Ultraschall Med 2013; 34 - WS_SL18_02
DOI: 10.1055/s-0033-1354913

Assessment of ultrasound features predicting axillary nodal metastasis in breast cancer

A Stachs 1, A Tra-Ha Thi 2, S Hartmann 2, J Stubert 2, T Reimer 2, B Gerber 2
  • 1University of Rostock, Department of Gynecology and Obstetrics, Rostock, Germany
  • 2University of Rostock, Rostock, Germany

Purpose: In preparation of a planned study to compare axillary sentinel lymph node biopsy (SLNB) versus no axillary surgery in patients with early breast cancer (Intergroup-Sentinel-Mamma-Trial) we evaluated the accuracy of axillary ultrasound (AUS) in detecting axillary nodal metastasis. The aim was to identify ultrasound features with high predictive power and to create a suitable clinical flow chart.

Material and methods: In this prospective study, 120 patients with primary diagnosis of breast cancer were included. AUS was performed using a 12 MHz linear-array tranducer before core needle biopsy and the following characteristics were evaluated: shape, ratio length/width, margins, cortical thickness, hyperechoic hilum. Results were correlated to histopathological nodal status after SLNB or axillary lymph node dissection (ALND).

Results: Nodal metastases were present in 55/120 patients (48.5%). Sensitivity, specifity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of AUS were 49.1%, 87.7%, 77.1%, 67.1% and 70.0%. By univariate analysis, absence of hyperechoic hilum, round shape, ratio length/width < 2, sharp margins and cortical thickness > 3 mm were associated with lymph node metastases. Multivariate logistic regression revealed hypoechoic hilum and cortical thickness > 3 mm as independent predictive parameters for nodal involvement. Hypoechoic hilum was observed in 28 of 55 patients with metastatic involved lymph nodes. Using cortical thickness, sensitivity increases to 69.1% with specificity decreasing to 70.8%.

Conclusion: Hypoechoic hilum and cortical thickness > 3 mm are strong predictors of nodal metastatic involvement. Adding fine needle aspiration (FNA) of sonographically suspicious lymph nodes improves specificity of the method. However, negative AUS does not exclude lymph node metastases. In future, the combination of tumorbiological findings and ultrasound characteristics may help to select breast cancer patients with low risk for nodal positive disease.