Abstract PS4-10-14: Prognostic and Predictive Role of Neutrophil-to-Lymphocyte and Platelet-to-Lymphocyte Ratios in Triple-Negative Early Breast Cancer Treated with Neoadjuvant Chemoimmunotherapy

Abstract Background: The integration of immune checkpoint inhibitors into neoadjuvant chemotherapy (NACT) has improved pathological complete response (pCR) rates in early-stage triple-negative breast cancer (eTNBC). However, reliable biomarkers of response are still lacking. Systemic inflammatory indices such as the neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) have emerged as potential prognostic and predictive markers in several solid tumors, included eTNBC. We evaluated the impact of baseline NLR and PLR in pathological response and survival outcomes in patients with eTNBC treated with neoadjuvant chemo-immunotherapy. Methods: A retrospective analysis was performed in patients with eTNBC treated with NACT combined with pembrolizumab. Baseline blood counts (pre-treatment) were used to calculate basal NLR and PLR. pCR was defined as no residual invasive cancer in breast and lymph nodes (RCB-0). Median values and interquartile ranges (IQRs) of NLR and PLR were compared between patients who achieved pCR and those with residual disease. Multivariate logistic regression assessed predictors of pCR. Cox proportional hazards models evaluated associations with invasive disease-free survival (iDFS) and overall survival (OS). Results: Seventy-nine patients were included; median age was 50 years (ED 10.4). The overall pCR rate was 64,2% (N:43). Baseline median NLR was 1.81 (IQR 1.37-2.55); PLR was 133.0 (IQR 104.5-164.9). No statistically significant differences in baseline NLR or PLR were observed between pCR and non-pCR groups (NLR: p=0.596; PLR: p=0.652). In multivariate analysis, baseline NLR >1.8 was not associated with pCR (OR 1.02; 95% CI 0.26-3.93; p=0.98). A non-significant trend toward lower pCR was observed among patients receiving antibiotics prior to treatment (OR 0.69; p=0.48). Regarding survival, pCR was associated with a favorable trend for both iDFS (p=0.19) and OS (p=0.082). Baseline NLR >1.8 showed a non-significant association with worse iDFS (coef. -2.21; p=0.19) and OS (coef. -1.79; p=0.30). Clinical T3-T4 tumors showed a trend toward poorer survival outcomes but did not reach significance. Conclusions: In this cohort of patients with localized TNBC treated with neoadjuvant chemoimmunotherapy, baseline NLR and PLR did not significantly predict pCR or survival outcomes. Although trends suggest that elevated NLR may correlate with poorer prognosis, these findings were not statistically significant, possibly due to limited sample size. Further validation in larger prospective cohorts is warranted. Citation Format: A. Godoy-Ortiz, A. Romanos-Nanclares, P. Vazquez-Rojas, B. Villaescusa-Gonzalez, A. Sanchez-Muñoz, E. Alba-Conejo. Prognostic and Predictive Role of Neutrophil-to-Lymphocyte and Platelet-to-Lymphocyte Ratios in Triple-Negative Early Breast Cancer Treated with Neoadjuvant Chemoimmunotherapy [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 PS4-10-14.