Clinical Significance of the Peripheral Blood Neutrophil-to-Lymphocyte Ratio in Predicting Chemotherapy Outcomes for Small Cell Lung Cancer

Objective: This study aims to assess the clinical significance of the peripheral blood neutrophil-to-lymphocyte ratio (NLR) in predicting chemotherapy outcomes for patients with small cell lung cancer (SCLC). Methods: A cohort of 44 patients diagnosed with SCLC between January 2021 to June 2022 at Fuyang People's Hospital was selected for analysis. All patients in this group received a first-line platinum-based doublet chemotherapy regimen. In parallel, a control group consisting of 44 healthy individuals undergoing routine physical examinations at the same hospital was also selected. Fasting venous blood samples were collected in the morning within one week before the initiation of chemotherapy, and a complete blood cell count was performed to calculate the NLR. Results: The NLR in the plasma of patients with SCLC was significantly elevated compared to that of healthy individuals (P < 0.01). After two cycles of chemotherapy, there were no statistically significant differences in plasma NLR in SCLC patients compared to pre- chemotherapy levels (P > 0.05). However, in the subgroup of patients with a partial response (PR) to treatment, the NLR decreased to 2.625 (95% CI: 1.900, 3.625), down from a pre-chemotherapy level of 3.430 (2.688, 4.800) (Z = -3.127, P = 0.002). Conversely, in patients whose disease progressed (PD) following chemotherapy, the NLR increased to 3.880 (95% CI: 2.953, 5.223) from a pre- chemotherapy level of 2.060 (1.915, 2.968) (Z = -2.521, P = 0.012). Conclusion: The dynamic variations in the peripheral blood NLR before and after chemotherapy in patients with SCLC are strongly associated with the efficacy of first-line chemotherapy regimens. These changes in NLR levels may serve as a crucial indicator for predicting the effectiveness of first-line chemotherapy in patients with SCLC.