Pre-operative axillary ultrasound with fine-needle aspiration cytology performance and predictive factors of false negatives in axillary lymph node involvement in early breast cancer

Purpose: Breast cancer is the most common cancer among females worldwide. Axillary lymph node involvement is an important prognostic factor in pre-operative evaluation. The aim of this study was to evaluate the sensitivity and accuracy of AUS during the initial breast cancer diagnosis and the contribution of ultrasound with guided FNAC (AUS + FNAC) in cases of suspicious node.

Methods: A retrospective study was conducted at the Lorraine Cancer Institute between 1 January and 31 December 2015. It included patients with early breast cancer, all of whom received AUS. If axillary node involvement was suspected, FNAC was performed. Sentinel lymph node biopsy (SLNB) and/or axillary lymph node dissection (ALND) were performed depending on FNAC results.

Results: In total, 292 patients were included. 88 patients (30.1%) had a suspicious lymph node on ultrasound and had FNAC, of whom 53 tested positive for axillary node involvement (60.2%). Among the 35 patients who tested negative with FNAC, 15 had axillary metastatic involvement. Performance of AUS + FNAC was better than that of AUS alone, with sensitivity, specificity, positive predictive and negative predictive values of approximately 44.5%, 100%, 100% and 72.4%, respectively, and accuracy of approximately 77.4%. Luminal A subgroup, axillary involvement of less than two positive nodes or nodal tumor of less than 7 mm are independent factors of false negative rate.

Conclusions: AUS performance would seem to be improved by FNAC, with a false negative rate of approximately 26%. It may be possible to reduce the false negative rate of AUS if its contributing factors are taken into consideration, along with the impact of specific echographic signs as revealed by experienced radiologists.