Review article: prevalence of Barrett's oesophagus and metaplasia at the gastro-oesophageal junction.

Barrett's oesophagus, a complication of chronic gastro-oesophageal reflux disease, is the premalignant lesion for oesophageal and gastro-oesophageal junction adenocarcinoma. Described in the 1950s by Norman Barrett, the diagnostic criterion for this lesion has evolved significantly over the last three decades. Endoscopic Barrett's oesophagus requires the recognition of columnar mucosa in the distal oesophagus; documentation of metaplastic tissue is confirmed by random biopsies. Given this changing definition of Barrett's metaplasia, the prevalence rates vary in the literature depending on the diagnostic criteria applied. However, it is generally accepted that approximately 10% of patients with chronic gastro-oesophageal reflux disease will be diagnosed with this condition. There are no population-based studies on the prevalence of Barrett's oesophagus, but emerging data indicate that it may be equally prevalent in asymptomatic individuals. These studies require confirmation. Although the incidence of oesophageal adenocarcinoma is increasing rapidly, it is unclear whether the true incidence of Barrett's oesophagus is increasing at the same time. On the other hand, metaplasia at the gastro-oesophageal junction appears to be distinct from Barrett's oesophagus, is probably not related to chronic gastro-oesophageal reflux disease and is a common finding if routine biopsies are obtained at the gastro-oesophageal junction. This article reviews our current understanding of the diagnosis, definition and prevalence of both of these lesions.