Prognostic Role of Circulating Tumor Cells in Patients with Pancreatic Cancer: a Meta-analysis

Background: Isolation and characterization of circulating tumor cells (CTCs) in patients suffering from a variety of different cancers have become hot biomarker topics. In this study, we evaluated the prognostic value of CTCs in pancreatic cancer. Materials and Methods: Initial literature was identified using Medline and EMBASE. The primary data were hazard ratios (HRs) with 95% confidence intervals (CIs) of survival outcomes, including overall survival (OS) and progression free survival/recurrence free survival (PFS/RFS). Results: A total of 9 eligible studies were included in this meta-analysis, published between 2002 and 2013. The estimated pooled HR and 95% CI for OS for all studies was 1.64 (95% CI 1.39-1.94, p<0.00001) and the pooled HR and 95% CI for RFS/DFS was 2.36 (95% CI 1.41-3.96, p<0.00001). The HRs and 95% CIs for OS and RFS/DFS in patients before treatment were 1.93 (95% CI 1.26-2.96, p=0.003) and 1.82 (95% CI 1.22-2.72, p=0.003), respectively. In patients receiving treatment, the HRs and 95% CI for OS and RFS/DFS were 1.37 (95% CI 1.001.86, p=0.05) and 1.89 (95% CI 1.01-3.51, p=0.05), respectively. Moreover, the pooled HR and 95% CI for OS in the post-treatment group was 2.20 (95% CI 0.80-6.02, p=0.13) and the pooled HR for RFS/DFS was 8.36 (95% CI 3.22-21.67, p<0.0001). Conclusions: The meta-analysis provided strong evidence supporting the proposition that CTCs detected in peripheral blood have a fine predictive role in pancreatic patients especially on the time point of post-treatment.