Abstract PS1-26: Sentinel lymph node biopsy alone in locally advanced breast cancer after neoadjuvant chemotherapy: Turkish multicentric neosenti-turk MF-18-02-study

BACKGROUND: Omitting axillary lymph node dissection (ALND) following sentinel lymph node biopsy (SLNB) in patients with locally advanced breast cancer (LABC) after neoadjuvant chemotherapy (NAC) is still controversial. In this study, we evaluated factors affecting local recurrence and outcome in patients with LABC, who underwent SLNB alone after NAC. METHODS: Between 2004 to 2018, 320 patients with clinically node-positive LABC who received NAC and underwent SLNB alone after negative axillary staging were analyzed. All patients had breast and/or regional nodal irradiation. RESULTS: Median age was 46 (23-70). Of those, 228 patients had ypN0 disease (71.25%), whereas 92 patients had ypN(+) disease including 19 (20.6%) isolated tumor cells (ITC), 33 micrometastasis (35.9%) and 40 macrometastases (43.5%). At a median follow-up of 37 months (24-172), one patient (0.3%) with macrometastatic SLN having extracapsular extension was found to have locoregional recurrence at the 60th month. Five-year disease-free survival (DFS) and disease specific survival (DSS) rates were found as 87% and 95%, respectively. Patients with cT3&4 (HR=2.22, 95% CI; 1.07-4.62), non-luminal molecular pathology (HR=2.71, 95% CI, 1.23-5.97), and non-pCR in the breast (HR=2.21, 95% CI, 0.94-5.17) were found to have an increased HR compared to others in 5-year DFS. However, no significant differences could be found between patients ypN0, ypN-ITCm 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS1-26.