Radiation Therapy After Surgery in Treating Women With Early Stage Breast Cancer

OBJECTIVES: * Determine the benefits of radiotherapy schedules using fraction sizes larger than 2.0 Gy in terms of normal tissue responses, local-regional tumor control, quality of life, and economic consequences in women prescribed postoperative radiotherapy for early stage breast cancer. OUTLINE: This is a randomized, multicenter study. Patients are stratified according to center, type of surgery (mastectomy vs local excision), and breast boost (yes vs no). Patients are randomized to 1 of 3 treatment arms. * Arm I: Patients receive radiotherapy 5 times a week for 5 weeks for a total dose of 50 Gy. * Arm II: Patients receive radiotherapy 5 times a fortnight (i.e., Monday/Wednesday/Friday/Tuesday/Thursday/Monday, etc.) for 13 fractions over 5 weeks for a total dose of 41.6 Gy. * Arm III: Patients receive radiotherapy as in arm II for a total dose of 39 Gy. A breast boost is recommended in all arms for patients with microscopic evidence of invasive or in situ cancer at, or within 1 mm of, a resection margin. These patients receive radiotherapy for 5 fractions in 1 week for a total boost dose of 10 Gy. Quality of life is assessed at baseline and then at 6, 12, 24, and 60 months. Patients are followed annually for up to 20 years. PROJECTED ACCRUAL: A total of 2,010 patients (670 per arm) will be accrued for this study.