Radiation Therapy in Treating Patients With Stage II or Stage III Prostate Cancer

OBJECTIVES: Primary * Determine the rate of late grade 3 or greater genitourinary and gastrointestinal toxicity after treatment with external beam radiotherapy and high-dose rate brachytherapy in patients with stage II or III adenocarcinoma of the prostate. Secondary * Determine acute grade 3 or greater genitourinary and gastrointestinal toxicity in patients treated with this regimen. * Determine freedom from biochemical failure in patients treated with this regimen. * Determine overall survival of patients treated with this regimen. * Determine disease-specific survival of patients treated with this regimen. * Determine clinical relapse (local and/or distant) in patients treated with this regimen. * Develop a quality assurance process for high-dose rate prostate brachytherapy. OUTLINE: This is a multicenter study. Patients are stratified according to prostate-specific antigen (≤ 10 ng/mL vs 11-20 ng/mL), T stage (T1c-T2c vs T3a-T3b), combined Gleason score (2-6 vs 7 vs 8-10), prior hormonal therapy (no vs yes), and timing of high-dose rate brachytherapy (before external beam radiotherapy vs after external beam radiotherapy). Patients are followed at 3, 7, 9, and 12 months, every 6 months for 5 years, and then annually thereafter.