Abstract: Breast conservation is a safe and effective alternative to mastectomy for the majority of women with early-stage breast cancer. Adjuvant radiation therapy lowers the risk of recurrence within the breast and also confers a survival benefit. Although acute side effects of radiation therapy are generally well tolerated; efforts are ongoing to minimize the long-term side effects of radiation, most prominently atherosclerotic heart disease. Efforts to minimize radiation therapy are also underway. They include omitting treatment altogether in the elderly and using accelerated, hypofractionated whole-breast irradiation, and accelerated partial-breast irradiation. Several randomized studies are ongoing to determine the efficacy, safety, and appropriate patients for these shorter treatments.