[Meta-analysis of Platelet Lymphocyte Ratio as A Prognostic Factor for
Non-small Cell Lung Cancer]

Current research shows that platelet to lymphocyte ratio (PLR) has important prognostic value in renal cell carcinoma, esophageal cancer, gastric cancer, liver cancer and colon cancer. The aim of the study is to evaluate the prognostic value of PLR in non-small cell lung cancer (NSCLC) through meta-analysis.

Literature search for PubMed, EMBASE, Web of Science, Medline, Cochrane Library, China National Knowledge Internet (CNKI), China Biomedical Medicine disc (CBMdisc), VIP, Wanfang Database using computer electronic system to study the association between PLR and overall survival (OS) and disease-free survival (DFS). Each eligible study data is extracted and a meta-analysis is performed using the hazard risk (HR) and 95% confidence interval (95%CI) to assess the prognostic value of PLR, the time limit for the search is to build the library until November 2018.

We include a total of 15 research literatures involving 5,524 patients for meta-analysis. According to the results of the meta-analysis: The OS of the higher PLR group is significantly lower than that of the lower PLR group (HR=1.69, 95%CI: 1.45-1.97, P<0.000,01, I²=46.2%, Pheterogeneity=0.026); the DFS of the higher PLR group is significantly lower than that of the lower PLR group (HR=1.41, 95%CI: 1.14-1.74, P=0.001, I²=46.2%, Pheterogeneity=0.026). Subgroup analysis show that the OS of the higher PLR group is still significantly lower than the lower PLR group (P<0.05) after grouping by ethnicity, sample size, PLR cutoff value and treatment.

Increased PLR is associated with poor prognosis in NSCLC, so PLR may be an important biological predictive marker for NSCLC patients, however, its clinical application still needs to be verified through more research in the future.