Clinicopathological and prognostic significance of circulating tumor cells in head and neck squamous cell carcinoma: A systematic review and meta-analysis

•The first study to estimate the correlation between CTCs and clinical prognosis.•CTCs can be considered as a monitoring tool for prognosis of HNSCC patient.•Positive CTCs is significant associated with survival of patients with HNSCC. The prognostic significance of circulating tumor cells (CTCs) in patients with head and neck squamous cell carcinoma (HNSCC) is still unclear. The objective of this study was to estimate its correlation with clinicopathological and prognostic significance in HNSCC. Two authors systematically searched the studies independently with keywords in PubMed, Web of science, Embase, the Cochrane database, the CNKI database, the Science citation index and the references of relevant studies (up to February 2019). Odds ratio (OR), risk ratio (RR), pooled hazard ratio (HR) and 95% confidence intervals (95%CI) were calculated as effect values. Twenty studies containing 1054 patients with HNSCC were included in this meta-analysis. The CTC-positive rate was higher in the T3-T4 group (RR = 1.29, 95% CI [1.11, 1.49], I2 = 47.3%), the N1-N3 group (RR = 1.18, 95% CI [1.02, 1.36], I2 = 12.4%) and the III-IV group (RR = 1.13, 95% CI [1.02, 1.25], I2 = 0%). Positive CTCs were significant associated with overall survival (HR = 1.37, 95% CI [0.59, 2.15], I2 = 9.7%), progression-free survival (HR = 3.40, 95%CI [1.47, 5.32], I2 = 0%), and disease-free survival (HR = 3.57, 95%CI [1.06, 6.08], I2 = 81%). Our meta-analysis results indicated that CTCs are significant associated with prognosis of patients with HNSCC. The presence of CTCs can be used as a monitoring tool for survival prognosis of HNSCC patients in the future.