Are Lymph Node Characteristics on Axillary Ultrasound Associated with ≥3 Positive Lymph Nodes in Patients Managed by the American College of Surgeons Oncology Group Z0011 Trial Criteria?

Patients often receive axillary ultrasound-biopsy (AUS-B) before clinical evaluation. One positive biopsy in the absence of palpable disease rarely indicates additional nodal involvement, but it eliminates patients from being managed by the American College of Surgeons Oncology Group Z0011 trial criteria. To determine which patients may benefit from AUS-B, we analyzed whether characteristics on AUS were associated with large-volume axillary disease and, thus, the need for axillary lymph node (LN) dissection. A retrospective review identified patients who met Z0011 criteria and underwent AUS. Clinicopathologic and ultrasound characteristics were compared between patients with ≤2 versus ≥3 positive LNs. Two hundred and seven patients with cT1-2N0 tumors underwent preoperative AUS and breast-conserving surgery. On multivariate analysis, three AUS combinations were associated with ≥3 positive LNs: cortical thickness (CT) > 4 mm + loss of fatty hilum + round shape (P = 0.0218), CT > 4 mm + loss of fatty hilum (P = 0.0211), and CT > 4 mm + round shape (P = 0.0155). Preoperative axillary LN biopsy in patients with a single abnormal LN characteristic on AUS may be unnecessary because a positive finding will eliminate management according to Z0011 criteria. Cortical thickness >4 mm combined with any other abnormal characteristic was associated with ≥3 positive LNs, supporting the performance of AUS-B in this population.