Prognostic value of circulating tumor cells in patients with bladder cancer: A meta-analysis

BACKGROUND: Circulating tumor cells (CTCs) have been considered diagnostic and prognostic biomarkers for urothelial cancer. However, the prognostic role of CTCs in bladder cancer (BC) remains controversial. Here, we conducted a meta-analysis to evaluate the prognostic significance of CTCs for patients with BC. METHODS: All studies relevant to this topic were searched in the PubMed, Embase, and Web of Science databases. The hazard ratio (HR) and 95% confidence interval (95% CI) were set as effect measures. The outcomes were overall survival (OS), cancer-free survival (CSS), progression-free survival (PFS)/time to progression (TTP), and disease-free survival (DFS)/recurrence-free survival (RFS)/time to first recurrence (TFR). All analyses were conducted in STATA 15.1. RESULTS: Eleven eligible studies comprising 1,062 patients with BC were included in this meta-analysis. Overall analyses showed that CTC-positive patients had poorer survival (OS: HR 3.88, 95% CI 2.52–5.96, p < 0.001; CSS: HR 3.89, 95% CI 2.15–7.04, p < 0.001) and more aggressive progression (PFS/TTP: HR 5.92, 95% CI 3.75–9.35, p < 0.001; DFS/RFS/TFR: HR 4.57, 95% CI 3.34–6.25, p < 0.001) than CTC-negative patients. Subgroup analyses according to the number of patients, detection method, positivity rate, and follow-up time revealed that the presence of CTCs predicted a high risk of mortality and disease progression in most subgroups. CONCLUSION: The meta-analysis confirmed that CTCs are a promising prognostic biomarker of poor survival and aggressive tumor progression for patients with BC. PROSPERO REGISTRATION NUMBER: CRD42021224865.