Radiation Therapy in Treating Women With Localized Breast Cancer

OBJECTIVES: * Compare late normal tissue effects of standard vs 2 different dose levels of hypofractionated adjuvant whole breast radiotherapy, in terms of changes in photographic breast appearance, in women with localized breast cancer who are at average or low risk of recurrence. * Compare tumor control in patients treated with these regimens. OUTLINE: This is a randomized, multicenter study. Patients are stratified according to participating center. Patients are randomized to 1 of 3 treatment arms. * Arm I (control): Patients undergo standard radiotherapy 5 days a week for 5 weeks. * Arm II: Patients undergo hypofractional radiotherapy once a week for 5 weeks. * Arm III: Patients undergo hypofractional radiotherapy (at a lower dose than arm II) once a week for 5 weeks. After completion of study treatment, patients are followed annually for 5-10 years. PROJECTED ACCRUAL: A total of 900 patients (300 per treatment arm) will be accrued for this study within 12 months.