Strategies to Optimize Axillary Surgery in Patients With Breast Cancer Receiving Neoadjuvant Endocrine Therapy

Current guidelines for axillary surgery following systemic therapy do not differentiate between neoadjuvant endocrine therapy (NET) and neoadjuvant chemotherapy (NAC). Without specific guidelines, many assume that axillary surgery after NET should mirror that after NAC; however, NET has traditionally been used for patients with biologically favorable disease, so alternative axillary surgery strategies may be appropriate. Unfortunately, clinical trials that have examined NET have not rigorously studied axillary management or outcomes. The limited observational data available reveal that axillary lymph node dissection (ALND) is less frequently performed for positive nodes following NET than NAC; ALND rates after NET are more like those of upfront surgery patients. Although outcomes of omitting ALND after NET in patients who remain node positive are unknown, hypothesis-generating work from the National Cancer Database suggests that most patients selected for NET have limited nodal burden, and the prognostic significance of residual nodal disease after NET may not carry the same implications as residual disease after NAC. As such, there is opportunity to define axillary surgery strategies after NET that differ from those used after NAC.