Circulating Tumor Cells as a Biomarker for Preoperative Prognostic Staging in Patients With Esophageal Cancer

We evaluated the prognostic significance of circulating tumor cells (CTCs) in patients with esophageal cancer (EC).Despite the availability of several preoperative diagnostic techniques, accurate pretreatment staging of EC remains challenging.In this single-center, prospective study, peripheral blood samples for CTC analyses were obtained preoperatively from 100 patients who were judged to have resectable EC. CTC detection was performed using the CellSearch System. Data were correlated with clinicopathological parameters and patient outcomes.CTCs were detected in 18% (18/100) of all eligible patients. Patients with CTCs showed significantly shorter relapse-free (P < 0.001) and overall survival (P < 0.001) than CTC-negative patients. Even in patients with lymph node invasion and without distant metastases (pN+, M0, N = 45), CTC detection indicated significantly worse relapse-free (P < 0.001) and overall survival (P = 0.007). Multivariate analyses of eligible patients identified CTCs as a strong, independent, prognostic indicator of tumor recurrence (hazard ratio, 5.063; 95% confidence interval, 2.233-11.480; P < 0.001) and overall survival (hazard ratio, 3.128; 95% confidence interval, 1.492-6.559; P = 0.003).This is the first study to report that CTCs detected by an automated immunomagnetic detection system are independent, prognostic indicators of patients' outcome in EC. Thus, implementation of CTCs may improve accuracy of preoperative staging in EC.