Application of the Z1071 criteria: classification of axillary lymph nodes on ultrasound after neoadjuvant chemotherapy in initially node-positive breast cancer.

Abstract

The American College of Surgeons Oncology Group (ACOSOG) Z1071 trial assessed the accuracy of sentinel lymph node biopsies in clinically node-positive patients who underwent neoadjuvant chemotherapy (NAC). Axillary ultrasound (US) images after NAC were reviewed, and the accuracy of classifying nodes into six types according to the ACOSOG Z1071 trial was determined. This study included 69 patients who underwent NAC followed by curative surgery for breast cancer including axillary lymph node dissection between January 2010 and July 2019. All patients were pathologically confirmed as being initially node positive. Lymph nodes were retrospectively classified into one of six types based on the appearance of the nodal cortex and hilum. Types I and II were classified as having normal nodal morphology, whereas types III, IV, V, and VI were classified as having suspicious nodal morphology. These node types on US images after NAC were compared between patients with an axillary complete response (Ax-pCR) and those with residual metastatic lymph nodes (Ax-non-pCR) using Chi-square tests. Twenty-four (35%) of the 69 patients achieved Ax-pCR. Patients with nodes classified as type I or II were more likely to achieve Ax-pCR (83% vs. 36%, p = 0. 0002). The classification of six node types was associated with nodal status.