Node Positivity Among Sonographically Suspicious but FNA-Negative Axillary Nodes

Background: Fine needle aspiration (FNA) of sonographically suspicious axillary lymph nodes is helpful to clinically stage patients and guide consideration of neoadjuvant therapy in breast cancer. However, data are limited for suspicious nodes that are FNA negative. Our goal is to compare the frequency of node positivity between patients with negative axillary ultrasound (AUSneg) versus suspicious AUS with negative FNA (FNAneg). Methods: With IRB approval, we identified all clinically node-negative (cN0) patients with invasive breast cancer treated with upfront surgery at our tertiary care center between 2016 and 2021. AUS is routinely performed with FNA of suspicious lymph node(s). We compared clinicopathologic characteristics and nodal positivity rates between AUSneg and FNAneg groups. Results: A total of 1580 cN0 patients with invasive breast cancer were analyzed, including 1240 AUSneg and 340 FNAneg patients. The FNAneg group was younger (median age 59.7 years versus 63.5 years, p < 0.001) and had higher clinical T (cT) category (29.1% versus 21.7% with cT2–cT4 disease, p = 0.005). Final axillary pathologic node positivity did not differ significantly between the AUSneg and FNAneg groups (16.5% versus 19.1%, p = 0.25). Among FNAneg patients, 58/340 (17.1%) had a clip placed, with retrieval confirmed in 28/58 (48.3%). Of the 28 retrieved clipped nodes, 27 were sentinel nodes. Final pathologic nodal status (pN+%) did not differ between patients in whom retrieval of the clipped node was confirmed versus not confirmed (28.6% versus 16.7%, p = 0.28). Conclusions: Both patients with sonographically suspicious node(s) and negative FNA and patients with negative AUS have a similarly low chance of positive nodes. Additionally, routine targeted excision of FNA-negative clipped nodes is not warranted.