H. Carisa Le-Petross MD, Presenter: Nothing to Disclose

Linda M. McCall MS, Abstract Co-Author: Nothing to Disclose

Kelly K. Hunt MD, Abstract Co-Author: Nothing to Disclose

Elizabeth Mittendorf MD, Abstract Co-Author: Nothing to Disclose

Gretchen M. Ahrendt MD, Abstract Co-Author: Nothing to Disclose

Lee G. Wilke MD, Abstract Co-Author: Nothing to Disclose

Karla Ballman PhD, Abstract Co-Author: Nothing to Disclose

Judy Boughey MD, Abstract Co-Author: Nothing to Disclose

ACOSOG Z1071 was a prospective multicenter trial evaluating axillary surgery in patients with biopsy proven node positive breast cancer (T0-4, N1-2, M0) receiving neoadjuvant chemotherapy (NAC). The role of post chemotherapy/preoperative axillary ultrasound (AUS) to assess for residual nodal disease remains unclear. Here we report the correlation of lymph node (LN) features on AUS after NAC with final nodal pathology. 

All patients had AUS performed after NAC (within 4 weeks prior to axillary surgery). AUS images were centrally reviewed for LN cortical thickness (in mm), LN size, and cortical morphologic features defined as: type I- no visible cortex, type II- < 3 mm hypoechoic cortex, type III- > 3mm hypoechoic cortex, type IV- generalized lobulated hypoechoic cortex, type V- focal hypoechoic cortical lobulation, and type VI- totally hypoechoic node with no hilum. We compared LN features on AUS after NAC with final nodal pathology. 

Surgical pathology and post NAC AUS images were available on 611(87.2%) patients. Median age was 50 years (range 23-93 years). 370 patients (60.6%) had residual nodal disease (N+) on final pathology and 241 (39.4%) had a complete pathologic nodal response (N0). The cortical thickness correlated with residual nodal response (mean 3.6mm vs. 2.5mm; p <0.0001). Neither LN size (p=0.40) nor long-axis diameter to short-axis-diameter ratio (LSR) (p=0.39) was significantly different between patients with pathological N+ vs N0 cases. Cortical morphologic type I and II had the lowest risk of residual nodal disease while type VI had the highest (p = 0.0002). The visualization of a fatty hilum in a lymph node was associated with response to chemotherapy or N0 disease (p = 0.0007).  

AUS after NAC is useful to assess for nodal response to NAC, with cortical thickness being the best predictor of residual nodal metastasis. LN size or LSR do not reliably exclude residual nodal metastasis in patients after NAC.

Cortical thickness of axillary LN can be used instead of LN size to differentiate post-NAC responders from non-responders and may help triage patients who would be eligible for SLNB instead of ALND.

Le-Petross, H, McCall, L, Hunt, K, Mittendorf, E, Ahrendt, G, Wilke, L, Ballman, K, Boughey, J, Correlation of Axillary Ultrasound Features after Neoadjuvant Chemotherapy with Final Pathology in Patients Presenting with Node-Positive Breast Cancer (T0-T4, N1-2, M0): Results from a Multi-institutional Collaborative Clinical Trial (Alliance).  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14008045.html