Targeted axillary dissection after neoadjuvant chemotherapy in breast cancer patients with a high lymph node burden: Radiological and histological outcomes

Abstract

Introduction: Axillary surgery in early breast cancer has evolved towards de-escalation, particularly for patients receiving neoadjuvant systemic therapy (NACT). Targeted axillary dissection (TAD), combining sentinel lymph node biopsy (SLNB) with excision of a clipped metastatic node, reduces false-negative rates and may allow omission of axillary lymph node dissection (ALND). However, evidence for its safety in patients with high lymph node burden (HLNB, ≥4 abnormal nodes) remains limited.

Methods: This retrospective study included women treated with TAD following NACT at The Royal Marsden NHS Foundation Trust (2018-2023). Patients were stratified by baseline nodal burden into low (LLNB, 1-3 nodes) and high (HLNB, ≥4 nodes) groups. Data on clinicopathological features, imaging-pathology concordance, surgical outcomes and oncological follow-up were analysed.

Results: Among 179 women (139 LLNB, 40 HLNB), HER2-positive and triple-negative subtypes were more frequent in the HLNB group. The clipped node contained a Magseed in 83.8 % of cases and was also a sentinel node in 71.3 %. Axillary pathological complete response (pCR) was achieved in 110/179 (61.4 %) patients - 61.2 % LLNB vs 62.5 % HLNB (p = 1.0). Of those with axillary pCR, 98.2 % avoided axillary lymph node dissection (ALND). End-of-treatment axillary ultrasound had a positive predictive value of 56.6 % and negative predictive value of 74.8 % for residual disease. At a median follow-up of 30 months, no axillary recurrences occurred; disease-free survival was comparable between groups (p = 0.32), with a non-significant trend toward poorer overall survival in HLNB (p = 0.055).

Conclusions: TAD after NACT appears oncologically safe in selected patients with both low and high nodal burden, enabling omission of ALND in most cases. Prospective studies are warranted to confirm its role in HLNB disease.

Keywords: Axillary surgery; Breast cancer; High lymph node burden; Magseed; Neoadjuvant chemotherapy; Targeted axillary dissection.