Axillary Management in Breast Cancer Patients with Positive Lymph Nodes Following Neoadjuvant Chemotherapy.

Abstract

Currently, patients with biopsy-proven axillary disease undergoing neoadjuvant chemotherapy (NAC) must undergo completion axillary lymph node dissection (cALND) if there is residual disease in the sentinel lymph nodes (SLN). In the era of axillary de-escalation, our objectives were to evaluate the frequency of involved non-SLN during cALND and whether clinical, radiologic, and pathologic characteristics can predict non-SLN involvement. This was a multicenter, retrospective cohort study of patients with biopsy proven node-positive breast cancer between 2012 and 2024, who had residual nodal metastases (ypN+) post NAC and underwent cALND following SLN biopsy (SLNB) or targeted axillary lymph node dissection (TAD). Patients were grouped by the presence or absence of positive non-SLN at cALND (cALND+ vs. cALND-). Descriptive statistics were used to compare demographic, radiologic and pathologic data between groups. Univariate and multivariate analyses were used to identify predictors of cALND+. Overall, 122 ypN+ patients were included in the study; 57 (46.7%) had cALND+. Predictors of cALND+ on multivariate analysis included the number of abnormal lymph nodes on pretreatment axillary ultrasound (odds ratio [OR] 3.74, 95% confidence interval [CI] 1.5-10, p = 0.006), SLN extracapsular extension on final pathology (OR 2.6, 95% CI 1.08-6.5, p = 0.036), lymphovascular invasion (OR 2.47, 95% CI 1.05-6.02, p = 0.041) and SLN ratio (positive SLNs/total SLNs excised) > 0.5 (OR 4.33, 95% CI 1.88-10.4, p < 0.001). This study proposes factors that predict cALND+ in initially node-positive patients who undergo NAC and have ypN+ disease on SLNB/TAD and identifies patients who should potentially be selected for cALND versus those who maybe be spared.