Barrett esophagus is a change or mutation in the lining of the esophagus from normal squamous epithelium to columnar epithelium.
This abnormal lining is a premalignant change. Prospective studies have determined the risk of developing esophageal adenocarcinoma in the presence of long segment Barrett esophagus is approximately 1:100 patients each year or 1% per year. This translate into a 5-10% lifetime risk of developing esophageal cancer, although no good studies are available that document the lifetime risk of a population of patients with Barrett.
It is thought that the presence of bile from the duodenum refluxing into the esophagus plays an important role in the development of Barrett esophagus.