What is the endoscopic prevalence of short segments of Barrett's esophagus?
A.J. Cameron (Rochester,)
The normal mucosa at the gastroesophageal junction, just below the squamo-columnar junction, is gastric cardiac or junctional epithelium. This does not contain goblet cells.
In patients with a long segment of Barrett's esophagus (BE), greater than three centimeters in length, almost all the columnar mucosa in the esophagus consists of intestinal metaplasia or specialized columnar epithelium, which contains goblet cells and resembles intestinal rather than gastric epithelium. This type of epithelium is associated with an increased risk of adenocarcinoma of the esophagus. So, the question is, how often are small areas or short segments of this type of epithelium found at the lower end of the esophagus, extending upwards for three centimeters or less?
Spechler et al. (1994) drew our attention to this with an article in the Lancet. They examined 142 patients. All had endoscopy and biopsy. In those patients with reflux symptoms, Spechler et al. found intestinal metaplasia on the endoscopic biopsy in 18%. Of great interest, they also found intestinal metaplasia in 19% of those patients having endoscopy for other indications, who did not have reflux symptoms. Clark et al. (1994) found intestinal metaplasia in 24% of 87 patients with reflux, and Abo et al. (1995) found metaplasia in 17% of 64 reflux patients. Dr. Kamath and I found intestinal metaplasia on biopsy in 21% of patients with reflux symptoms and 20% of controls.
In our series, we examined consecutive patients with typical heartburn occurring at least once per week, with symptoms relief by antacids or acid suppressant medications. To reduce bias, we only included patients with no previous endoscopy in their lifetime. We took biopsies just below the squamo-columnar junction in all patients and measured the distance to the Z line, the esophagogastric junction, and the diaphragm in each case.
One hundred and eighty patients had reflux symptoms. Five of these had a long Barrett's, three centimeters or more in length, that is 3%. But, 38 (21%) had intestinal metaplasia with less than three centimeters of visible columnar mucosa, often none. In 20 patients without reflux symptoms acting as controls, 4 (20%) had intestinal metaplasia.
Intestinal metaplasia was about equally common in males as in females, 23% versus 19%. A long Barrett's was found in 4% of males and 1% of females.
The prevalence of intestinal metaplasia, less than three centimeters in length, seemed to increase with age.
It was about 14% in patients from 20 to 39, 22% in patients from 40 to 59, and 26% in patients age 60 to 79 years.
It was difficult to distinguish, at endoscopy, between different types of upward extensions from the Z line. Red tongues could represent variations of the normal Z line with normal cardiac epithelium, or could represent short segments of BE with intestinal metaplasia and areas of superficial ulcerations without exudate could also give a similar appearance. On the other hand, intestinal metaplasia was also found when no Barrett's was suspected by the endoscopist.
When the endoscopy appeared normal, intestinal metaplasia was found in 7%. When the endoscopy showed esophagitis only, intestinal metaplasia was found in 22%. When there was endoscopic evidence of possible short segment Barrett's, intestinal metaplasia was found in only 41%. When the endoscopist observed esophagitis and probable short segment Barrett's, intestinal metaplasia was found in 38%. In the 5 patients with a long Barrett's, more than 3 centimeters, seen on endoscopy intestinal metaplasia was found in all 5, 100%.
Our findings may be summarized as follows.
Biopsies show intestinal metaplasia at the esophagogastric junction in about 20% of patients. The prevalence is similar with or without reflux symptoms. Endoscopic identification of short segments or tongues of Barrett's esophagus is unreliable. Prevalence of intestinal metaplasia is similar in either sex. There is a trend to increased prevalence of intestinal metaplasia with age.