Postmastectomy radiation in patients with one to three positive axillary nodes receiving adjuvant chemotherapy: An unresolved issue.

The rationale for postmastectomy radiation is based on the prevention of locoregional recurrence in the chest wall, regional lymphatics, or both. The randomized trials of postmastectomy radiation in patients with one to three positive nodes receiving adjuvant chemotherapy have shown a proportional reduction in locoregional recurrence rates of two thirds. The absolute benefit, however, varies with the magnitude of the risk in patients who do not receive radiation. The survival benefit from radiation is best explained by the prevention of an isolated locoregional recurrence, which could serve as a source of fatal distant metastases and parallels the difference in the total incidence of distant metastases. The current dilemma is to identify patients with one to three positive nodes who have had an adequate axillary dissection and remain at substantial risk for a locoregional recurrence despite adjuvant chemotherapy. The routine use of postmastectomy radiation in all axillary node-positive patients requires further evaluation.