Barrett’s esophagus occurs when metaplastic columnar epithelium replaces the stratified squamous epithelium. Another way of saying this is if there is any sign of specialized intestinal metaplasia (lining normally found in the intestine) within the esophagus – then we have Barrett’s esophagus. This is a pre-cancerous condition (adenocarcinoma). Cancer will develop after a sequence of changes:
non-dysplastic columnar epithelium -> low grade dysplasia -> high grade dysplasia -> cancer.
It’s important to note that not everyone with GERD will develop Barrett’s esophagus.
This is typically caused by chronic acid reflux. Prolonged exposure of the esophagus to acid reflux eventually erodes the mucosa and ultimately leads to epithelial necrosis.
It is also more prevalent in white males who are over 55 years of age (accounts for 80% of patients). It seems that those who take oral bisphosphonates are also at increased risk.
It’s important to note that Barrett’s esophagus itself does not cause any symptoms. Instead, people are usually evaluated for this because of the reflux symptoms.
Only those with multiple risk factors should be screened – this is to say that all patients who present with typical GERD should NOT be universally screened. Risk factors that predispose to adenocarcinoma:
– chronic GERD (> 5 years)
– hiatal hernia
– over 50 years of age
– male gender
Screening and diagnosis is done with endoscopy. Diagnosis is made when the columnar epithelium lines the distal esophagus and biopsy results must show intestinal metaplasia. If erosive esophagitis is noted then healing of the mucosa is required before a repeat endoscopy is done.
The condition is called long-segment Barrett’s esophagus when the distance between the Z-line and the gastroesophageal junction is ≥3 cm. The Z line is where the lining of the esophagus meets the lining of the intestine. Short-segment Barrett’s esophagus when that distance is <3 cm.
Short segment is the more popular type and typically occurs in those with milder GERD symptoms, are more sensitive to reflux, and have often have a normal lower esophageal sphincter pressure. Those with long segment type typically have more severe and prolonged reflux, weaker lower esophageal sphincter pressures, and are less sensitive to reflux.
Those with short segment are also less likely to turn cancerous – because less mucosa is involved.