Systemic Inflammation Biomarkers Predict Survival in Patients of Early Stage Non-Small Cell Lung Cancer Treated With Stereotactic Ablative Radiotherapy - A Single Center Experience

Background: Increasing evidence indicates a relationship between systemic inflammation and survival following treatment in various tumors. However, the correlation of systematic inflammation with survival after stereotactic ablative radiotherapy (SABR) in early stage non-small cell lung cancer (NSCLC) has not been well established. Patients and methods: We retrospectively analyzed patients with newly diagnosed early stage NSCLC treated with SABR in a single institution from 2011 to 2015. The neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), and lymphocyte- monocyte ratio (LMR) were calculated as systemic inflammation biomarkers. Overall survival (OS) was the first end-point. Receiver operating characteristic (ROC) was used to determine cut-off points for OS. Univariate and multivariate Cox proportional hazards regression were used to investigate the potential factors associated with OS. Results: In the 63 patients who were eligible for analysis. The median follow up after SBRT was 29.5 months (range 8-67 months) while the 3-year OS was 74.2%. Based on ROC analysis, optimal cut-off values of NLR, PLR, and LMR were 2.06, 199.55 and 4.0, respectively. Significant survival benefit was found in the NLR ≤2.06 group (p=0.028), PLR≤199.55 group (p=0.001), and LMR˃4.0 group (p=0.046). Univariate analysis indicated that low NLR (p=0.011), low PLR (p=0.003), and high LMR (p=0.014) were correlated with improved survival. Multivariate analysis indicated that high PLR (p=0.033) and low LMR (p=0.046) were independent prognostic factors for poor survival. Conclusions: In patients of early stage NSCLC who received SABR, pretreatment NLR, PLR, and LMR could be considered useful prognostic indicators of OS. These metrics may provide reliable and convenient predictors to identify patients who would benefit from SABR.