Initial axillary staging of breast cancer using ultrasound-guided fine needle aspiration: a liquid-based cytology study.

Objective: To evaluate the preoperative detection of axillary metastasis combining ultrasound (US)-guided fine needle aspiration cytology (FNAC) and liquid-based cytology (Surepath (R)) to reduce sentinel node procedures. Methods: In total, 148 patients with clinically negative lymph nodes and no preoperative therapy were included. All patients underwent preoperative ultrasound of the axilla with FNAC if suspicious lymph nodes were found. Complete axillary lymph node dissection was performed at primary surgery when FNAC was positive. All other patients underwent a sentinel node procedure. Results: US-guided FNAC of the axilla revealed metastasis in 34 (23.0%) of the 148 patients. These 34 patients were 53.1% of all patients (n = 64) with proven axillary lymph node involvement. In 66 patients (44.6%), both ultrasound and histopathology were negative. Overall sensitivity of US-guided FNAC was 50.0%, specificity 100%, positive predictive value 100% and negative predictive value 70.2%. In T1 tumours, all patients referred for sentinel node procedure were node-negative. The correlation between malignant FNAC and histopathology was 100%. US-guided liquid-based FNAC in patients with no clinically positive lymph nodes reduced the necessity for a sentinel node procedure by 23.0%. Conclusions: We advocate that US-guided fine needle aspiration (FNA) combined with liquid-based cytology of axillary lymph nodes should be included in the preoperative staging of breast cancer.