Patterns of Axillary Management in Stages 2 and 3 Hormone Receptor-Positive Breast Cancer by Initial Treatment Approach.

Abstract

Data regarding axillary management after neoadjuvant endocrine therapy (NET) are lacking. This study examined axillary management of hormone receptor-positive (HR+) patients based on initial treatment with NET, neoadjuvant chemotherapy (NAC), or upfront surgery. Patients with stage 2 or 3 HR+/HER2- breast cancer treated between 2012 and 2015 were identified in the National Cancer Database. The study examined axillary surgery [sentinel lymph node biopsy (SLNB), SLNB followed by axillary lymph node dissection (ALND), or upfront ALND] by initial treatment stratified by cN0/N1 using pairwise comparisons and multivariable logistic regression. Of 92,204 eligible patients, 2138 (2.3%) received NET, 11,014 (12%) received NAC, and 79,052 (85.7%) received surgery. Among 60,998 cN0 patients, attempted SLNB was more likely for surgery patients (86.2%, 47,159/54,684) and NET patients (85.8%, 1342/1564) than for NAC patients (79.9%, 3793/4750) (both p < 0.001). Among 31,206 cN1 patients, attempted SLNB was more likely for the surgery patients (46.0%, 11,201/24,368) than for the NET patients (41.8%, 240/574; p = 0.05) or the NAC patients (39.8%, 2491/6264; p < 0.0001). The differences between surgery and NET did not persist in the adjusted analyses. Among both the cN0 patients (n = 13,856) and the cN1 patients (n = 8688) with pN1 disease shown by SLNB, the NET patients were treated with ALND less frequently than those receiving NAC or surgery (p < 0.0001 for all comparisons). In the multivariate analysis, for the patients with pN1 disease shown by SLNB, NET use was associated with increased odds of undergoing SLNB alone [cN0 patients: odds ratio (OR), 1.31, 95% confidence interval (CI), 1.04-1.64; cN1 patients: OR 1.45; 95% CI 1.00-2.10]. For stages 2 and 3 HR+/HER2- patients, SLNB use after NET was similar to that for upfront surgery. Among those with pN1 disease, the NET patients were less likely to undergo ALND. Additional outcomes data are needed to guide axillary management after NET.