OUTLINE: Patients who have undergone lumpectomy undergo either intracavitary balloon brachytherapy boost and hypofractionated, accelerated whole breast irradiation (AWBI) OR 3D-conformal radiotherapy (3D-CRT)/intensity-modulated radiotherapy (IMRT) boost and AWBI. Patients who have undergone mastectomy undergo hypofractionated, accelerated chest wall irradiation.