Association between preoperative inflammatory biomarkers and postoperative pulmonary complications in stage I-II non-small cell lung cancer: a retrospective study.

Background: Postoperative pulmonary complications (PPCs) significantly impact outcomes in early-stage non-small cell lung cancer (NSCLC). The relationship between preoperative inflammatory biomarkers and PPCs in stage I-II NSCLC was assessed in this study. Methods: This retrospective analysis included 548 patients with stage I-II NSCLC who underwent surgery between 2016 and 2025. To control for confounding, 1:3 propensity score matching (PSM) was performed using clinical and surgical factors. Preoperative levels of the systemic immune-inflammation index (SII), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and lymphocyte-to-monocyte ratio (LMR) were calculated. The associations with postoperative pulmonary complications (PPCs) were assessed using logistic regression. Discriminatory performance was evaluated using the area under the receiver operating characteristic curve (AUC), and comparisons were made with the DeLong test. Results: After PSM, 294 patients (75 with PPCs, 219 without) were analyzed, with well-balanced baseline characteristics. In multivariate analysis adjusted for BMI and surgical duration, elevated SII (adjusted OR for the highest quartile [Q4]: 5.53, 95% CI: 4.31-7.18, Conclusion: Preoperative SII and NLR are independent predictors for PPCs in stage I-II NSCLC, with SII showing the best single-biomarker performance, albeit with a low AUC. Further research should explore combining SII with additional biomarkers to enhance predictive value.