Prognostic value of the platelet-to-lymphocyte ratio in lung cancer patients receiving immunotherapy: A systematic review and meta-analysis

BACKGROUND: Current studies have revealed that the platelet to lymphocyte ratio (PLR) may lead to a poor prognosis in lung cancer patients receiving immunotherapy. We conducted a meta-analysis to explore the prognostic value of PLR in lung cancer patients receiving immunotherapy. METHODS: We retrieved potential studies from the PubMed, Web of Science, Embase, and Scopus databases up to June 2021 and merged the hazard ratios (HRs) and the corresponding 95% confidence intervals (CIs) to evaluate the association between PLR and overall survival (OS) or progression-free survival. RESULTS: Fourteen studies involving 1761 patients were included in our meta-analysis. The results indicated that an elevated level of pretreatment PLR was associated with poorer OS and PFS in lung cancer patients receiving immunotherapy (OS: HR = 1.88, 95% CI: 1.37–2.58; PFS: HR = HR = 1.40, 95% CI: 1.11–1.76). The association remained consistent after subgroup analysis and was robust even after sensitivity analysis. CONCLUSIONS: PLR may be a prognostic factor of lung cancer patients receiving immunotherapy, which can lead to worse survival outcomes. However, further studies are necessary for evidence in clinical application.