Circulating micrometastases of esophageal cancer detected by carcinoembryonic antigen mRNA reverse transcriptase-polymerase chain reaction: clinical implications

In some patients without distant metastases according to conventional preoperative investigations, relapse occurs in distant organs within a few years after radical resection of esophageal cancer. Various attempts have been made to detect micrometastases that are not found by conventional techniques. A quantitative real-time reverse-transcriptase polymerase chain reaction was used to detect messenger RNA for carcinoembryonic antigen in 147 blood samples from 49 patients scheduled for radical resection of esophageal cancer at Juntendo University Hospital between September 2003 and June 2004. The number of circulating cancer cells was assessed and the clinical significance of detecting such micrometastases was analyzed. Multivariate analysis showed that positivity of this assay was significantly associated with pT1 or pT2 disease and stage III or stage IV disease. Patients with more than 40-50 carcinoembryonic antigen mRNA copies among 10(4) normal cells on quantitative analysis had a higher recurrence rate. The number of tumor cells circulating in the blood may have more influence on the prognosis of esophageal cancer than the presence of tumor cells.