Preoperative Axillary Nodal Burden in Early Breast Cancer: Assessment With Ultrasound-Guided Fine-Needle Aspiration Cytology and Sentinel Lymph Node Biopsy

Background Axillary assessment is a key component of breast cancer care because nodal involvement affects prognosis, staging, and treatment selection. Ultrasound-guided fine-needle aspiration cytology (US-FNAC) can provide preoperative cytological evidence of axillary metastasis. This study assessed whether positive US-FNAC findings in clinically node-negative (cN0) early breast cancer were associated with a higher axillary nodal burden than sentinel lymph node biopsy (SLNB) positivity. Methods This prospective observational study was performed at Bangladesh Medical University (BMU), Dhaka, Bangladesh, from August 2021 to July 2022. The study included 32 women with histologically confirmed early breast cancer and a cN0 axilla. All patients underwent preoperative axillary ultrasonography (AUS). Patients with detectable axillary lymph nodes (ALNs) underwent US-FNAC; those with positive US-FNAC results proceeded directly to axillary lymph node dissection (ALND), whereas those with negative US-FNAC results or no detectable lymph nodes underwent SLNB, followed by ALND if SLNB was positive. Final axillary histopathology served as the reference standard for evaluating the diagnostic performance of US-FNAC and comparing axillary nodal burden. Results AUS showed no lymph nodes in 16 (50.0%) patients, suspicious nodes in six (18.8%) patients, and non-suspicious nodes in 10 (31.2%) patients. The median metastatic ALN count was higher among US-FNAC-positive patients than among SLNB-positive patients (4.0 vs. 2.5; p = 0.094). More than three metastatic nodes were found in six (85.7%) US-FNAC-positive patients and three (37.5%) SLNB-positive patients. US-FNAC had a sensitivity of 87.5%, specificity of 100.0%, positive predictive value (PPV) of 100.0%, negative predictive value (NPV) of 88.9%, and an overall accuracy of 93.7%. Conclusion In patients with early breast cancer and a cN0 axilla, positive preoperative US-FNAC was associated with heavier axillary metastatic involvement. These findings support the role of US-FNAC in preoperative axillary staging and surgical decision-making.