Platelet To Lymphocyte Ratio In Peripheral Blood And Body Mass Index:Novel Independent Prognostic Factors In Patients With Melanoma

Background and PurposeIn recent years,increasing evidences have demonstrated that the inflammatory response plays a pivotal role in different stages of tumor progression,including initiation,proliferation,invasion,metastasis and angiogenesis.Many studies have shown that the function of platelet is not only confined to the coagulation process,it is also a special type of inflammatory cell and immune cell.It regulates the body’s inflammatory response and immune response through a variety of mechanisms,and plays an important role in tumor initiation,invasion and metastasis.The amount of platelets shall reflect the invasive potential of cancer cell to some extent.High platelet count can promote the progression of many kinds of tumors and is closely related to the poor prognosis.Lymphocytes are major components of immune system,playing an extremely important role in the body’s antitumor immune response.Abnormalities in lymphocyte,whether function or quantity,can cause immunodeficiency,and thus promote the initiation and progression of tumors.A number of studies have confirmed that platelet to lymphocyte ratio(PLR)in peripheral blood as a novel inflammatory index is an independent risk prognostic factor of multiple tumors.However,to the best of our knowledge,the prognostic value of PLR in melanoma has not yet been reported.Recent studies have also shown that body mass index(BMI)is also associated with the prognosis of tumors,and can be used as a prognostic indicator.The purpose of this study was to investigate the relationship between pre-treatment PLR,BMI and overall survival(OS)of patients with melanoma in order to provide some help for clinical treatment.MethodsClinical date of 140 patients with melanoma in the Affiliated Cancer Hospital of Zhengzhou University and Henan Cancer Hospital from January 1,2010 to December31,2015 were analyzed retrospectively.Receiver operating characteristic(ROC)curve was performed the optimal cut-off value for PLR.The 140 patients were divided into high PLR group and low PLR group.According to"Guidelines for prevention and control of overweight and obesity in Chinese adults",the patients were divided into high BMI group and low BMI group.The relationship between PLR,BMI with overall survival(OS)was analyzed.The Kaplan-Meier method and Log rank test was used for univariate survival analysis and Cox proportional hazards regression model for multivariate analysis.ResultsThe optimal cut-off value of PLR determined by ROC curve was PLR=120.15,and BMI threshold was 24Kg/m~2.Univariate survival analysis showed that PLR,BMI and clinical stage were the factors affecting the OS in patients(P<0.05).The overall media survival time(MST)was 21.0 months(95%confidence interval(CI):18.1-23.9),for 17.0 months in the high PLR group,and 34.0 months in the low PLR group(hazard ratio(HR):0.436,95%CI:0.291-0.652,P<0.001).The MST in the high and low BMI group was 29.0 months and 13.0 months(HR:2.040,95%CI:1.436-2.900,P<0.001),respectively.Cox multivariate analysis showed that PLR,BMI and clinical stage were independent prognostic factors of OS(P<0.05).And BMI was the only independent protective factor for OS,the risk of death decreased by0.582 times,with each unit increased for BMI.Clinical subgroup analysis showed that PLR also was risk factor to the prognosis of patients with stage II,III,and IV(P<0.05).ConclusionsPLR is an independent prognostic risk factor for patients with melanoma,and BMI is an independent protective factor.PLR and BMI are important factors in prognostic evaluation of melanoma.