Predicting Axillary Lymph Node Status Using Preoperative Ultrasound-Guided Fine Needle Aspiration Cytology of Radiologically Equivocal and Abnormal Nodes.

Abstract

Abstract Introduction:The superiority of ultrasound (US) over clinical examination in the assessment of axillary nodes in patients with breast carcinoma is well recognised. Fine needle aspiration cytology (FNAC) is a quick and minimally invasive procedure to determine the status of axillary lymph nodes pre-operatively. Sentinel lymph node biopsy (SLNB) is now widely accepted as the primary axillary staging procedure in the management of early breast cancer. A negative SLNB obviates the need for more extensive axillary surgery, thereby reducing the morbidity associated with axillary node clearance (ANC) in patients with node negative breast cancer. Patients with a SLNB positive for metastasis usually require further axillary treatment, which may include completion ANC and/or radiotherapy. Improving the accuracy of pre-operative staging is desirable in reducing the number of completion ANC procedures necessitated following positive SLNB. The aim of this study is to assess the accuracy of pre-operative US-guided FNAC of radiologically equivocal or abnormal axillary lymph nodes.Method:Patients with a diagnosis of invasive breast carcinoma underwent axillary US. Those with radiologically equivocal or abnormal nodes had US-guided FNAC. Patients with a metastatic FNAC had ANC, whereas those with insufficient (i.e. no lymphocytes seen on cytology), benign or equivocal FNAC had SLNB.Results:Correlation of FNAC result and final histologyFNAC ResultN=59Node positivity N=42Inadequate54Benign173Equivocal10Suspicious11Malignant3534 The positive predictive value of suspicious or malignant cytology from a radiologically equivocal or abnormal node is 97%. The negative predictive value is 70%. US-guided FNAC used in the context has 83% sensitivity and 94% specificity.Of the five patients with radiologically equivocal or abnormal nodes and an inadequate cytology (no lymphocytes seen), four had a metastatic sentinel node biopsy.One patient had a malignant FNAC prior to neoadjuvant chemotherapy (NACT) and had benign histology on subsequent ANC. If this patient is excluded from analysis, the positive predictive value rises to 100%.Conclusion:US-guided FNAC of radiologically equivocal or abnormal axillary lymph nodes accurately predicts node positivity and can be used to avoid an unnecessary SLNB procedure.Inadequate FNAC from an equivocal or abnormal node is not sufficient evidence to recommend SLNB rather than ANC as the initial surgical axillary procedure. Patients with such findings should have a repeat US-guided FNAC before choosing to proceed with SLNB. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 1031.