Histopathological and Tumor Characteristics Associated with False Negative Axillary Ultrasonography Results in Breast Cancer

Aims: As the false-negative rates of axillary ultrasonography (AUS) (21%-48%) are not optimal, the demand for axillary surgery remains even if AUS is negative. The aim of this study is to determine the histopathological and tumor characteristics associated with false-negative AUS results. Materials and methods: Patients with normal AUS were divided into two groups as true-negative and false-negative according to the histopathology results of axillary lymph nodes. Two groups were compared in terms of age, histological grade of the primary tumor, histological size of the primary tumor, histological type, lymphovascular invasion (LVI), and ultrasonography BI-RATS classification of the primary tumor. The number of metastatic lymph nodes, size of the largest metastatic lymph node and the number of micrometastatic lymph nodes were also noted in the false-negative group. Results: There were 152 patients with normal preoperative AUS in the study group. The false-negative AUS rate was 20.4%. The incidence of invasive lobular carcinoma (ILC) and the mean tumor size was significantly-greater in the false-negative group. Micrometastasis was present in 3 patients (3/31, 9.6%), the mean of the largest metastatic lymph nodes was 12.5 mm, the mean total number of malignant lymph nodes was 1.9 in the false-negative group. In 25/31 (80.6%) of the patients, there were less than or equal to 2 metastatic lymph nodes. The presence of WI was higher in the false-negative group. There was no significant difference between the groups in terms of the other parameters. Conclusion: Before stating that the axilla is normal on ultrasonography, a careful evaluation should be made in patients with a mass >2 cm in size and/or ILC diagnosis.