Factors Predicting Additional Residual Nodal Disease With a Metastatic Sentinel Node Biopsy or Targeted Axillary Dissection After Neoadjuvant Chemotherapy.

Abstract

Purpose: This study aimed to investigate whether specific clinicopathological characteristics are associated with a lower likelihood of additional positive nodes (APNs) on completion axillary lymph node dissection (cALND).

Methods: A total of 497 patients with cT1-4/N1-3 disease underwent cALND following a positive sentinel lymph node biopsy (SLNB) or targeted axillary dissection (TAD) after neoadjuvant chemotherapy (NAC). The APN rate was assessed based on findings from the cALND.

Results: The median age was 47 (21-84). The overall APN rate was 67.6%. Patients with cT1-2 disease, a breast pathological complete response, removal of > two nodes via SLNB or TAD, only one metastatic node identified at SLNB or TAD, a lymph node ratio (LNR) < 50%, or low-volume metastatic disease (including isolated tumor cells [ITCs] or micro-metastases) at SLNB or TAD were significantly less likely to have APN on cALND (p < 0.05). Multivariate logistic regression analysis showed a decreased likelihood of APN on cALND in patients with cT1-2 disease (odds ratio [OR], 0.56; 95% confidence interval [CI], 0.35-0.89; p = 0.016), ITCs or micro-metastases (OR, 0.32; 95% CI, 0.12-0.84; p = 0.021), and an LNR < 50% at SLNB or TAD (OR, 0.22; 95% CI, 0.14-0.37; p < 0.001). Among subgroups, patients with cT1-2/N1 disease and either LNR < 50% or ITC/micro-metastasis, as well as patients with cT1-3 cN1 disease undergoing TAD with LNR < 50%, had APN rates on cALND of 23.4%, 26.7%, and 16.7%, respectively.

Conclusion: In patients with a positive SLNB or TAD after NAC, an APN rate < 30% on cALND can be achieved in certain subgroups with favorable features, including cT1-2 and cN1 disease and low-volume metastatic burden.