Prognostic value of circulating tumor cells in patients with recurrent and metastatic colorectal cancer: a systematic review and meta-analysis

BACKGROUND: The detection of circulating tumor cells (CTCs) has been employed in prognosticating the likelihood of recurrence and metastasis in colorectal cancer (CRC). Nonetheless, the findings remain enigmatic. This meta-analysis aims to systematically assess the predictive utility of CTCs detection in postoperative recurrence and metastasis among CRC patients. METHODS: A comprehensive search of PubMed, Web of Science, China National Knowledge Infrastructure (CNKI), and Cochrane Library was conducted from inception to March 2023. Pooled estimates including sensitivity, specificity, positive and negative likelihood ratios, diagnostic odds ratio, and summary receiver operating characteristic curve were computed to gauge the predictive value. The QUADAS-2 tool was employed to appraise bias risks in individual studies. The assessment of publication bias in the included literature was performed using Deek's funnel plot. RESULTS: The study encompassed 16 articles and 2037 patients. After synthesizing the pertinent indices, CTCs monitoring demonstrated sensitivity and specificity of 0.71 (95% confidence interval [CI], 0.62-0.79) and 0.71 (95% CI, 0.55-0.83), respectively. The corresponding values for positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were 2.4 (95% CI, 1.5-4.0), 0.41 (95% CI, 0.29-0.58), and 6 (95% CI, 3-13). The summary receiver operating characteristic curve yielded an area under the curve of 0.76 (95% CI, 0.72-0.80). Deek's funnel plot analysis revealed no significant evidence of publication bias (P = .42). CONCLUSION: This investigation underscores the potential of CTCs detection as a noninvasive modality to efficaciously prognosticate postoperative recurrence and metastasis in CRC.