Algor4Itmo

Seminar

Barrett’s oesophagus
Nicholas J Shaheen, Joel E Richter
Lancet 2009; 373:850–61 Center for Esophageal Diseases and Swallowing, Division of Gastroenterology and Hepatology, University of North Carolina School of Medicine, NC, USA (N J Shaheen MD) and Division of Gastroenterology, Department of Medicine, Temple University School of Medicine, Philadelphia, PA, USA (Prof J E Richter MD)Correspondence to: Dr Nicholas Shaheen, CB#7080, UNC-CH, Chapel Hill, NC 27599, USA nshaheen@med.unc.edu

Barrett’s oesophagus is a metaplastic change of the lining of the oesophagus, such that the normal squamous epithelium is replaced by specialised or intestinalised columnar epithelium. The disorder seems to be a complication of chronic gastro-oesophageal reflux disease, although asymptomaticindividuals might also be affected, and it is a risk factor for the development of oesophageal adenocarcinoma, a cancer with rapidly increasing incidence in developed societies. We review the presentation, epidemiology, and risk factors for this condition. We discuss the molecular changes necessary for the development of Barrett’s oesophagus and its progression to cancer, and new strides in boththe endoscopic detection of the lesion and the treatment of dysplastic disease. Also, we assess the effectiveness of efforts to screen patients at risk of Barrett’s oesophagus, and whether such efforts avert cancer death. We conclude with a discussion of future directions for research, focusing on treatment of early neoplasia, and modifications of current practices to show our evolving understanding ofthis condition.

Introduction
Barrett’s oesophagus is a metaplastic change of the lining of the oesophageal mucosa, such that the normal squamous epithelium is replaced with specialised or intestinalised columnar epithelium.1,2 Intestinal metaplasia is clinically significant because it is associated with heightened risk of oesophageal adenocarcinoma, which has substantially increased inincidence in developed populations. Barrett’s oesophagus is associated with symptoms of chronic gastro-oesophageal reflux disease (GERD), such as heartburn and regurgitation.3 This association led to calls for routine upper gastrointestinal endoscopy for all patients with chronic GERD to detect Barrett’s oesophagus and prompt subsequent surveillance endoscopies to assess progression to cancer.4 Althoughsuch an approach is intuitively appealing, how well screening and surveillance endoscopy works is uncertain, and the associated costs are large and poorly described.5

Clinical presentation
The diagnosis of Barrett’s oesophagus should satisfy two criteria.6,7 First, examination by upper endoscopy should show cephalad displacement of the squamocolumnar junction. Normally, the squamocolumnarjunction should coincide with the most distal extent of the tubular oesophagus (figure 1A). The intersection of the squamous epithelium of the tubular oesophagus (figure 1B) and the columnar epithelium of
Search strategy and selection criteria We searched Medline (1950–March, 2008), the Cochrane Library (1993–March, 2008), and Embase (1966–March, 2008) using the search terms “Barrett’s esophagus” or“Barrett esophagus”, “specialized epithelium”, “columnar-lined esophagus”, and “intestinalized epithelium”. We also searched for “esophageal adenocarcinoma” and “adenocarcinoma of the esophagus” combined with the terms “prevention”, “pathogenesis”, “pathophysiology”, “diagnosis”, and “epidemiology”. No language restrictions were placed on the searches. We focused on original contributions, systematicreviews, and meta-analyses published in the past 5 years, but we also included reviews, editorials, and older publications that we judged to be relevant. We searched the reference lists of selected articles identified by the search strategy. The date of the last search was November, 2008.

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