The Impact of Neoadjuvant Chemotherapy on Axillary Surgical Management of Patients With Breast Cancer and Positive Axillary Lymph Nodes

Background/aim: Sentinel lymph node biopsy (SLNB) is effective in patients with breast cancer (BC) and positive axillary lymph nodes undergoing neoadjuvant chemotherapy (NAC). However, the frequency with which axillary lymphadenectomy (ALND) can be avoided remains debated. This study aimed to identify patient populations that can benefit from this approach.

Patients and methods: The data of 195 consecutive patients with BC and positive axillary lymph nodes at diagnosis who underwent NAC were retrospectively analyzed. In all cases, the positivity of the lymph nodes was confirmed by cytological examination. Patients converted to ycN0 after NAC were considered eligible for SLNB. Indications for ALND were failed mapping, fewer than three SLNs recovered, and positive SLNs.

Results: Of 195 cN1 patients potentially eligible for SLNB, 71 (36.4%) remained clinically ycN+ after NAC and underwent elective ALND, while 124 (83.7%) converted to ycN0 after NAC and SLNB. The lymph node identification rate was 95.9% (119/124 patients) with three or more SLNs recovered in 83 cases (89.8%). One or two lymph nodes were recovered in 36 cases (30.2%). Nodal pathologic complete response (pCR) was found in 34/83 (40.9%) patients with three or more SLNs recovered. Considering all 195 patients initially included in the study, 55 patients (28.2%) achieved lymph node pCR after NAC. Nodal pCR varied based on hormone receptor and HER2 status, with rates ranging from 20.7% for ER+/HER2- patients to 95.3% for ER-/HER2+ patients (p<0.001).

Conclusion: More than 80% of cN1 patients in our study were eligible for SLNB after NAC. ALND could be avoided in approximately 30% of cases, supporting the role of NAC in reducing the need for ALND among patients with lymph node metastases.