Axillary de-escalation after neoadjuvant chemotherapy for advanced lymph node involvement in breast cancer.

ABSTRACT

INTRODUCTION: Sentinel lymph node biopsy reduces morbidity in patients with clinically node-positive breast cancer who achieve axillary pathologic complete response following neoadjuvant therapy (NACT). De-escalation trials primarily addressed cN1 disease, with underrepresentation of cN2 disease. This study evaluates the role of de-escalation in patients with cN2 breast cancer. METHODS: A retrospective analysis of the National Cancer Database (2013-2020) included women over 18 with T1-2 invasive breast cancer and clinical N2 disease who received NACT followed by ALND or SLNB then ALND. The primary outcome was pathologic nodal status post-NACT. RESULTS: Of 5852 cN2 patients treated, 18.15 â€‹% achieved ypN0, 0.97 â€‹% had isolated tumor cells, 19.14 â€‹% were ypN1, 49.64 â€‹% were ypN2, and 12.20 â€‹% were ypN3 following NACT. Achieving ypN0 was associated with pCR in the breast, HER2-positive and triple-negative receptor status, cT2 tumors, and younger age. CONCLUSION: Despite some patients with cN2 disease achieving ypN0, most exhibited residual axillary disease post-NACT. These findings indicate that axillary de-escalation may not be feasible for most patients with cN2 disease, underscoring the importance of meticulous patient selection and assessment.