The Significant Prognostic Value Of Baseline Circulating Tumor Cells Detected By CellSearch System In Small Cell Lung Cancer:A Meta-analysis

PURPOSE:Circulating tumor cells(CTCs)are considered as valuable predictors and prognostic biomarkers in the development of different types of malignancies.There is growing evidence that circulating tumor cells(CTCs)play important roles in the development of small cell lung cancer(SCLC).However,the potential value of circulating tumor cells(CTCs)in the prognosis of small cell lung cancer(SCLC)remains to be elucidated.Therefore,the objective of this study was to use a meta-analysis to assess the potential value of prognosis between baseline circulating tumor cells(CTCs)and small cell lung cancer(SCLC).METHODS: We searched PubMed,the Web of Science database as well as references for inclusion in the study,and we retrieved the study until December 2017.We collected datas on the relative prognostic significance of using CellSearch System to detect baseline circulating tumor cells(CTCs)in small cell lung cancer(SCLC).The primary outcome measures were progression-free survival(PFS)and overall survival(OS).The Newcastle-Ottawa Quality Assessment Scale(NOS)was used to assess the quality of each study.Based on the heterogeneity of the included studies,statistical analyzes using either fixed or random effects models were performed to calculate the hazard ratio(HR)and 95%confidence interval(95% CI).We also conducted subgroup analysis,sensitivity analysis and publication bias related assessment.RESULTS: A total of 7 studies covering 496 patients with small cell lung cancer were included in this meta-analysis.The pooled results show that highly expressed circulating tumor cells(CTCs)have adverse effects on the progression-free survival(PFS)of small cell lung cancer(SCLC)(3 studies,HR = 2.03,95% CI: 1.34-3.07,P = 0.0008);whereas for the overall survival(OS),this meta-analysis did not show a significant correlation(7 studies,HR = 1.16,95% CI: 0.58-2.32,P = 0.67).In addition,we also performed subgroup analyzes of circulating tumor cells(CTCs)cut-off value,number of cases and geographic regions.This meta-analysis did not show significant heterogeneity among investigators.P values for subgroup differences were> 0.05.Finally,we analyzed the correlations between circulating tumor cells(CTCs)and clinicopathological parameters.The results showed that highly expressed circulating tumor cells(CTCs)were not found to be associated with tumor stage,but significantly correlated with Performance Scorce(PS),Age and distant metastasis,P value <0.05.CONCLUSIONS:We provide strong evidences that the expression of circulating tumor cells(CTCs)is an independent predictor of prognosis in small cell lung cancer(SCLC).Our study shows that high levels of circulating tumor cells(CTCs)suggest poor prognosis in patients with small cell lung cancer(SCLC),and circulating tumor cells(CTCs)may be potential targets for the treatment of small cell lung cancer(SCLC)in the future.