Long-term follow-up of patients in the National Surgical Adjuvant Breast Project protocol B-06 indicated that postoperative radiotherapy is effective in reducing local recurrence rates to less than 10%. Although some recurrences represent persistence of residual disease, a second type--a local manifestation of disseminated disease--presents as an extensive process involving several quadrants of the breast and extending to adjacent skin and chest wall. The first type is amenable to salvage therapy by either lumpectomy or mastectomy, depending on the clinical situation; the second type represents surgically inoperable disease and requires systemic therapy.