Long-term Results of Postoperative Prophylactic Nodal Irradiation for Node-Positive, High-Risk Breast Cancer Patients

OBJECTIVE: To retrospectively evaluate the long-term results of postoperativenodal irradiation. Patients: A total of 271 patients with breast cancer treated between 1976 and1993 were analyzed retrospectively. All patients underwent modified radical mastectomy and exhibited extensive axillary lymph node involvement. METHODS: Of 271 patients, 116 were non-randomly selected for postoperative irradiation (RT)of the internal mammary and supraclavicular nodes. Intensive chemotherapy (CT) such as cyclophosphamide, methotrexate, and 5-FU (CMF) was not used for adjuvant systemic therapy. Eight clinical and laboratory parameters were evaluated for their significance with regard to survival and local control at theirradiated area. Each factor was tested for significance with uni- and multivariate analysis. RESULTS: The minimum and median follow-up periods for survivors were 37 and 104 months, respectively. Ten-year cause-specific overall survival (OS), disease free survival (DFS), and local control within the irradiated field (LC) for the whole cohort were 51.9%, 33.0% and 78.8%, respectively. Multivariate analysis showed that the estrogen receptor status and the number of involved nodes were themost significant prognostic factors for both OS and DFS in this group of patients. Adding RT did not improve either OS or DFS. For local control, radiation therapy as well as estrogen receptor status were significant prognostic factors. CONCLUSION: Although postoperative nodal irradiation clearly reduced the incidence of local recurrence, it did not improve the survival of high risk patients. A clinical trial which combines an intensive CT and postoperative radiotherapyshould be undertaken.