The changing field of locoregional treatment for breast cancer.

The change to less-morbid local therapy for operable breast cancer continues. Systemic induction therapy, whether hormonal therapy or chemotherapy, increases the eligibility for breast-conserving surgery. Sentinel lymph node biopsy (SLNB) has greatly reduced the requirement for axillary dissection, and recent data show that, in addition, whole-breast irradiation can obviate the need for dissection in most patients with clinically node-negative, SLN-positive disease. Although resection margins must be negative for best results, there is no clear evidence that margins exceeding "no ink on tumor" for invasive cancer, or 2 mm for ductal carcinoma in situ, are significantly better. The role of radiation has been clarified, with a clear survival advantage for patients with node-positive disease; however, hypofractionation, which permits a briefer period of treatment, and accelerated partial breast irradiation (APBI) show promise of even further reductions in treatment--although late results for APBI are still needed. Elderly patients (> 70 years) with node-negative disease and estrogen receptor-positive tumors who have been treated with hormonal therapy can avoid primary breast irradiation without significant risk of ultimate breast loss or inferior survival.