The prognostic role of circulating tumor cells and disseminated tumor cells in patients with ovarian cancer: a systematic review and meta-analysis

Background: Observational studies have demonstrated an association between circulating tumor cells (CTCs) or disseminated tumor cells (DTCs) expression levels and clinical outcomes in patients with ovarian cancer, The purpose of this study was to evaluate the correlation between survival outcome and CTCs or DTCs counts in patients with ovarian cancer. Materials and Methods: A literature search was conducted among PubMed, Embase, and Cochrane library from inception to April 2015. Studies' quality was assessed by Newcastle-Ottawa Scale, the meta-analysis was performed using hazard ratios (HRs), odds ratios (ORs), and 95% confidence intervals (CIs) as effect measures. Subgroup and sensitivity analyses were also performed. Results: Fourteen eligible studies were included. The estimated HRs for the effect of CTCs/DTCs on overall survival (OS) and relapse-free survival (RFS) or disease-free survival (DFS) or progression-free survival (PFS) were 1.91 (1.53, 2.39) and 1.83 (1.47, 2.27), respectively. It did not show significant difference (OR=1.59; 95% CI [0.79, 3.20], p = 0.20) between the detection of CTCs/DTCs and International Federation of Gynecology and Obstetrics (FIGO) stage. Additionally, subgroup analyses indicated strong prognostic powers of CTCs and DTCs, irrespective of methodological, detection time, and sample size differences of the studies. Conclusion: This meta-analysis showed that CTCs and DTCs can predict the survival of ovarian cancer patients. Future studies are needed to determine the best sampling time points and detection methods in these patients.