Usefulness of White Blood Cell Differential-based Indices in Patients With Extensive-stage Small Cell Lung Cancer

Background/Aim: Indices based on the white blood cell (WBC) count and WBC differential count are simple and can be easily calculated using routine blood tests. Many studies have examined the usefulness of these indices for predicting prognosis for various cancers, including lung cancer. However, no studies have focused on the relationships between indices based solely on WBC and WBC differential counts and the prognosis of patients with extensive-stage small cell lung cancer (ES-SCLC). The aim of this study was to evaluate the prognostic value of indices based on WBC and WBC differential counts in patients with ES-SCLC treated with platinum-doublet chemotherapy. Patients and Methods: The pretreatment neutrophil-to-lymphocyte ratio (NLR), derived neutrophil-to-lymphocyte ratio (dNLR), neutrophil-to-monocyte ratio (NMR), monocyte-to-lymphocyte ratio (MLR), neutrophil-to-WBC ratio (NWR), lymphocyte-to-WBC ratio (LWR), monocyte-to-WBC ratio (MWR), neutrophil-to-eosinophil ratio (NER), lymphocyte-to-eosinophil ratio (LER), monocyte-to-eosinophil ratio (MER), eosinophil*neutrophil-to-lymphocyte ratio (ENLR), systemic inflammation response index (SIRI), and inflammatory related ratio (IRR) of patients with ES-SCLC who were treated with platinum-doublet chemotherapy as first-line treatment at Kainan Hospital were retrospectively analyzed. Results: Data from 102 patients were analyzed. On multivariate analysis, patients with low MLR, MWR, NER, MER, and IRR values had significantly longer overall survival (OS) than patients with high MLR, MWR, NER, MER, and IRR values. In addition, patients with low WBC and monocyte counts had significantly longer OS than patients with high WBC and monocyte counts. Conclusion: Indices based on WBC and WBC differential counts, especially monocyte-related indices, may be useful markers for predicting the prognosis of patients with ES-SCLC treated with platinum-doublet chemotherapy.