Ultrasound staging in breast cancer: A decision-making oriented approach to axillary metastatic burden prediction

The possibility of avoiding axillary lymphadenectomy (AL) in patients with breast cancer (BC) after positive sentinel lymph node biopsy (SLNB) and low metastatic burden (< ó = 2 positive lymph nodes) has put into question the role of axillary ultrasound due to the risk of overtreatment after positive axillary lymph node biopsy with low metastatic burden. Our aim was to identify clinical and ultrasound features to detect low and high metastatic burden.

A retrospective study of 405 BC patients with primary surgical treatment with axillary ultrasound examination and subsequent AL after positive fine needle aspiration (FNA) or SLNB. The low and high tumor burdens after AL were correlated with clinical and ultrasound variables: lymph node morphology (UN1 to UN5), number of suspicious lymph nodes, and Berg level.

Positive FNA, lymph node morphology UN4 (focal thickening with displacement of the fatty hilum) or UN5 (complete replacement of the fatty hilum) and >2 suspicious lymph nodes were significantly associated with "high metastatic burden". Lymph node morphology UN2 and UN3, even after FNA+, lymph node morphology UN4 after FNA-, and suspicious lymph nodes at Berg level I were low metastatic burden criteria. Lymph node morphology UN5, lymph node morphology UN4 after FNA+, two nodes or more with UN4/UN5 morphology, and suspicious lymph nodes at Berg levels II and III with FNA+ were associated with high metastatic burden.

Axillary lymph node ultrasound data for patients with early BC allows predicting the axillary metastatic burden, guiding the optimal clinical management of the axilla.