RESUMO
Radiation therapy is an important modality in the treatment of patients with breast cancer. While its efficacy in the treatment of breast cancer was known shortly after the discovery of x-rays, significant advances in radiation delivery over the past 20 years have resulted in improved patient outcomes. With the development of improved systemic therapy, optimizing local control has become increasingly important and has been shown to improve survival. Better understanding of the magnitude of treatment benefit, as well as patient and biological factors that confer an increased recurrence risk, have allowed radiation oncologists to better tailor treatment decisions to individual patients. Furthermore, significant technological advances have occurred that have reduced the acute and long-term toxicity of radiation treatment. These advances continue to reduce the human burden of breast cancer. It is important for radiation oncologists and nonradiation oncologists to understand these advances, so that patients are appropriately educated about the risks and benefits of this important treatment modality.