Abstract PS4-01-02: A Comparative Analysis of TAR and NLR in Patients with triple negative breast cancer treated with as KEYNOTE-522 trial : Distinct Predictors of Pathologic Response and Survival

Abstract Background) Pathologic complete response (pCR) has been widely used as a surrogate marker for relevant outcomes in breast cancer patients undergoing neoadjuvant treatment. However, the prognostic value of pCR varies by subtype, with triple-negative breast cancer (TNBC) showing one of the strongest associations. Notably, some patients achieving pCR still experience recurrence, suggesting that pCR and survival outcomes such as event-free survival (EFS) may represent distinct biological endpoints from different processes. This study investigated whether the tumor-aorta ratio based on Hounsfield units (TAR) and the neutrophil-to-lymphocyte ratio (NLR) function as distinct predictive biomarkers for pCR and EFS in TNBC patients treated with the KEYNOTE-522 regimen. Materials and Methods) Patients with TNBC who received neoadjuvant systemic therapy according to the KEYNOTE-522 regimen were included. Clinicopathologic data, including TAR and NLR values, were collected and analyzed. Group comparisons were performed using independent t-tests or Mann-Whitney U tests, as appropriate. Statistical analyses were conducted using SPSS version 29, with a p-value <0.05 considered statistically significant. Results) Initial TAR was significantly associated with pCR (p = 0.022), supporting its role as a predictive biomarker for immediate tumor response. In contrast, EFS was more strongly associated with post-treatment NLR, a systemic immune marker (p < 0.001). TAR decreased consistently after treatment, regardless of pCR status or the occurrence of subsequent events, suggesting that TAR may reflect structural tumor regression. In contrast, NLR exhibited divergent post-treatment patterns. Among patients without events, NLR increased from 1.99 ± 0.85 to 2.50 ± 2.88. However, in patients who experienced events, NLR decreased from 2.26 ± 1.05 to 1.21 ± 0.45. Further analysis revealed that neutrophil counts changed in opposite directions depending on event occurrence, while lymphocyte counts decreased across both groups. Conclusion) This study suggests that pCR and EFS may require distinct predictive biomarkers, with TAR and NLR reflecting different biological processes: localized tumor response versus systemic immune activity. Importantly, in this uniform cohort of TNBC patients treated with an identical neoadjuvant regimen, an increase in NLR—driven primarily by increased neutrophil counts—was associated with better prognosis. These findings raise the possibility that neutrophil-mediated immune responses may contribute to improved clinical outcomes, underscoring the potential relevance of systemic immune dynamics in the context of outcome. Citation Format: A. Han, H. Choi, J. Ahn, H. Ahn, J. Shin, J. Song, Y. Park. A Comparative Analysis of TAR and NLR in Patients with triple negative breast cancer treated with as KEYNOTE-522 trial : Distinct Predictors of Pathologic Response and Survival [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2025; 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(4 Suppl):Abstract nr PS4-01-02.