Background: Although several studies have suggested an association between circulating tumor cells (CTC) and prognosis after esophageal cancer surgery, large-scale studies are lacking. The aim of this study was to prospectively examine the correlation between CTC and outcome in a large number of patients who underwent esophagectomy.
Materials and methods: A cohort of 244 patients with squamous cell carcinoma of the esophagus who underwent curative surgery between 2002 and 2007 were prospectively analyzed for CTC before surgery and after the thoracic procedure. Reverse transcription-polymerase chain reaction for CEA and SCC antigen mRNA was used to detect cancer cells in the peripheral blood. CTC was defined as positive when at least 1 tumor marker mRNA was detected.
Results: CTC was positive in 34 patients (13.9%) before surgery and in 41 patients (16.8%) after the thoracic procedure. Multivariate analysis identified tumor depth (hazard ratio [HR], 0.439; 95% confidence interval [95% CI], 0.268-0.722; P = 0.0012), lymph node metastasis (HR, 2.467; 95% CI, 1.436-4.237; P = 0.0011), venous invasion (HR, 1.802; 95% CI, 1.082-3.002; P = 0.0236), and CTC status after the thoracic procedure (HR, 1.647; 95% CI, 1.032-2.629; P = 0.0365) as independent prognostic factors of disease-free survival. The rates of hematogenous (P = 0.0222) and local (P = 0.0464) recurrences were significantly higher in patients with CTC(+) after the thoracic procedure than those with CTC(-) after the thoracic procedure. Responders to neoadjuvant chemotherapy showed less lymphatic invasion and a decreased positive CTC rate after the thoracic procedure than nonresponders.
Conclusions: CTC status after the thoracic procedure is a useful predictor for hematogenous and local recurrences in patients with esophageal cancer.