Prognostic Significance of Circulating Tumor Cells in Small-Cell Lung Cancer Patients: a Meta-analysis

Circulating tumor cells (CTCs) are believed to be particularly important and a reliable marker of malignancy.However, the prognostic significance of CTCs detected in patients with small cell lung cancer (SCLC) is stillunclear. We therefore aimed to assess the prognostic relevance of CTCs using a meta-analysis. We searchedPubMed for relevant studies and statistical analyses were conducted to calculate the hazard ratio (HR) and95% confidence intervals (CIs) using fixed or random-effect models according to the heterogeneity of includedstudies. A total of 7 papers covering 440 SCLC patients were combined in the final analysis. The meta-analysisrevealed that CTCs were significantly associated with shorter overall survival (HR=1.9; 95%CI: 1.19-3.04;Z=2.67; P<0.0001) and progression-free survival (HR=2.6; 95%CI: 1.9-3.54; Z=6.04; P<0.0001). The resultsthus suggest that the presence of CTCs indicates a poor prognosis in patients with SCLC. Further well-designedprospective studies are required to explore the clinical applications of CTCs in SCLC.