBC > 2,000/μL
Platelet count > 100,000/μL
PT < 1.5 times upper limit of normal
No diabetes mellitus associated with vascular ulcers or wound-healing problems
No blood dyscrasias
No inflammatory bowel disease
No connective tissue disorder
No other prior or concurrent invasive malignancy (except nonmelanoma skin cancer) or lymphomatous or hematological malignancy (except chronic lymphocytic leukemia/lymphoma) unless patient has been continually disease-free for ≥ 5 years
No medical or psychiatric condition that would preclude giving informed consent or complying with study treatment
Able to undergo anesthesia

PRIOR CONCURRENT THERAPY:

No prior transurethral resection of the prostate
No prior prostatic cryoablation or high-intensity focused ultrasound
No prior prostatectomy
No prior prostatic enucleation
No prior pelvic external beam radiotherapy
No prior radionuclide prostate brachytherapy
No prior hemi- or total hip arthroplasty
Neoadjuvant androgen suppression therapy allowed provided it was initiated 2-6 months prior to study entry and its total duration is ≤ 6 months
No concurrent anticoagulation therapy, including heparin or coumadin