Abstract P1-01-07: Factors predicting a lower likelihood of residual nodal disease in clinically-node positive patients undergoing sentinel node surgery after neoadjuvant chemotherapy for breast cancer

Background: Residual nodal disease at the completion axillary lymph node dissection (ALND) has been reported in over 60% in patients with a positive sentinel lymph node biopsy (SLNB) after neoadjuvant chemotherapy (NAC). This study aimed to explore whether any clinical or histopathological characteristics of patients may be associated with a lower likelihood of having non-SLN metastasis at ALND. Methods: Between January 2004 to January 2021, 459 patients with cT1-4/N1-3 underwent ALND due to a positive SLNB after NAC. Demographic, clinical and histopathological characteristics of patients were analyzed to predict the non-SLN metastasis at ALND. Sentinel lymph node ratio was defined as the ratio of the number of positive SLN to the total excised SLNs. Results: Median age was 47 (21-84). Of those, the majority of the patients had cT1-2 (67.8%) and cN1 disease (78.1%), whereas 76.5% of tumors were invasive ductal carcinoma. The frequency of non-SLN metastases according to the tumor subtypes were 59.5% in luminal A, 73.8% in HER2(-) luminal B, 60.3% in HER2(+) luminal B, 66.7% in non-luminal HER2(+), and 66.7% in triple negative breast carcinoma. Of those with removal more than 2 SLNs, having 1 positive SLN, or breast pathologic complete response, or cT1-2 disease , or a SLN ratio FactorsOR(95%CI)p-valuecT0.009*1&20.45(0.25-0.82)3&4Reference (1)SLN Status0.006*ITC and micrometastasis0.24(0.09-0.65)MacrometastasisReference (1)SLN-Ratio (%) Citation Format: Neslihan Cabioglu, Hasan Karanlık, Abdullah Igci, Mahmut Muslumanoglu, Mustafa Tukenmez, Selman Emiroglu, Enver Ozkurt, Semen Onder, Pinar Saip, Yesim Eralp, Adnan Aydiner, Ekrem Yavuz, Vahit Ozmen. Factors predicting a lower likelihood of residual nodal disease in clinically-node positive patients undergoing sentinel node surgery after neoadjuvant chemotherapy for breast cancer [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-01-07.