Role of axillary ultrasound in the evaluation of early breast cancer in the era of Z0011: Time to redefine?

Introduction: Ultrasound with concurrent histology of abnormal axillary lymph nodes has revolutionized the treatment of patients with breast cancer. By identifying nodal metastases, patients can avoid a two-stage axillary procedure. However, the results of the American College of Surgeons Oncology Group Z0011 trial indicate that a certain group of patients may have been over-treated with axillary dissection. Our aim was to analyze the nodal burden of patients identified by axillary ultrasound and to determine the proportion of patients who could have foregone axillary dissection incorporating Z0011 trial. Methods: A retrospective analysis of patients with diagnosed breast cancer who underwent direct axillary dissection was performed. Based on nodal metastases patients were categorized into ‘extensive’ and ‘minimal’ groups and studied. Demographics and tumor characteristics were analyzed and eligibility for the Z0011 study was determined. Results: All 1745 patients diagnosed with breast cancer underwent axillary ultrasound from April 2009 to March 2015. Of these, 197 patients had histology-proven nodal metastases and underwent direct axillary lymph node dissection. One hundred and twenty-one patients (61.4%) had extensive and 76 patients (38.6%) had minimal nodal metastases. Of the latter, 23 patients (11.7%) fulfilled the Z0011 criteria. Conclusion: This study demonstrated that a large proportion of patients had minimal nodal involvement (38.6%), in contrast to the results published in the literature. In addition, a significant number of patients could have avoided axillary dissection (11.7%) based on the Z0011 criteria. Hence our study encourages to redefine the role of axillary ultrasound to avoid unnecessary axillary dissection. Key points: Axillary ultrasound is performed in all patients diagnosed with breast cancer. Axillary ultrasound findings do not correlate with histological burden of nodal disease. Role of axillary ultrasound needs to be redefined to avoid unnecessary axillary dissection.