Axillary lymph node status in breast cancer staging: What patient and tumor factors affect the accuracy of ultrasound-guided fine needle aspiration?

Abstract

1126 Background: The purpose of the study is to evaluate the accuracy of ultrasound-guided fine needle aspiration (FNA) of axillary lymph nodes(ALNs) in patients with breast cancer and to determine factors that influence accuracy of ultrasound-guided FNA. Methods: Retrospective review of patients with breast cancer who had FNA of ALNs as well as sentinel lymph node excision or complete axillary dissection. Patients treated with neoadjuvant chemotherapy were excluded. 55 axillary FNAs in 54 patients were included in the final analysis. Pathology reports were reviewed for size of the primary tumor, FNA results, number of positive ALNs, and greatest tumor size in ALNs. FNA was performed if a suspicious lymph node was identified. Surgical sentinel lymph node biopsy or full axillary dissection were the reference standard. Micrometastases (< 0.2 mm) and isolated tumor cells in the lymph node were included in the negative group. Atypical and nondiagnostic FNA results were considered negative cytologic results. Significance was analyzed using the Mann-Whitney test. Results: Size of the primary cancer ranged from 0.3 mm to 8.5 cm. The sensitivity of FNA was 73%, with positive predictive value of 97% and negative predictive value of 52%. The NPV of FNA for primary tumors <1 cm, 1.1-2, 2.1-5 and >5 cm is 100%, 36%, 50% and 66% respectively. Correlation of primary tumor size with sensitivity of FNA was not statistically significant. The sensitivity of FNA for lymph nodes with metastatic deposit < 5mm, 6-10mm, 11-15mm, 16-20mm, and 21mm+ is 0%, 57%, 59%, 89%, and 100%, which is statistically significant (p = 0.007). The number of positive ALNs at axillary dissection is not correlated to the sensitivity of FNA. The sensitivity of FNA for 1-3, 4-9 and 10+ positive ALNs is 78%, 64% and 80%. Conclusions: Our findings indicate that FNA of suspicious axillary lymph nodes is valuable even in small tumors, which differs from the literature. The overall negative predictive value of FNA is 52%, so sentinel lymph node biopsy is essential after negative FNA. Sensitivity of FNA increases with the size of the metastatic deposit in the lymph node, but is not correlated to the number of positive ALNs found at dissection.