Background Systemic inflammatory parameters, such as the elevator PLR (platelet-lymphocyte ratio), have been found to be associated with the prognosis in gastric cancer (GC); however, the results remain controversial. So we aimed to evaluate the prognostic role of the PLR in gastric cancer by conducting this meta-analysis. Methods We performed a systematic literature search in PubMed, Embase and the Cochrane Library. The hazard ratio (HR) /Odds Ratio (OR) and its 95% confidence (CI) of survival outcomes and clinicopathological parameters were calculated. Results A total of 49 studies (51 cohorts) with 28,929 GC patients were included in the final meta-analysis. The pooled results showed that elevated PLR was significantly associated with poor overall survival (OS) (HR: 1.37, 95% CI: 1.26–1.49, p < 0.001; I2 = 79.90%, Ph < 0.001) and disease-free survival (DFS) (HR 1.52, 95%CI 1.22–1.90, P < 0.001, I2 = 88.6%, Ph< 0.001) of GC patients. Furthermore, patients with elevated PLR had a higher risk of lymph node metastasis (OR = 1.17, 95% CI: 1.02–1.33, p = 0.023), serosal invasion (T3 + T4) (OR = 1.34, 95% CI: 1.10–1.64, p = 0.003) and increased advanced stage (III + IV) (OR = 1.20, 95% CI: 1.06–1.37, p = 0.004). Conclusions This meta-analysis demonstrated that elevated PLR was a prognostic factor for poor OS and DFS, and associated with clinicopathological parameters in patients with GC.

Background: Pretreatment PLR (platelet-lymphocyte ratio), was reported to be associated with the prognosis in gastric cancer (GC), but the results remain inconclusive. This meta-analysis aimed to investigate the prognostic potential of the pre-treatment PLR in gastric cancer.Methods: We performed a systematic literature search in PubMed, Embase and the Cochrane Library to identify eligible publications. The hazard ratio (HR) /Odds Ratio (OR) and its 95% confidence (CI) of survival outcomes and clinicopathological parameters were calculated.Results: A total of 49 studies (51 cohorts), collectting data from 28,929 GC patients, were included in the final analysis. The pooled results demonstrated that the elevated pre-treatment PLR was significantly associated with poor overall survival (OS) (HR: 1.37, 95% CI: 1.26-1.49, p < 0.001; I2= 79.90%, Ph < 0.001) and disease-free survival (DFS) (HR 1.52, 95%CI 1.22–1.90, P< 0.001, I2= 88.6%, Ph< 0.001). Furthermore, the patients with the elevated PLR had a higher risk of lymph node metastasis (OR = 1.17, 95% CI: 1.02–1.33, p=0.023), serosal invasion (T3 +T4) (OR = 1.34, 95% CI: 1.10–1.64, p=0.003) and increased advanced stage (III+IV) (OR = 1.20, 95% CI: 1.06–1.37, p=0.004).Conclusions: An elevated pre-treatment PLR was a prognostic factor for poor OS and DFS, and associated with poor clinicopathological parameters in GC patients .