Prognostic significance of circulating tumor cells in patients with advanced esophageal cancer

Introduction: The purpose of this study was to establish the clinicopathological significance of circulating tumor cells (CTCs) in patients with advanced or recurrent esophageal cancer who received either chemotherapy or chemoradiotherapy. Methods: CTCs from 38 patients with advanced or recurrent esophageal cancer were quantified using the CellSearch system before and approximately 3–5 weeks after the initiation of a new line of chemotherapy or chemoradiotherapy. The correlation between CTC counts and clinicopathological variables was examined. Results: Of the 38 patients, 15 (39 %) had recurrent esophageal cancer, and 23 patients (61 %) had primary advanced esophageal cancer. The mean age was 63 years (range 43–87 years). One patient (2.6 %) had a complete response to treatment, 16 (42.1 %) had a partial response, 12 (31.6 %) showed stable disease, and nine (23.7 %) showed signs of progressive disease. The overall survival of patients with ≥2 CTCs was significantly shorter than that of patients with <2 CTCs both at baseline and at first follow-up (p = 0.047 and p = 0.011, respectively). Significant correlation was found between the change in CTC counts and the response to treatment (p = 0.036). The overall survival in patients with ≥2 CTCs both at baseline and at first follow-up was significantly shorter than patients with <2 CTCs both at baseline and at first follow-up (p = 0.002). Patients with a reduction rate in the CTC value <80 % experienced significantly shorter survival than patients with a reduction rate of ≥80 % (p = 0.035). The CTC counts at first follow-up served as an independent prognostic factor (p = 0.011). Conclusions: Our results suggest that measuring the number of CTCs in patients with advanced or recurrent esophageal cancer can be useful for predicting the survival of patients and for monitoring the response to cancer treatments.