Mounting evidence for postmastectomy locoregional radiation therapy.

Postmastectomy locoregional radiation therapy markedly reduces the risk of locoregional recurrence. Several randomized trials, including two recently updated studies with 10- to 15-year follow-up, demonstrate an improvement in overall survival with radiation therapy. This improvement is seen in patients with one to three positive axillary lymph nodes, as well those with four positive nodes. Therefore, postmastectomy radiation therapy should be considered in all patients with node-positive breast cancer. Computed tomography (CT)-based treatment planning is recommended to minimize the cardiopulmonary morbidity of radiation therapy.