RATIONALE: Internal radiation uses radioactive material placed directly into or near a tumor to kill tumor cells. Specialized radiation therapy that delivers a high dose of radiation directly to the tumor may kill more tumor cells and cause less damage to normal tissue.

PURPOSE: This phase II trial is studying the side effects of internal radiation therapy when given with or without external-beam radiation therapy and to see how well it works in treating patients with localized prostate cancer.

OBJECTIVES:

Primary

• Evaluate the tolerability of 2 radiotherapeutic regimens (high dose-rate brachytherapy [HDR] with or without image-guided intensity-modulated hypofractionated external beam radiotherapy [EBRT]), as measured by the Common Terminology Criteria for Adverse Events (CTCAE v3.0), in patients with localized prostate cancer.

Secondary

• Identify any associations between dose-volume parameters for organs at risk and the rate and severity of genitourinary or gastrointestinal adverse events.
• Evaluate patient preference with regard to selection of a second treatment (a second HDR brachytherapy session or an EBRT session).
• Evaluate patient-reported health-related quality of life (HRQOL) as measured by validated HRQOL instruments for 5 years.
• Describe the probability of freedom from biochemical and clinical failure.
• Describe the probability of freedom from salvage androgen suppression.

OUTLINE: Patients undergo high dose-rate (HDR) brachytherapy (2 fractions ≥ 5 hours apart). Beginning 2-4 weeks after completion of the first HDR brachytherapy session, patients undergo either a second session of HDR brachytherapy (2 fractions ≥ 5 hours apart) OR image-guided intensity-modulated hypofractionated external beam radiotherapy once daily 5 days a week for 3 weeks.

Quality of life is assessed at baseline, prior to the second treatment session, at 1 and 6 months after completion of treatment, every 6 months for 3 years, and then annually for 2 years.

After completion of study treatment, patients are followed at 1 and 6 months, every 6 months for 3 years, and then annually for 2 years.

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