A validation study on the lung immune prognostic index for prognostic value in patients with locally advanced non–small cell lung cancer

•The baseline LIPI is a convenient and promising prognostic maker for patients with inoperable LA-NSCLC.•The baseline LIPI was correlated with overall survival, progression-free survival, and locoregional relapse-free survival in patients with inoperable LA-NSCLC.•The baseline LIPI might be used to guide clinical treatment decisions. Baseline lung immune prognostic index (LIPI) was reported as a potential predictive biomarker of immune checkpoint inhibitor treatment and a prognostic biomarker for metastatic non-small cell lung cancer (NSCLC). However, it remains unclear whether LIPI is associated with outcomes in locally advanced NSCLC (LA-NSCLC). Patients with LA-NSCLC receiving radiotherapy between 2000 to 2017 were retrospectively reviewed. Based on pretreatment dNLR and LDH level made up LIPI per previous publications, patients were divided into good group (0 score) and intermediate-poor group (1 or 2 scores). Propensity score matching (PSM) was conducted to balance confounding variables. A total of 1079 patients were eligible for analysis. Patients with intermediate-poor pretreatment LIPI had inferior overall survival (OS), progression-free survival (PFS), locoregional relapse-free survival (LRRFS), and distant metastasis-free survival (DMFS) than those with good LIPI. Multivariate analysis suggested that LIPI was an independent prognostic marker for OS (hazard ratio [HR] = 1.19, 95% CI: 1.02–1.40), PFS (HR = 1.18, 95% CI: 1.02–1.36), and LRRFS (HR = 1.22, 95% CI: 1.05–1.41) in patients with inoperable LA-NSCLC. PSM analysis further verified that intermediate-poor LIPI was an independent prognostic factor for shorter survivals (OS, PFS and LRRFS). LIPI is a simple and promising prognostic marker for patients with unresectable LA-NSCLC. Further prospected studies are warranted to validated these findings.