The Role of Circulating Tumor Cell Dynamics in the Prognosis of Colorectal Cancer: A Systematic Review and Meta-Analysis.

Objective

The prognostic value of circulating tumor cells (CTCs) in colorectal cancer (CRC) remains debated. This meta-analysis evaluates their role in monitoring treatment response and predicting survival.

Methods

We systematically searched multiple databases up to November 2025. Inclusion criteria comprised cohort studies involving CRC patients that assessed peripheral blood CTCs and reported outcomes such as CTC positivity/levels before and after treatment, progression-free survival (PFS), and overall survival (OS). Two reviewers independently extracted data and assessed the risk of bias using the Newcastle-Ottawa Scale. The meta-analysis was performed using Stata 18.0, with pooled odds ratios (ORs), standardized mean differences (SMDs), and hazard ratios (HRs) calculated using fixed- or random-effects models based on heterogeneity assessed by the I² statistic. This study was registered in PROSPERO.

Results

A total of 18 studies involving 2,838 CRC patients were included. The meta-analysis demonstrated a significant decrease in both the CTC-positive rate (OR=0.52, 95% CI 0.31-0.87) and CTC count (SMD=-0.32, 95% CI -0.42 to -0.21) following therapy. Compared to patients without CTC reduction, those with reduced CTCs exhibited significantly better progression-free survival (HR=2.41, 95% CI 1.75-3.31) and overall survival (HR=3.29, 95% CI 1.99-5.45). Furthermore, CTC-positive status, both before and after treatment, was consistently associated with inferior PFS and OS (all p < 0.0001).

Conclusions

CTCs can serve as a biomarker for monitoring CRC therapeutic efficacy, predicting prognosis, and guiding subsequent treatment.