Prognostic Value of Pre-Treatment Neutrophil-To-Lymphocyte Ratio and Platelet-To-Lymphocyte Ratio in Patients With Brain Metastasis From Lung Cancer: A systematic Review and Meta-Analysis.

In modern clinical medicine, lung cancer is one of the most common types of cancer, and the brain is a routine organ of metastasis. Recently, researchers have evaluated hematologic indicators, such as the neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR), and confirmed that they are valid indices for predicting the outcome of patients with lung cancer. However, their prognostic significance for patients with lung cancer who have progressed to brain metastasis (BM) has not been clarified. Our study performed and reported a meta-analysis focusing on the association of pre-treatment NLR, PLR, and overall survival (OS) in lung cancer patients with BM. We searched the PubMed, Embase, and China National Knowledge Infrastructure databases using the PRISMA strategy. Meta-analyses of OS were performed using random-effects models because of the significant heterogeneity. We included 11 articles to evaluate NLR and PLR in 1,977 eligible patients. The NLR group consisted of 11 studies whose meta-analysis showed that OS was significantly shorter in patients with high NLR than in those with low NLR (pooled HR=1.84 (95% CI: 1.47-2.31). Five studies were included in the PLR group, and the results suggested that OS was significantly shorter in patients with high PLR than in those with low PLR (pooled HR=1.53 (95% CI: 1.07-2.20). Our meta-analysis showed a statistically significant association between NLR, PLR, and OS. Lower pre-treatment NLR and PLR predicted a better OS.