Impact of locoregional radiotherapy in node-positive patients treated by breast-conservative treatment.

Abstract

The aim of this study is to evaluate the impact of locoregional radiation in node-positive patients treated by tumorectomy and radiation therapy. A retrospective study including all our 1368 T1-2 node-positive patients was conducted. Conservative surgery was followed by breast irradiation. Axillary and supraclavicular irradiation was left to the discretion of the treating radiation oncologist. In the group receiving locoregional radiation (472 patients), the 10-year regional control was 97% vs. 91% for the group receiving radiation to the breast only (896 patients) (p = 0.004). In a Cox model analysis, locoregional radiation is associated with a better regional control rate (hazard ratio: 0.27; 95% confidence interval: 0.13-0.54, p = 0.0001). Locoregional radiotherapy is associated with a better rate of locoregional control (hazard ratio: 0.56; 95% confidence interval: 0.38-0.8, p = 0.002). In particular, for the N>3 group, the substantial 10-year locoregional failure rate (26% with breast irradiation only) is cut by 50%. Locoregional radiotherapy, however, is not associated with a lower rate of distant metastases. Locoregional radiation decreases the rate of locoregional failure by nearly 50%. Locoregional radiotherapy should be considered for node-positive patients, especially if they have more than 3 positive nodes.