My husband was diagnosed with it a few years ago. Think of it as getting a "bad" pap test result. Barrett's is diagnosed via tissue biopsies taken during endoscopy. In a patient with longstanding, severe reflux, the cells of the esophogus begin to change in order to protect itself. Isn't the human body amazing? In response to the continuous burning of stomach acid, the cells begin to mutate into cells that resemble those in the duodenum (the beginning of the small intestine right below the stomach). The duodenum is intended to deal with stomach acid. The esophogus isn't, so it tries to change its own makeup for protection. The problem is, those cells just can't quite do the job.
Yes, given enough time, those cells that have mutated have the potential to keep on mutating until they become cancerous. That is why Barrett's patients should have an endoscopy every year or two to keep up with the degree of cell mutation called dysplasia. There are several degrees of cell dysplasia (identified in the biopsies by a pathologist) before a patient even needs to think of worrying about cancer. Your husband could ask his doctor to explain the pathology report to him in detail for a better understanding of this process.
If a Barrett's patient keeps the reflux under control with diet and PPI meds like aciphex, nexium, protonix, etc., there really is nothing to worry about. In the occasional patient in whom meds don't work, surgery can be done to prevent reflux from happening at all. That procedure is called a Nissen's Fundoplication. The top part of the stomach is "wrapped" around the lower esophogus forming a physical barrier for the refluxing stomach acid. It's obviously not that simple, and sometimes patients have more problems from the surgery, so it's not something you would want to enter into lightly.
Think of the annual endoscopy just like you would an annual pap test. It's just a way to keep an eye on tissue changes at a cellular level. I hope that didn't alarm you as my intent was just the opposite. :-) My husband was scared to death when he was diagnosed, but like gale01, his condition has actually improved over the years with meds and common-sense changes to his diet.
My gastroenterologist at Lahey Clinic told me recently that Barrett's is overhyped at this time. The greatest concern is that you can develop cancer of the esophogus which is not a good cancer to get. However, properly treated with the acid reduction pills and your Barrett's can dissapte quickly. I was diagnosed six years ago and my last endoscopy was my best ever. I do watch what I eat and make sure that I do not eat late at night which for me was anything after 6:30 or so as I just couldn't sleep if I did. I take the medicine if I feel acid coming on and stay away from fatty and heavy foods. I just had my gall bladder out and have read that there may be a correlation. I wouldn't worry but he should follow the rules of taking the medicine and watching what, how much, and when he eats. If he does that the prognosis should be excellent.