In Barrett's esophagus, normal tissue lining the esophagus changes to tissue that resembles the lining of the intestine, explains WebMD. About 10 percent of people with chronic symptoms of GERD develop Barrett's esophagus. Barrett's esophagus increases the risk of developing esophageal adenocarcinoma, which is a serious, potentially fatal cancer of the esophagus. Less than 1 percent of people with Barrett's esophagus develop this particular cancer. Individuals at greatest risk for developing Barretts esophagus are white males who have had long-term GERD, the onset of GERD at a younger age, and a history of current or past smoking.
Sources: webmd.com, webmd.com