• Occurrence of chronic grade 2 or higher toxicity as measured by RTOG/EORTC late morbidity scoring scheme at 1, 4, 8, and 12 months after treatment, then every 6 months for 5 years, then annually [ Designated as safety issue: Yes ]
  

• Disease free survival at 1, 4, 8, and 12 months after treatment, then every 6 months for 5 years, then annually [ Designated as safety issue: No ]
  

OBJECTIVES:

• Compare the efficacy of neutron and photon radiotherapy vs hypofractionated intensity modulated radiation, in terms of a lower frequency of chronic complication rate (chronic toxicity and disease-free survival), in patients with favorable to intermediate prognosis, stage I-III adenocarcinoma of the prostate.

OUTLINE: This is a randomized, multicenter study. Patients are stratified according to stage of disease (T1 vs T2 vs T3). Patients are randomized to 1 of 2 treatment arms.

• Arm I: Patients undergo neutron radiotherapy over 15-45 minutes 5 days a week for 2 weeks followed by photon radiotherapy over 15-45 minutes 5 days a week for 5 weeks.
• Arm II: Patients undergo photon radiotherapy over 15-45 minutes 5 days a week for 5 weeks followed by hypofractionated photon irradiation over 15-45 minutes 5 days a week for 2 weeks.

After completion of study treatment, patients are followed periodically for 5 years and then yearly thereafter.

PROJECTED ACCRUAL: A total of 300 patients (150 per treatment arm) will be accrued for this study.

DISEASE CHARACTERISTICS:

• Histologically confirmed adenocarcinoma of the prostate

  • Stage I-III disease (T1-T3, N0, M0)

  • No clinical or radiographic evidence of metastasis

    • If prostate-specific antigen (PSA) ≥ 10.0 ng/mL and Gleason score is 7, a radioisotope bone scan must show no evidence of metastasis
    • No evidence of lymphatic or visceral metastases of the abdomen or pelvis on CT scan or MRI
• PSA ≤ 20 ng/mL
• Gleason score ≤ 7 (if stage T3 , score must be < 7)

PATIENT CHARACTERISTICS:

Performance status

• Not specified

Life expectancy

• More than 10 years

Hematopoietic

• Not specified

Hepatic

• Not specified

Renal

• Not specified

Other

• No other malignancy within the past 5 years except basal cell or squamous cell skin cancer

PRIOR CONCURRENT THERAPY:

Endocrine therapy

• Prior hormonal therapy allowed provided it was initiated no more than 2 months ago, and may include the following:

  • Luteinizing hormone-releasing hormone agonists (e.g., goserelin, leuprolide)
  • Anti-androgens (e.g., flutamide, bicalutamide)

Radiotherapy

• No prior pelvic irradiation

Surgery

• No prior radical prostatectomy