Prognostic significance of pretreatment neutrophil-to-lymphocyte ratio in triple-negative breast cancer: A systematic review and meta-analysis.

Abstract

e13121 Background: Triple-negative breast cancer (TNBC) lacks reliable prognostic biomarkers beyond standard clinical staging, limiting individualized risk stratification and treatment planning. The neutrophil-to-lymphocyte ratio (NLR), a readily available marker of systemic inflammation, has been proposed as a prognostic indicator in TNBC; however, existing evidence remains inconsistent. We performed an updated systematic review and meta-analysis to evaluate the prognostic value of pretreatment NLR in the contemporary treatment era. Methods: PubMed, Embase, Cochrane CENTRAL, and ClinicalTrials.gov were systematically searched from database inception through January 1, 2026, for randomized and observational studies reporting associations between pretreatment NLR and survival outcomes in TNBC. Two reviewers independently screened studies and extracted data with discrepancies resolved by consensus. Outcomes included overall survival (OS), disease-free survival (DFS), and progression-free survival (PFS). Hazard ratios (HRs) were pooled using random-effects models. Risk of bias was assessed using ROBINS-I tool. Prespecified subgroup and sensitivity analyses were performed based on NLR cut-off values, follow-up duration, geographic region, and risk of bias. Results: Twenty-three retrospective studies comprising 4,731 patients with TNBC were included. On multivariate analysis, elevated pretreatment NLR was independently associated with poorer OS (HR 2.21, 95% CI: 1.56–3.13) and DFS (HR 1.97, 95% CI: 1.65–2.37. Similar associations were observed on univariate analysis (OS: HR 1.70, 95% CI: 1.07–2.72; DFS: HR 1.84, 95% CI: 1.14–2.98). No statistically significant or consistent association was observed between NLR and PFS. Associations between high NLR and adverse OS and DFS remained robust across prespecified subgroup and sensitivity analyses, representing the largest contemporary synthesis of multivariable-adjusted outcomes in TNBC. Key pooled outcome associations are summarized in Table 1. Conclusions: Elevated pretreatment NLR is independently associated with worse OS and DFS in patients with TNBC, supporting its potential role as a low-cost tool for clinical risk stratification and treatment planning. Given its availability from routine blood tests, NLR may assist in identifying high-risk patients who could benefit from intensified surveillance or therapeutic strategies. Prospective validation in the modern chemo-immunotherapy era is warranted. Summary of pooled associations between pretreatment NLR and survival outcomes in TNBC. Outcome Studies (n) Interpretation Overall survival 14 Worse survival Disease-free survival 15 Worse survival Progression-free survival 3 Inconclusive