The Efficacy of Axillary Ultrasound in the Detection of Nodal Metastasis in Breast Cancer

Abstract

Recent reports indicate a lack of survival benefit for axillary lymph node dissection (ALND) versus sentinel lymph node biopsy in early breast cancer. To study this issue further, we assessed the accuracy and effectiveness of ultrasound examination in detecting axillary nodal involvement in breast cancer patients with the aim of refining our current clinical pathways. Ultrasound data were collected from breast cancer cases over 3 years. Images were reviewed by experienced radiologists and the following characteristics were assessed: size, morphology, hyperechoic hilum, and cortical thickness of the ipsilateral axillary nodes. The findings were correlated with histologic outcomes after ALND. Two hundred twenty-four cases were included in the analysis, 113 (50.4%) of which had evidence of metastatic nodal involvement at final histology. Of these 113 cases, ultrasound findings for 59 (52.2%) were positive. The overall positive predictive value of ultrasound for detecting metastatic nodal involvement measured 0.81. The negative predictive value was 0.60. The sensitivity was 53.7%; specificity, 85.1%; and accuracy, 67.9%. The ultrasound morphologic lymph node features with the greatest correlation with malignancy were the absence of a hyperechoic hilum (p = 0.003) and increased cortical thickness (p = 0.03). Patients with a metastatic nodal burden density of at least 20% were more likely to have abnormal findings on axillary ultrasound examination (p = 0.009). Axillary ultrasound has a low negative predictive value and negative ultrasound results do not exclude axillary node metastases with sufficient sensitivity to justify its routine clinical use. Clinical pathways need to consider an evidence-based approach, focusing on the criteria by which we select breast cancer patients for ALND.