Intensity-Modulated Radiation Therapy in Treating Patients With Stage I, Stage II, Stage III, or Stage IV Prostate Cancer

RATIONALE: Radiation therapy uses high-energy x-rays to kill tumor cells. Using scintigraphy to plan 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 I/II trial is studying the side effects and best way to give intensity-modulated radiation therapy and to see how well it works in treating patients with stage I, stage II, stage III, or stage IV prostate cancer.

OBJECTIVES: * To assess the feasibility of radioimmunoguided intensity-modulated radiotherapy (IMRT) for stage I-IV prostate cancer. * To determine the toxicity and tolerance of this regimen in these patients. * To determine the tumor response based on physical examination and serial measurements of the serum prostate-specific antigen (PSA) levels in these patients. * To determine the outcome of patients treated on this study with radioimmunoguided IMRT compared to 2 control groups of patients treated at Mayo Scottsdale Clinic (MSC). OUTLINE: Patients undergo radioimmunoguided intensity-modulated radiotherapy once daily, 5 days a week for 8½ weeks. Beginning the last week of radiotherapy, some patients receive leuprolide acetate intramuscularly every 3-4 months or goserelin subcutaneously every 3 months for 6 months, 12 months, or until disease progression. After completion of study treatment, patients are followed every 3-4 months for 1 year, every 6 months for 4 years and annually thereafter