Radiation therapy in the management of breast cancer.

Radiation therapy (RT) plays an essential role in the management of breast cancer by eradicating subclinical disease after surgical removal of grossly evident tumor. Radiation reduces local recurrence rates and increases breast cancer-specific survival in patients with early-stage breast cancer after breast-conserving surgery and in node-positive patients who have undergone mastectomy. This article reviews the following topics: (1) the rationale for adjuvant RT and the evidence for its use in noninvasive and invasive breast cancer, (2) RT delivery techniques for breast-conserving therapy such as hypofractionated RT, partial breast irradiation, and prone irradiation, and (3) indications for PMRT.