Higher aorta dose increased neutrophil‐to‐lymphocyte ratio resulting in poorer outcomes in stage II‐III non‐small cell lung cancer

BACKGROUND: This study focused on the relationship between the neutrophil‐to‐lymphocyte ratio (NLR) and the dose of organs at risk in patients with stage II–III non‐small cell lung cancer (NSCLC) receiving intensity‐modulated radiotherapy. METHODS: The clinical characteristics and dosimetric parameters of 372 patients were collected retrospectively. A high NLR was defined as that ≥1.525. Survival analysis was conducted using the Kaplan–Meier and Cox regression analysis. Least absolute shrinkage and selection operator (LASSO) analysis was conducted to select appropriate dosimetric parameters. The risk factors of NLR were evaluated using univariate and multivariate logistic regression analyses. RESULTS: Patients with a high NLR had poorer progression‐free survival (PFS) (p = 0.011) and overall survival (OS) (p = 0.061). A low NLR (<1.525) predicted better PFS (hazard ratio [HR] 0.676, 95% confidence interval [CI]: 0.508–0.900, p = 0.007) and OS (HR 0.664, 95% CI: 0.490–0.901, p = 0.009). The aorta dose differed between the low and high NLR groups (all <0.1) in the univariate analysis. An aorta V10 was confirmed as a significant risk factor for a high NLR (odds ratio [OR] 1.029, 95% CI: 1.011–1.048, p = 0.002). Receiving chemotherapy before (OR 0.428, 95% CI: 0.225–0.813, p = 0.010) and during (OR 0.491, 95% CI: 0.296–0.815, p = 0.006) radiotherapy were predictive factors of a low NLR. CONCLUSION: The aorta dose was significantly associated with a high NLR. Patients with stage II–III NSCLC with a high NLR had poorer prognosis. Receiving chemotherapy before and/or during radiotherapy predicted a low NLR.