Endoscopic surveillance in Barrett's esophagus

Barrett's esophagus (BE), a complication of chronic gastroesophageal reflux disease (GORD), is a condition that is premalignant for adenocarcinoma of the esophagus and esophagogastric junction. Esophageal adenocarcinoma, once an uncommon entity, has been growing rapidly in incidence over the last two decades in several parts of the world. Barrett's esophagus is a change in the esophageal epithelium of any length that can be recognized at endoscopy and is confirmed to have intestinal metaplasia by biopsy (American College of Gastroenterology guidelines). Because of its premalignant nature, it is recommended that patients with BE undergo regular endoscopic surveillance. The recommendation for endoscopic surveillance is based on unproved and controversial assumptions including: 1) the assumption that Barrett's esophagus adversely influences survival; 2) the assumption that endoscopic surveillance can reliably detect early, curable neoplasia in the columnar lined esophagus. Moreover, the low incidence of adenocarcinoma (reported cancer incidence rates in prospective studies on BE range between 0.5% and 1.9%) is used to support an approach of not surveying patients with Barrett's esophagus. Despite these not convincing data, endoscopic surveillance is considered "reasonable" and "desirable" by the gastroenterological associations and consensus meetings. Endoscopic surveillance for cancer in Barrett's esophagus (BE) is performed primarily to seek dysplasia, to prevent the progression to invasive malignancy; however, one of the limitations of using dysplasia is a lack of understanding of its natural history. The efficacy of endoscopic surveillance for Barrett's esophagus is likely to remain unclear for a long time. The American College of Gastroenterology has recommended the following practice guidelines: a) for patients with no dysplasia, surveillance endoscopy is recommended at an interval of every 2 to 3 years; b) for patients with low grade dysplasia, surveillance endoscopy every 6 months for the first year is recommended, followed by yearly endoscopy if the dysplasia has not progressed in severity; c) for patients with high grade dysplasia, two alternatives are proposed after the diagnosis has been confirmed by an expert gastrointestinal pathologist. One alternative is intensive endoscopic surveillance until intramucosal cancer is detected at an interval of every 3-6 months. The other alternative is esophageal resection. In the situation of indeterminate dysplasia, whereas the pathologist can not come to definite diagnosis, control biopsies are proposed after 2 months of adequate acid suppression by means of proton pump inhibition. In all cases, the technique of random, four quadrant biopsies taken every 2 cm in the columnar-lined esophagus for standard histologic evaluation is recommended. Any grossly abnormal areas may be biopsied too. One can expect however that during the next future these protocol will change considering new data on dysplasia detection (biochemical markers, flow cytometry), new techniques to identify dysplasia (chromoendoscopy, endosonography, coherence optical tomography, fluorescence techniques) and development of better ablative techniques. At present a marker other than dysplasia identifying a high risk group for cancer on which to focus endoscopic surveillance has not yet been established.