Postmastectomy radiation: then and now.

With the increased use of doxorubicin-based chemotherapy, chemoendocrine therapy, and high-dose chemotherapy with autologous bone marrow transplantation or peripheral blood progenitor-cell reinfusion, the role of postmastectomy radiation in the treatment of stages II-III breast cancer has been challenged. Despite these therapies, 20% to 30% of patients with four or more positive nodes, primary tumor size > or = 5 cm, or pectoral fascia involvement will develop an isolated locoregional recurrence. Postmastectomy radiation decreases the incidence of locoregional recurrence to < or = 10% in these high-risk patients, and modifications in technique can minimize long-term cardiac mortality. A recent meta-analysis has demonstrated a decrease in breast cancer mortality of approximately 10% with postmastectomy radiation, which is similar to the effect of adjuvant systemic therapy in axillary node-positive patients. Future studies are needed to further define the subset of patients who will benefit from postmastectomy radiation and to more precisely quantitate this benefit.