Use of neutrophil/lymphocyte ratio (NLR) and lymphocyte/monocyte ratio (LMR) as biomarkers in the differential diagnosis of malignant solitary pulmonary nodules

Abstract

Objective: Histopathological diagnosis of atypical lung nodules is often not possible in the preoperative period. This study evaluates the diagnostic value of neutrophil/lymphocyte ratio (NLR) and lymphocyte/monocyte ratio (LMR) as biomarkers in the differentiation of undiagnosed lung nodules. Material and Methods: The study includes 91 patients (21 females, 70 males, mean age: 59.35 ± 11.85, age interval 20-81) operated on for lung nodules between September 2010 and September 2020. Age, gender, type of operation performed, histopathological type of the tumor, nodule size, SUVmax values measured on PET-CT, preoperative neutrophil/lymphocyte, and lymphocyte/monocyte ratios were analyzed retrospectively. These values were compared in patients with primary lung cancer (Group 1) and patients with secondary lung cancer, that is, patients with lung metastases from other organs (Group 2). Results: NLR was statistically significantly higher in group 2 patients (N: 37)(3.38 ± 2.03). There was no statistically significant difference between the two groups in terms of LMR. Conclusion: For lung nodules with unknown histopathological diagnosis, NLR values lower than 1.69 in preoperative complete blood count suggest primary lung cancer, and values above 2.92 suggest metastasis from other organs to the lung.