Prognostic Value Of Platelet To Lymphocyte Ratio In Peripheral Blood Of Patients With Colorectal Cancer

Background:Growing evidence indicates that inflammation plays an important role in cancer progression and prognosis;however,the prognostic role of platelet to lymphocyte ratio(PLR)in peripheral blood of colorectal cancer(CRC)is unknown.The present study aimed to assess the prognostic ability of PLR and explored the optimal cut-off value of PLR for predicting prognosis in CRC.Methods:A cohort of 1845 CRC patients from the Department of Surgical Oncology at The First Hospital of China Medical University(CMU-SO)was retrospectively analyzed.Harrell's concordance index(c-index)was used to determine the optimal cut-off value of PLR and evaluate its predictive ability,multivariate analysis was conducted to find the values of PLR in predicting the long-term outcomes.A meta-analysis was conducted in this study,articles were identified by searching PubMed,Embase,and Web of Science databases.We extract the characteristics of the include studies,and the outcomes measure included overall survival(OS),disease-free survival(DFS)and clinicopathological characteristics.We used hazard ratio(HR),odds ratio(OR)and 95%confidence intervals(95%CIs)to calculate the effect measures and Review Manager software version 5.3 to perform the statistical analysis.Q test and I~2 test were used to evaluate heterogeneity,and the P values>0.1 and I~2<50%,we used a fixed-effects model to analysis the data.Otherwise,the P values<0.1 and/or I~2>50%indicated significant heterogeneity,we used a random-effects model.Forest plots were used to show the pooled results of Fisher's z values and HRs,and a funnel plot,Begg's test and Egger's test was utilized to test for publication bias between include studies.Results:Our results from CMU-SO indicated that the OS rate was significantly lower in the high-PLR group compared with the low-PLR group(P=0.001).A similar result was observed for the cancer-specific survival(CSS)rate between these two groups(P=0.001).The multivariate analysis indicated that high PLR was an independent prognostic indicator of poor OS(HR=1.356,95%CI=1.117–1.647,P=0.002)and CSS(HR=1.364,95%CI=1.111–1.675,P=0.003).In addition,the c-indexes of TNM staging combined with PLR were greater than those of TNM staging alone(OS:0.768 vs.0.732;CSS:0.785vs.0.746).The results of the meta-analysis of 30 studies were similar to those of the result from CMU-SO.Elevated PLR was significantly associated with poor prognosis of OS(HR=1.48,95%CI=1.33-1.64,P<0.001)and DFS(HR=1.51,95%CI=1.22–1.87,P<0.001).Conclusion:In conclusion,elevated PLR is a negative prognostic indicator of CRC and may serve as an additional index of the current TNM staging system for predicting CRC.