The prognostic role of circulating tumor cells in gastric cancer: A meta-analysis

Objective: We conducted a meta-analysis to evaluate the relationship between circulating tumor cells (CTC) and the prognosis of patients with gastric cancer. Materials and methods: The cohort studies reporting on the relationship between CTC and prognosis of gastric cancer were collected from Pubmed, Cochrane, Embase, CNKI, WanFang Data, and VIP databases. The two researchers independently screened the literature, extracted the data, and evaluated the bias risk of the included literature. The data were analyzed by Revman software (Review Manager version 5.4). Result: A total of 14 retrospective cohort studies with 1053 patients were included. The results showed that the overall survival time (OS) and progression-free survival time (PFS) of CTC-positive patients were shorter compared to CTC-negative patients. Taking into consideration the critical value of CTC positive patients, country of origin, sample size, treatment mode, and study time, the subgroup analysis showed that CTC-positive was related to the shortening of OS in patients with gastric cancer. Based on the subgroup analysis of the factors such as CTC positive critical value < 2.8, sample size > 75, mixed therapy, longer study duration, country, and immunofluorescence detection of CTC, it was found that OS in CTC positive group was shorter than that in CTC-negative group (all P < 0.05), while the critical value of positive CTC > 2.8, sample size > 75, choice of treatment only for operation or non-operation, short study time and molecular detection of CTC were not associated with OS (all P > 0.05). In addition, CTC-positive patients had a more advanced TNM staging, poorer tumor differentiation, and earlier distant metastasis. Conclusion: CTC can be used as a prognostic indicator of gastric cancer. Gastric cancer patients with positive CTC may have a poorer prognosis compared to those with CTC-negative tumors.