Prognostic Role of the Circulating Tumor Cells Detected by Cytological Methods in Gastric Cancer: A Meta-Analysis

Abstract

Objective. We performed a meta-analysis of available studies to assess the prognostic value of circulating tumor cells detected by cytological methods for patients with gastric cancer. Methods. Two authors systematically searched the studies independently with key words in PubMed, MEDLINE, EMBASE, Science Citation Index Expanded, and Cochrane Library (from inception to April 2016). The estimated hazard ratio, risk ratio, odds ratio, and their 95% confidence intervals were set as effect measures. All analyses were performed by STATA 12.0. Results. Sixteen studies were included in this meta-analysis. CTCs-high status was significantly associated with poor overall survival (HR=2.23, 95% CI: 1.86-2.66) and progression-free survival (HR=2.02, 95% CI: 1.36-2.99). CTCs-high status was also associated with depth of infiltration (OR = 2.07, 95% CI: 1.16-3.70), regional lymph nodes metastasis (OR = 1.85, 95% CI: 1.26-2.71), and distant metastasis (OR = 2.83, 95% CI: 1.77-4.52). For unresectable gastric cancer patients, CTCs-high status was significantly associated with poor overall survival, progression-free survival, and disease control rate before and during chemotherapy group. Conclusions. Our meta-analysis has evidenced the significant prognostic value of CTCs detected for both PFS and OS in gastric cancer patients. For patients treated with chemotherapy alone, we proved that CTCs detected by cytological method showed a significant prognostic value and poor response to chemotherapy.