[Barrett's esophagus]

Barrett's esophagus (BE) has recently gained the interest of Japanese physicians. In BE, the squamous epithelium of the distal esophagus is replaced by metaplastic columnar epithelium. This intestinal metaplasia usually occurs as a complication of severe reflux esophagitis and its association with adenocarcinoma of the esophagus is well established. In 1950 Norman Barrett described a tubular, intrathoracic structure that appeared to be the esophagus, except that the distal portion was lined with columnar epithelium. Although he believed that the distal portion was not the esophagus, the condition in which the distal esophagus is lined with columnar epithelium became known as BE. From animal and clinical studies, the intestinal metaplasia is generally believed to arise from multipotential stem cells located in the basal layer of the squamous epithelium and at the base of the glandular epithelium. Evidence for a genetic basis underlying the dysplasia-adenocarcinoma sequence is now being accumulated. It is known that gastric acid reflux as well as bile reflux can cause distal esophagitis. Therefore, treatment with a proton pump inhibitor alone may not be sufficient therapy for all patients. Antireflux surgery can cause regression of BE in up to 50% of patients. Overall 1-, 2-, and 5-year survival rates for patients with adenocarcinoma arising from BE after surgical resection is reported to be 63%, 41%, and 32%, respectively. Therefore, endoscopic surveillance of patients with BE is suggested.