The role of postoperative irradiation in carcinoma of the breast.

Chest wall and regional nodal recurrences, and survival following postmastectomy radiation therapy, were analyzed in 352 patients. Patients with T1 and T2 central and medial breast lesions, negative axillary nodal findings, and no evidence of skin or chest wall extension received irradiation to the peripheral lymphatics alone. There were no chest wall recurrences among these patients. The remainder of the patients, including those with axillary nodal involvement, regardless of the site of the primary breast lesion received irradiation by a three-field technique directed to both chest wall and regional nodes. The chest wall recurrence rate was 1.9% when axillary nodes were negative for metastatic disease, 1.3% when the axillary nodes showed less than 50% positivity, and 14.2% when axillary nodes showed greater than 50% involvement. The overall chest wall recurrence rate was 5.1%. A possible mechanism of chest wall recurrence is discussed. Cumulative 5-year survival for stage I is 76%, for stage II, 79%, and for stage III, 57%. If chemotherapy proves to be effective in controlling distant microscopic disease local control may become an equally critical issue in long-term survival of patients with breast carcinoma.