What is the prevalence of Barrett's esophagus in patients with gastroesophageal reflux and in the general population?
A.J. Cameron (Rochester)
One definition of a Barrett's esophagus (BE) is the presence of 3 cm (some reports use 2 cm) or more of columnar epithelium in the esophagus. In this review, this will be referred to as long segment Barrett's esophagus (LSBE) or as just Barrett's. Intestinal metaplasia at the esophagogastric junction involving less than 2-3 cm of the esophagus will be referred to as short segment Barrett's esophagus (SSBE). It is accepted that this definition is arbitrary, especially in cases where metaplasia is found on biopsy but no columnar epithelium is seen on endoscopy.
Several earlier series reporting the prevalence of BE in patients having endoscopy were reviewed by Phillips and Wong . They found that in patients having endoscopy for any reason, not just reflux symptoms, the prevalence of Barrett's was 0.3-2%. Among patients with reflux symptoms, the prevalence of BE was 8-20%. These earlier series probably do not accurately reflect the general population prevalence of Barrett's. For example, the indications for endoscopy were usually not stated, and sampling bias may have resulted in overestimating the prevalence of Barrett's. On the other hand there may have been under-reporting in retrospective series collected at a time when Barrett's was less often recognized at endoscopy than now.
Two prospective studies studied the prevalence of Barrett's in subjects with reflux symptoms. Winters et al.  performed endoscopy in 97 patients with any 2 of heartburn, regurgitation or dysphagia occurring at least once a week. Twelve (12%) had LSBE with 3 cm or more of columnar esophageal lining. However, only 6 patients (6%) had intestinal metaplasia on histology, and the diagnosis might be questionable without this confirmation. The study was done at a naval hospital, presumably mostly males. Mann et al.  took biopsies in 180 male patients with reflux symptoms 2 and 4 cm above the LES and found 20 (11%) had LSBE. Again, only 12 (7% of the total) had intestinal metaplasia.
Adenocarcinoma of the esophagus usually arises in a BE. It is now recognized that adenocarcinoma of the esophagogastric junction frequently arises in Barrett's intestinal metaplasia, either in long or short segments [4, 5]. Recent studies have examined the incidence of SSBE. In an important paper, Spechler et al.  measured the length of columnar epithelium in the distal esophagus and took biopsies from 142 patients having endoscopy for various indications, with no previous diagnosis of BE. Only 2 new cases (1.4%) of LSBE were found, but 26 (18%) had intestinal metaplasia at the gastroesophageal junction on biopsy. Of special interest, intestinal metaplasia was equally prevalent in patients with or without esophageal reflux symptoms. These findings have been confirmed by others. Clark et al.  biopsied the gastroesophageal junction in 87 patients with reflux symptoms. Intestinal metaplasia was found in 21 (24%). Abo et al.  did endoscopy in 64 patients with reflux symptoms. Three per cent had LSBE and 17% had SSBE. Nandurkar et al.  examined 130 consecutive patients having endoscopy for various indications. Three per cent had LSBE and 31% had SSBE. Reflux symptoms were similar in those with or without SSBE. We have extended our series . To reduce sampling bias, patients were excluded if they had a previous endoscopy in their lifetime. One hundred eighty patients with typical reflux symptoms had endoscopy and biopsy. Three per cent had LSBE and 21% had SSBE. Twenty per cent of 20 controls without reflux symptoms had SSBE.
In brief, recent data suggests that the prevalence of LSBE in patients with reflux symptoms is 3-6%, rather than the 11-12% in earlier reports. About 20% of patients having endoscopy, with or without reflux symptoms, have histological evidence of intestinal metaplasia at the gastroesophageal junction. This may reflect the prevalence of small areas of intestinal metaplasia in the general middle aged and elderly population, although direct proof of this is lacking
We have previously reported our study of the prevalence of LSBE in a defined population, Olmsted County, Minnesota,where the Mayo Clinic is located [11, 12]. The clinically diagnosed prevalence of Barrett's esophagus was 22.6 cases per 100,000 population. These were persons living in the county, in whom the diagnosis had been previously made by endoscopy and biopsy. At the same time, we did an autopsy study. We found 7 cases of LSBE in 733 consecutive autopsies. Taking autopsies performed on residents of the county, and adjusting for age and sex, we estimated that the true prevalence of LSBE was 376 cases per 100,000 population. We concluded that only about 1 in 20 cases of LSBE had been clinically diagnosed at that time. It was found, however, that the clinically diagnosed prevalence had risen steadily over the years, in parallel with the increased use of diagnostic endoscopy in this population.
In a study of over 50,000 patients having endoscopy , we found that LSBE was rare in childhood, and that the prevalence rose with age up to the age of about 60, consistent with an acquired disorder. The prevalence in males was twice that in females. The length of columnar epithelium in the esophagus did not change with age.
2. Winters C, Spurling TJ, Chobanian SJ, Curtis DJ, Esposito RL, Hacker JF, Johnson DA, Cruess DF, Cotelingam JD, Gurney MS, Cattau EL. Barrett's esophagus. A prevalent, occult complication of gastroesophageal reflux disease. Gastroenterology 1987;92:118-124.
7. Clark GWB, Ireland AP, Chandrasoma P, DeMeester TR, Peters JH, Bremner CG. Inflammation and metaplasia in the transitional epithelium of the gastroesophageal junction: a new marker for gastroesophageal reflux disease. Gastroenterology 1994;106:A63.
8. Abo SR, Stevens PD, Abedi M, Green PHR, Lightdale CJ, Bezwada H, Rotterdam H, Garcia-Carrasquillo RJ, Siegel LM. Prevalence of short-segment Barrett's epithelium in patients with gastroesophageal reflux disease. Gastroenterology 1995;108;A43.
11. Cameron AJ, Zinsmeister AR, Ballard DJ, Carney JA. Prevalence of columnar-lined (Barrett's) esophagus. Comparison of population-based clinical and autopsy findings. Gastroenterology 1990;99:918-922.