Intensity-Modulated Radiation Therapy in Treating Patients With Localized Prostate Cancer

OBJECTIVES: * Determine the safety and efficacy of conventional vs hypofractionated high-dose intensity-modulated radiotherapy in patients with localized prostate cancer. * Determine the side effects of these regimens in these patients. * Determine whether hypofractionated radiotherapy schedules will improve the therapeutic ratio by either improving tumor control or reducing normal tissue side effects. * Compare acute and late treatment-related gastrointestinal and urological toxicity in these patients. * Determine different prostate-specific antigen-related endpoints for local failure and distant metastases. * Extend the database of patients treated to escalated doses with dose-volume histograms (DVHs) of normal tissues at risk and relate these to common toxicity endpoints. * Develop a model to estimate normal tissue complication probability (NTCP) of rectum and bladder for hypofractionated as well as conventional dose-escalated radiotherapy schedules. OUTLINE: This is a multicenter, randomized, pilot study. Patients are stratified according to risk of seminal vesicle involvement (low-risk vs moderate-risk or high-risk). * Hormone therapy: Patients receive androgen-deprivation therapy comprising an injection of luteinizing hormone-releasing hormone (LHRH) agonist once monthly for 3-6 months and oral cyproterone acetate beginning the week before the first LHRH agonist injection and continuing for at least 2 weeks after each LHRH agonist injection. Within one week after the last LHRH agonist injection, patients proceed to radiotherapy. * Radiotherapy: Patients are randomized to 1 of 3 treatment arms. * Arm I: Patients undergo conventional high-dose intensity-modulated radiotherapy (IMRT) in 37 fractions over 7.5 weeks. * Arm II: Patients undergo hypofractionated high-dose IMRT in 20 fractions over 4 weeks. * Arm III: Patients undergo hypofractionated high-dose IMRT in 19 fractions over 3.8 weeks. In all arms, treatment continues in the absence of unacceptable toxicity. Quality of life is assessed periodically during study treatment. After completion of study treatment, patients are followed periodically for up to 15 years. Peer Reviewed and Funded or Endorsed by Cancer Research UK PROJECTED ACCRUAL: A total of 2,163 patients will be accrued for this study.