Factors Associated With Residual Positive Lymph Nodes With Targeted Axillary Lymph Node Dissection for Breast Cancer and Accuracy of Clipped Node Retrieval in Non-Mapping Patients.

Background: The current study aimed to determine whether results could justify whether axillary lymph node dissection (ALND) could be further de-escalated in selected patients having neoadjuvant chemotherapy (NAC).

Methods: Retrospective analyses were performed for breast cancer patients treated with NAC from 2015 to 2023. Abnormal axillary nodes evaluated by pretreatment ultrasound had core biopsies with microclip placement. Patients assigned to ALND had histologically positive SLND (ypN+), were clinically node-positive (ycN+) post-NAC, did not map, or did not have a clipped node retrieved.

Results: There were 274 predominantly Hispanic (78%) patients, the median age was 51 years, and the follow-up was 38.1 months. Of 198 pN+ patients, 120 were clinically node-negative (ycN0) post-NAC and had wire-directed (WD) SLND, whereas 78 were ycN+ and had planned ALND. Sixty percent of pN+ patients converted to ypN0 post-NAC. Fifty-eight percent of patients with ypN+ status had additional positive non-sentinel lymph nodes in the ALND specimen.

Conclusions: ALND was avoided in approximately half of patients who presented with axillary node metastases and became ycN0 post-NAC. Response to NAC correlated with node status at surgery. Patients who do not map may not need ALND if a pN+ clipped node is retrieved and converts to ypN0.