Axillary Ultrasound and Fine-needle Aspiration in the Preoperative Evaluation of the Breast Cancer Patient: an Algorithm Based on Tumor Size and Lymph Node Appearance

Objective: The objective of our study was to evaluate the utility of ultrasound-guided fine-needle aspiration (FNA) of the axillary lymph nodes in breast cancer patients depending on the size of the primary tumor and the appearance of the lymph nodes.

Subjects And Methods: Data were collected about tumor size, lymph node appearance, and the results of ultrasound-guided FNA and axillary surgery of 224 patients with breast cancer undergoing 226 ultrasound-guided FNA. Lymph nodes were classified as benign if the cortex was even and measured < 3 mm, indeterminate if the cortex was even but measured ≥ 3 mm or measured < 3 mm but was focally thickened, and suspicious if the cortex was focally thickened and measured ≥ 3 mm or the fatty hilum was absent. The results of ultrasound-guided FNAs were analyzed by the sonographic appearance of the axillary lymph nodes and by the size of the primary tumor. The sensitivity and specificity of ultrasound-guided FNA were calculated with axillary surgery as the reference standard. The sensitivity and specificity of axillary ultrasound to predict the ultrasound-guided FNA result were calculated.

Results: Of the 224 patients, 51 patients (23%) had a positive ultrasound-guided FNA result, which yields an overall sensitivity of 59% and specificity of 100%. The sensitivity of ultrasound-guided FNA was 29% in patients with primary tumors ≤ 1 cm, 50% in patients with tumors > 1 to ≤ 2 cm, 69% in patients with tumors > 2 to ≤ 5 cm, and 100% in patients with tumors > 5 cm. The sensitivity of ultrasound-guided FNA in patients with normal-appearing lymph nodes was 11%; indeterminate lymph nodes, 44%; and suspicious lymph nodes, 93%. Sonographic characterization of lymph nodes as suspicious or indeterminate was 94% sensitive and 72% specific in predicting positive findings at ultrasound-guided FNA.

Conclusion: Ultrasound-guided FNA of the axillary lymph nodes is most useful in the preoperative assessment of patients with large tumors (> 2 cm) or lymph nodes that appear abnormal.