Complete Blood Count-Based Biomarkers as Predictors of Clinical Outcomes in Advanced Non-Small Cell Lung Cancer Patients with PD-L1 < 50% Treated with First-Line Chemoimmunotherapy

<b>Background:</b> The aim of the study was to investigate a series of complete blood cell count-based biomarkers of systemic inflammation as predictors of clinical outcomes in patients who underwent first-line chemoimmunotherapy for advanced NSCLC. <b>Methods:</b> Consecutive patients with pathologically diagnosed stage III/IV NSCLC and PD-L1 < 50% who underwent first-line chemoimmunotherapy were retrospectively enrolled. The clinical outcomes used for biomarker evaluation were Objective Response Rate (ORR) and Overall Survival (OS). <b>Results:</b> Non-responders had significantly higher values of neutrophil to lymphocyte ratio (NLR, median: 5.36; IQR: 2.78-10.82 vs. 3.31; IQR: 2.15-4.12, <i>p</i> = 0.019), neutrophil to monocyte ratio (NMR, median: 14.00; IQR: 8.82-21.20 vs. 9.20; IQR: 7.45-11.20, <i>p</i> = 0.013), and systemic inflammation index (SII, median: 1395; IQR: 929-3334 vs. 945; IQR: 552-1373, <i>p</i> = 0.025), but only NLR and NMR remained independently associated with clinical response in multivariate logistic regression. In the univariate analysis, white blood cells (OR:1.2202; 95% CI: 1.0339-1.4400, <i>p</i> = 0.019), neutrophils (OR:1.2916; 95% CI: 1.0692-1.5604, <i>p</i> = 0.008), NLR (OR:1.3601: 95% CI: 1.0949-1.6896, <i>p</i> = 0.005) and NMR (OR:1.2159; 95% CI: 1.00396-1.4221, <i>p</i> = 0.015) were significantly associated with survival; Cox regression models confirmed that neutrophils, NLR, and MLR were independently associated with survival; NLR, at a cut-off value of 4.0, showed the better AUC (0.749) in predicting OS. <b>Conclusions:</b> Baseline complete blood cell count biomarkers, especially the NLR, can predict clinical outcomes in patients with advanced NSCLC treated with first-line chemoimmunotherapy.