Barrett's Esophagus in the Chinese Population (pp. 139-164)
Authors: (Qin Huang, Department of Pathology and Laboratory Medicine, Veterans Affairs Boston Healthcare System and Harvard Medical School, West Roxbury, MA, USA)
Abstract: At present, Barrett’s esophagus (BE) remains the only proven risk factor for esophageal adenocarcinoma (EAC) that shows the fastest growing incidence in Western countries in recent decades. Although published reports on BE in the Chinese population are scarce in the English literature, a growing body of evidence derived from recent epidemiologic, endoscopic, and clinicopathologic studies with standardized criteria in the Chinese population show intriguing preliminary results. For example, population-based studies demonstrate that BE with intestinal metaplasia is rare in Chinese, ranging from 0.06% in the general population to about 2% in referral patients for upper endoscopy. The common risk factors for BE in patients from Western countries, such as male gender, severe gastroesophageal reflux disease (GERD), and obesity are uncommon in Chinese. Even in Chinese patients with columnar-lined esophagus (CLE, with or without goblet cells), the length of this lesion in up to 97% of patients is shorter than 10 mm and the long-segment lesion > 30 mm is exceptional. This fact mirrors the rarity of EAC in the distal esophagus with an incidence of about 1% in Chinese by both epidemiologic and histopathologic studies. However, CLE of the distal esophagus, diagnosed by histopathology, is very common in Chinese and found in up to 65% of patients with proximal gastric cancer. In these cases, CLE appears to arise in inflamed and hyperplastic superficial esophageal glands and forms short columnar epithelial patches within the predominant esophageal squamous epithelium, unlike BE lesions seen in Western patients. These short columnar patches of CLE in Chinese are associated with chronic inflammation characterized by Helicobacter pylori infection, lymphoplasmacytic infiltrate, lymphoid follicles, intestinal metaplasia, and pancreatic metaplasia. These associated inflammatory diseases are also present in similar or higher frequencies in the adjacent proximal gastric mucosa, suggesting an overflow of chronic inflammation from the proximal stomach into the distal esophagus, which may be the primary cause of BE (or CLE) in these patients. Similarly, cancer in the gastroesophageal junction in Chinese shows features of gastric cancer, not those of EAC. These initial results suggest that BE (or CLE) in Chinese may result from pathogenic mechanisms different from those in Western patients. The clinical significance of BE-related diseases requires further investigation with defined criteria in this population.