Baseline Neutrophil-to-Lymphocyte Ratio Predicts Overall Survival in PD-L1-positive Advanced Triple-negative Breast...

Immune checkpoint inhibitors (ICIs) have improved clinical outcomes in patients with advanced triple-negative breast cancer (TNBC); however, substantial heterogeneity exists in treatment durability and survival. Simple blood-based immune markers may provide prognostic information; however, their clinical relevance in ICI-treated TNBC remain unclear.

We conducted a retrospective single-center study of patients with advanced TNBC treated with ICIs, including atezolizumab or pembrolizumab. Baseline peripheral immune markers - absolute lymphocyte count (ALC) and neutrophil-to-lymphocyte ratio (NLR) - were evaluated prior to treatment initiation. Time-to-treatment failure (TTF) and overall survival (OS) were analyzed using the Kaplan-Meier method and Cox proportional hazards model.

A total of 43 patients were included. In the Kaplan-Meier analysis, high baseline NLR was significantly associated with both shorter TTF and OS. Low baseline ALC was significantly associated with shorter TTF but not with OS. In the multivariate Cox proportional hazards analysis of TTF, no baseline clinical or immune parameters were identified as independent prognostic factors. In contrast, multivariate analysis for OS demonstrated that high baseline NLR was the only independent prognostic factor.

NLR was independently associated with OS, suggesting it functions as a prognostic marker of systemic inflammatory and immune balance. In contrast, ALC was associated with treatment durability but not long-term survival, indicating its relevance to treatment tolerance rather than survival outcomes. These findings highlight the clinical utility of simple blood-based immune markers for risk stratification in ICI-treated TNBC.