LAUSR

Purpose Although serum neutrophil-to-lymphocyte ratio (NLR) is correlated with the outcome of various cancer types, its role in treatment-naïve, advanced, epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer (NSCLC) patients treated with osimertinib remains uncertain. We have the intention to use this biomarker to evaluate the outcomes in NSCLC. Patients and Methods Advanced EGFR-mutant NSCLC patients receiving osimertinib as the first-line treatment were included. We evaluated the prognostic role of baseline NLR and explored its association with patients’ characteristics. A high NLR was defined as pretreatment serum NLR ≥ 5. Results A total of 112 eligible patients were included. The objective response rate was 83.7%. The median progression-free survival (PFS) and overall survival (OS) were 20.5 months (95% CI 14.5–26.5) and 47.3 months (95% CI 36.7–58.2), respectively. A high NLR predicted an inferior PFS (HR 1.90 [95% CI 1.02–3.51], P = 0.042) and OS (HR 3.85 [95% CI 1.39–10.66], P = 0.009). Patients with stage IVB disease were more likely to have a high baseline NLR than those with stage IIIB-IVA (33.9% vs 15.1%, P = 0.029). Other patients’ characteristics did not correlate with the baseline NLR significantly. Patients with a high NLR had significantly more metastatic organs than those with a low NLR (2.5 ± 1.3 vs 1.8 ± 0.9, P = 0.012), particularly brain, liver, and bone metastasis. There was no significant association between NLR and intrathoracic metastasis. Conclusion Baseline serum NLR could act as an important prognostic marker for EGFR-mutant NSCLC patients receiving first-line osimertinib. A high NLR was associated with higher metastatic burden, more extrathoracic metastases, and therefore, a worse outcome.