The Role of Axillary Lymph Node Dissection versus Sentinel Lymph Node Dissection in Breast Cancer Patients with Clinical N2b-N3c Disease Who Receive Adjuvant Radiotherapy.

Abstract

For breast cancer with advanced regional lymph node involvement, axillary lymph node dissection (ALND) remains the standard of care for staging and treating the axilla despite the presence of undissected lymph nodes. The benefit of ALND in this setting is unknown. We sought to describe national patterns of care of axillary surgery and its association with overall survival (OS) among women with cN2b-N3c breast cancer who receive adjuvant radiotherapy. We identified female patients with cN2b-N3c breast cancer from 2012 to 2017 from the National Cancer Database. Clinical and demographic information were analyzed using Wilcoxon rank sum and χ2 tests. Predictors of receipt of ALND and predictors of death were identified with multivariable logistic regression modeling. Inverse probability of treatment weighting was implemented to adjust for differences in treatment cohorts. The Kaplan-Meier method was used to evaluate OS. We identified 7167 patients. Of these, 922 (13%) received SLNB and 6254 (87%) received ALND; 7% were cN2b, 19% cN3a, 24% cN3b, 19% cN3c, and 31% cN3, not otherwise specified. Predictors of receipt of ALND were age 50-69 years [odds ratio (OR) 1.3, p < 0.01], cN3a (OR 7.6, p < 0.01), cN3b (OR 2.8, p < 0.01), and cN3c (OR 4.2, p < 0.01). Predictors of death included cN3c (OR 1.9, p < 0.01), age 70-90 years (OR 1.5, p = 0.01), and positive surgical margins (OR 1.5, p < 0.01). After cohort balancing, ALND was not associated with improved OS when compared with SLNB (HR 0.99, p = 0.91). ALND in patients with advanced nodal disease was not associated with improved survival compared with SLNB for women who receive adjuvant radiotherapy.