Circulating Tumor Cells (CTCs) Detected by RT-PCR and Its Prognostic Role in Gastric Cancer: A Meta-Analysis of Published Literature

OBJECTIVE: The prognostic significance of circulating tumor cells (CTCs) is controversial in gastric cancer (GC). We performed a meta-analysis of available studies to assess its prognostic value detected by RT-PCR for patients diagnosed with GC. METHODS: EMBase, PubMed, Ovid, Web of Science, Cochrane library and Google Scholar database search was conducted on all studies reporting the outcomes of interest. The studies were set up according to the inclusion/exclusion criteria. Meta-analysis was performed by using a random-effects model; hazard ratio (HR), risk ratio (RR) and their 95% confidence intervals (95% CIs) were set as effect measures. The information about trial design, results from the data was independently extracted. Heterogeneity of the studies was tested for each pooled analysis. RESULTS: Nineteen studies published matched the selection criteria and were included in this meta-analysis. CTCs positivity was significantly associated with poor relapse free survival (RFS) (HR 2.42, 95% CI: [1.94–3.02]; P<0.001) and poor overall survival (OS) (HR 2.42, 95% CI: [1.94–3.02]; P<0.001). CTCs positivity were also significantly associated with regional lymph nodes (RLNs) metastasis (RR 1.42, 95% CI: [1.20–1.68]; p<0.0001), depth of infiltration (RR 1.51, 95% CI: [1.27–1.79]; p<0.0001), vascular invasion (RR = 1.43, 95% CI: [1.18–1.74], p = 0.0002) and TNM stage(I,II versus III) (RR 0.63, 95% CI [0.48–0.84]; p = 0.001). CONCLUSION: Preoperative CTCs positivity indicates poor prognosis in patients with gastric cancer, and associated with poor clinicopathological prognostic factors.