Pretreatment prognostic nutritional index is associated with survival outcomes in locally advanced NSCLC treated with definitive chemoradiotherapy

Definitive chemoradiotherapy (CRT) remains a curative-intent treatment for unresectable or medically inoperable locally advanced non-small cell lung cancer (NSCLC), although outcomes vary substantially. This retrospective cohort study evaluated the association of pretreatment immune-nutritional biomarkers with survival in 102 patients with histologically confirmed NSCLC treated with definitive-intent CRT. Pretreatment neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and prognostic nutritional index (PNI), defined as 10 × serum albumin (g/dL) + 0.005 × total lymphocyte count (/mm³), were calculated from routine laboratory values. Median follow-up was 56.4 months. Median progression-free survival (PFS) and overall survival (OS) were 15.8 and 29.2 months, respectively. Using the OS-derived PNI cut-off of 43.5, low PNI was associated with shorter PFS (13.3 vs. 19.4 months; HR, 1.99; 95% CI, 1.25–3.19; P = 0.003) and OS (26.4 vs. 31.3 months; HR, 1.70; 95% CI, 1.04–2.79; P = 0.033). In multivariable models, PNI ≤ 43.5 remained independently associated with worse PFS and OS, whereas NLR and PLR were not associated with survival. Pretreatment PNI may support risk stratification before definitive CRT, but external validation is required.