The role of ultrasound guided core biopsy of axillary nodes in predicting macrometastases and avoiding overtreatment outside ACOSOG Z0011 parameters

Background: Z0011 study suggests patients with minimal disease do not require axillary clearance. Exclusions include T3 tumours, mastectomy or neoadjuvant treatment. This study assessed the utility of pre-operative US-guided core biopsy of axillary nodes and its correlation with nodal macrometastases. Methods: 247 women with breast cancer outside Z0011 criteria were reviewed retrospectively. Sensitivity and specificity of pre-operative axillary ultrasound and core biopsy compared to final histology was assessed by contingency tables. Results: 75/247 patients had macrometastases. Ultrasound-axilla was 72% sensitive and 77% specific in predicting macrometastasis. The positive (PPV) and negative predictive value (NPV) was 58% and 86.4% respectively. Core-biopsy of axilla node, was 92.6% sensitive and 66.7% specific in detecting macrometastasis. PPV and NPV 79.4% and 86.7% respectively. Conclusion: Positive pre-operative ultrasound-guided core biopsy accurately predicts macroscopic involvement of axillary nodes. Selected patients outside Z0011 parameters can proceed to axillary clearance without sentinel node biopsy or risking overtreatment.