Purpose: Circulating tumor cells (CTCs) are considered potential biomarkers for the detection of hepatocellular carcinoma (HCC). Many studies have attempted to explore this role, but the results are variable. We conducted the first comprehensive meta-analysis to evaluate the diagnostic value of CTC assay for HCC patients. Additional prognostic value was also assessed.
Experimental design: All articles included in our study were assessed using QUADAS guidelines after a literature search. Using bivariate generalized linear mixed model and random-effects model, effect measures such as pooled sensitivity/specificity, positive likelihood ratios/negative likelihood ratios (NLRs), diagnostic odds ratios, hazard ratios (HRs), risk ratios, and corresponding 95% confidence intervals (95% CIs) were calculated. We used receiver operating characteristic curves and area under the curve (AUC) to summarize overall test performance. Heterogeneity, publication bias, subgroup, and sensitivity analyses were also performed.
Results: A total of 2256 subjects including 998 HCC patients in 20 studies were recruited in this meta-analysis. Although the overall diagnostic accuracy of the CTC assay was high (AUC 0.93, 95% CI: [0.90-0.95]), there was a high probability of error rate (NLR 0.33, 95% CI: [0.23, 0.48]). The results were more robust when nonmagnetic-activated isolation was used, compared with magnetic-activated isolation subgroup (NLR: 0.18 vs. 0.41; z = 2.118, P = .034). CTCs positivity was significantly associated with relapse-free survival (HR 2.417, 95% CI: [1.421-3.250]; P < .001), overall survival (HR 3.59, 95% CI: [1.984-6.495]; P < .001), and some clinical characteristics.
Conclusion: CTC assay is not recommended as an independent HCC diagnostic tool, but is associated with poor clinicopathologic characteristics of HCC patients and could indicate poor prognosis.