Cancer risk in Barrett's oesophagus.

(Table is included in full-text article.)Barrett's oesophagus results from the replacement of the normal squamous lining of the oesophagus by a columnar epithelium. It is the sole known premalignant condition for oesophageal adenocarcinoma. The annual cancer incidence of 1% in Barrett's oesophagus, calculated from published series, has been recently considered an overestimation owing to publication bias, and a 0.5% risk was proposed. The prerequisite of the presence of intestinal metaplasia for the diagnosis of Barrett's oesophagus, although widely accepted, is questioned by some authors. How adenocarcinoma incidence is influenced by requiring or not intestinal metaplasia for Barrett's oesophagus diagnosis is unknown. Most of the published studies included only (or preferentially) patients with long segments. Data on adenocarcinoma incidence in short segments (<3 cm) are very scarce, but it is believed to be lower than in long segments. The magnitude of cancer risk influences cost effectiveness of surveillance of Barrett's oesophagus. Frequently, therapeutic intervention is performed when high-grade dysplasia is diagnosed, preventing progression to adenocarcinoma. This could lead to an underestimation of cancer risk in Barrett's surveillance studies.