Preoperative systemic inflammatory indices predict disease-free survival after curative-intent resection for non-small-cell lung cancer

Systemic inflammation plays a crucial role in cancer progression and may influence outcomes after surgical treatment. Blood count–derived inflammatory indices such as the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and systemic immune-inflammation index (SII) have been proposed as prognostic biomarkers in several malignancies. However, their prognostic value in surgically treated non-small-cell lung cancer (NSCLC), particularly for recurrence-related outcomes, remains incompletely defined. We retrospectively analyzed 132 patients with histologically confirmed NSCLC who underwent curative-intent anatomical lung resection between January 2022 and December 2025. Preoperative inflammatory markers (NLR, PLR, SII) were calculated from blood counts obtained within 14 days before surgery. Associations with clinicopathologic features, postoperative complications, and disease-free survival (DFS) were assessed using non-parametric tests, Kaplan–Meier survival analysis, Cox proportional hazards regression, and receiver operating characteristic (ROC) curve analysis. The median age was 64.5 years and 64.4% of patients were male. Adenocarcinoma cases demonstrated higher lymphocyte counts and lower PLR compared with non-adenocarcinoma tumors. Inflammatory indices increased significantly with advancing tumor size–based T category. During follow-up, 20 DFS events were observed. In univariable Cox regression, higher log-transformed NLR (HR 2.34, 95% CI 1.09–5.01; p = 0.029), PLR (HR 2.56, 95% CI 1.12–5.89; p = 0.027), and SII (HR 2.06, 95% CI 1.14–3.74; p = 0.017) were associated with shorter DFS. In the primary multivariable model, logNLR remained associated with recurrence risk (adjusted HR 2.18, 95% CI 1.01–4.72; p = 0.046). In a pre-specified Firth penalized stage-adjusted sensitivity analysis, this association was attenuated and no longer statistically significant (adjusted HR 2.05, 95% CI 0.94–4.44), indicating substantial overlap between NLR and tumour stage. ROC analysis demonstrated moderate predictive performance of NLR for DFS events (AUC 0.67). An exploratory cutoff analysis suggested that NLR values above 2.0 were associated with worse DFS. Preoperative systemic inflammatory indices are associated with tumor burden and disease-free survival in surgically treated NSCLC. Among the evaluated markers, NLR demonstrated the most consistent prognostic signal. These findings support further investigation of inflammation-based biomarkers as adjunct tools for recurrence risk stratification in operable lung cancer. We confirm that our study is not a clinical trial. “Clinical trial number not applicable.”