Prognostic value of platelet to lymphocyte ratio in non-small cell lung cancer: evidence from 3,430 patients

This study was designed to explore the association between elevated platelet to lymphocyte ratio (PLR) and prognosis of patients with non-small cell lung cancer (NSCLC) by meta-analysis. A total of 11 studies with 3,430 subjects were included and the combined hazard ratio (HR) and 95% confidence intervals (95% CI) were calculated. The data showed that elevated PLR predicted poor overall survival (OS) (HR = 1.42; 95% CI: 1.25–1.61, p < 0.001; I(2) = 63.6, P(h) = 0.002) and poor disease-free survival (DFS)/progression-free survival (PFS) (HR = 1.19; 95% CI: 1.02–1.4, p = 0.027; I(2) = 46.8, P(h) = 0.111). Subgroup analysis showed elevated PLR did not predict poor OS in patients included in large sample studies (HR = 1.44; 95% CI: 0.94–2.21, p = 0.098) whereas petients with Caucasian ethnicity (HR = 1.59; 95% CI: 1.27–1.98, p < 0.001) and PLR cut-off value >180 (HR = 1.61; 95% CI: 1.3–1.99, p < 0.001) had enhanced prognostic efficiency for OS. Subgroup analysis also demonstrated that high PLR did not predict poor DFS/PFS in Asian patients. In conclusion, our meta-analysis suggested that elevated PLR was associated with poor OS and DFS/PFS in NSCLC. In addition, high PLR especially predicted poor OS in Caucasians but had no association with poor DFS/PFS in Asians.