Axillary node staging by ultrasonography and fine-needle aspiration cytology in patients with breast cancer

Background: This study evaluated the role of axillary ultrasonography (AUS) and fine-needle aspiration cytology (FNAC) in preoperative staging of the axilla in patients with invasive breast cancer. Methods: Between October 2006 and March 2009, 502 patients scheduled to undergo surgery for invasive breast cancer had preoperative AUS. All patients with suspicious nodes on ultrasonography underwent FNAC, and those with positive cytology proceeded directly to axillary node clearance. Patients with normal findings on AUS or negative cytology underwent sentinel node biopsy (SNB). Results: A total of 137 (27.3 per cent) of 502 patients had axillary node metastases on final histology. Thirty-nine (28.5 per cent) node-positive patients were identified by AUS-FNAC and spared unnecessary SNB. AUS-FNAC had a sensitivity of 28.5 per cent and a specificity of 100 per cent for detecting axillary nodal metastases. AUS-FNAC findings were normal in all 15 patients with nodal micrometastases and in 11 patients with isolated tumour cells on histopathology. The sensitivity of AUS-FNAC had a positive correlation with invasive tumour size (odds ratio 1.03) and grade (odds ratio 2.80). Conclusion: Preoperative AUS-FNAC avoided unnecessary SNB in 28.5 per cent of node-positive patients and in 7.8 per cent of patients overall.