Axillary Lymph Node Burden in Invasive Breast Cancer: A Comparison of the Predictive Value of Ultrasound-Guided Needle Biopsy and Sentinel Lymph Node Biopsy

BackgroundRecent studies suggest that axillary lymph node dissection (ALND) may be omitted in select breast cancer patients with a positive sentinel lymph node biopsy (SLNB). As we trend away from ALND, we must understand the burden of axillary disease among various patient subgroups. For patients with positive nodes determined using ultrasound-guided needle biopsy (USNB), there are no data regarding the extent of axillary disease.Patients and MethodsAn institutional breast cancer registry was retrospectively reviewed to identify women with invasive cancer and a positive USNB/SLNB who had completion ALND. For statistical analysis, we used χ2 and 1-way analysis of variance.ResultsOne hundred ninety-nine USNB-positive (USNB+) patients and 434 SLNB+ patients were eligible for the study. Positive USNB patients were significantly older, had larger tumors, and were more likely to be estrogen receptor-negative/progesterone receptor-negative and HER2/neu+ than SLNB+ patients. USNB+ patients had much higher rates of N2 (33.2% vs. 12.4%; P < .05) and N3 (17.1% vs. 3.9%; P < .05) disease compared with SLNB+ patients. Higher axillary disease burden was demonstrated in USNB patients who were clinically node negative and those who met Z11 criteria.ConclusionPatients with invasive breast cancer with a positive node on USNB have a significantly greater burden of axillary disease compared with patients with a positive SLNB. USNB+ patients represent a distinct patient population and further research is required to determine if these patients can be safely exempted from axillary dissection.