Clinical Significance of Circulating Tumor Cells in Peripheral Blood of Patients with Esophageal Squamous Cell Carcinoma

BACKGROUND: Esophageal squamous cell carcinoma is an aggressive gastrointestinal tract cancer. To date, the presence of circulating tumor cells (CTC) has been reported as a prognostic factor in peripheral blood from patients with gastrointestinal cancers. METHODS: The CellSearch system was used to isolate and enumerate CTCs. A total of 90 patients with esophageal squamous cell carcinoma who received chemotherapy or chemoradiotherapy were enrolled. Peripheral blood specimens were collected before and after treatments. RESULTS: At baseline analysis, CTCs were detected in 25 patients (27.8 %). Overall survival was significantly shorter in patients with than without CTCs. Follow-up blood specimens were obtained from 71 patients. Partial response, stable disease, and progressive disease after treatment were seen in 32, 12, and 27 patients, respectively. CTC positivity after treatment in the progressive disease group (40.7 %) was significantly higher than that of the partial response group (6.3 %). Patients with a change in CTC status from positive to negative had a good prognosis as well as patients without baseline CTCs. CONCLUSIONS: Evaluation of CTCs may be a promising indicator for predicting tumor prognosis and the clinical efficacy of chemotherapy or chemoradiation therapy in patients with esophageal squamous cell carcinoma. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1245/s10434-015-4392-8) contains supplementary material, which is available to authorized users.