The changing role of radiation therapy in the treatment of primary breast cancer.

The role of radiation in the management of breast cancer has seen extraordinary change in the past 15 years. The primary treatment of early breast cancer once required mastectomy. Today, a local tumor excision followed by postoperative radiation is an established alternative of equal efficacy. Postoperative chest wall and/or lymphatic irradiation was once nearly routine following mastectomy; later, as adjuvant chemotherapy came into widespread use, its usage declined markedly. Today however, evidence is mounting that the addition of postoperative radiation to adjuvant chemotherapy and surgery can improve local-regional control and survival in selected subsets of these patients. In unresectable breast cancer, radiation was once the primary modality of treatment. Today it is part of a combined modality approach attempting to reduce these patients' high rates of both distant and local-regional failure.