Abstract P2-01-08: Does axillary lymph node ratio still have a prognostic value in neoadjuvant setting?

Abstract Background : Axillary nodal status is one of the most important prognostic factor in breast cancer. The lymph node ratio has been reported as an independent prognostic factor because the dissected and involved lymph node could be different across the institutions along with surgical and pathologic procedure. Neoadjuvant chemotherapy has been preferred treatment method in locally advanced breast cancer for the purpose of reducing tumor mass in breast and/or axillary area. Neoadjuvant chemotherapy would downstage axillary nodal status and lower total number of excised lymph nodes compared with upfront surgery. Therefore, there has been emerged question whether the axillary nodal status and lymph node ratio following neoadjuvant chemotherapy could accurately predict the prognosis. To answer this question, we evaluated the axillary nodal status and lymph node ratio as a prognostic factor after neoadjuvant chemotherapy. Methods : One hundred thirty two patients were eligible in this study between 2005 and 2011. The patients underwent breast surgery after 3 or 6 cycles of anthracycline with or without taxane based chemotherapy according to their axillary nodal status. The cut-off range of lymph node ratio were divided to low (≤0.20, n=45), intermediate (2<, ≤0.65, n=25) and high (<0.65, n=6). Clinical and pathologic factors including hormone status, tumor size, lymphovascular invasion and response to chemotherapy were evaluated and survival results were also investigated with nodal status. Results : Mean age of total patients was 48 years. Mean follow up period was 40 months. The pathologic complete responses were observed 33% in breast, 25% in axillar, 17.4% in both areas, respectively. Tumor subtype was an independent factor for pathologic response rate. With multivariate analysis, clinical tumor size, pathologic nodal status and the presence of lymphovascular invasion were statistically significant to disease free survival in overall cohort. In node negative patients group (n=57), the hormone receptor status and molecular subtype were associated with the disease free survival using multivariate analysis. Whereas, pathologic tumor size, pathologic nodal status and lymph node ratio, especially lower cut-off limit 0.20, were significant risk factor for disease free survival in node positive (n=75) patients. Conclusion : Neoadjuvant chemotherapy significantly affect axillary nodal status. Traditional nodal staging has been accepted as important prognostic factor. The response to neoadjuvant chemotherapy depends on tumor subtype. In this study, we proved that nodal ratio could be a candidate as prognostic factor in neoadjuvant setting and 0.20 is acceptable lower cut-off value of lymph node ratio. Citation Format: Seung Pil Jung, Hye Yoon Lee, Woo Young Kim, Hee Yong Kwak, Jae Bok Lee, Hoon Yub Kim, Jeoung Won Bae. Does axillary lymph node ratio still have a prognostic value in neoadjuvant setting? [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P2-01-08.