A Positive Node on Ultrasound-Guided Fine Needle Aspiration Predicts Higher Nodal Burden Than a Positive Sentinel Lymph Node Biopsy in Breast Carcinoma

Introduction Axillary status remains an important prognostic indicator in breast cancer. Certain patients with a positive sentinel node (SLNB) may not benefit from axillary clearance (AC). Uncertainty remains if this approach could be applied to patients diagnosed with axillary metastases on ultrasound-guided fine needle aspiration cytology (USFNAC). The aim of this study was to compare nodal burden in patients with positive USFNAC and a positive SLNB. Methods A retrospective study was performed involving all BC patients between 2007 and 2014 who had either pre-operative USFNAC or a SLNB. Patient/tumour characteristics and nodal burden were examined in all patients proceeding to AC. Results 974 patients were eligible for analysis. 439 patients (45 %) had positive USFNAC and 535 (55 %) had a positive SLNB. USFNAC-positive patients were more likely to undergo mastectomy (Chi-square test; p < 0.001), have extra-nodal extension (p < 0.001), be oestrogen receptor negative (p < 0.001) and be HER2 positive (p\ 0.001). The median total number of lymph nodes (LNs) excised during AC was higher in the USFNAC group (Mann-Whitney test; 23 vs. 21; p\ 0.001). The median total number of involved LNs was 3 (range 1-47) in FNAC-positive patients versus 1 (range 1-37) in SLNB-positive patients (p < 0.001). The median number of involved LNs in level 1 was 3 in FNAC-positive patients versus 1 in SLNB-positive patients (p\ 0.001). Within the SLN-positive group, 49 % of the patients had only one involved LN, 28 % had two nodes involved and 23 % had >= 3. In comparison, within the FNAC-positive group only 13 % of the patients had one involved LN, 12 % had two nodes involved and 74 % had >= 3. Conclusion Patients with positive USFNAC have more aggressive clinico-pathological characteristics and higher nodal burden compared to SLNB-positive patients. Currently, the authors advocate that patients not receiving neoadjuvant chemotherapy, with a positive USFNAC, should proceed directly to an axillary ALND.