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What is Barrett's Esophagus?

Atabeygi | Nov 23, 2009 |

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Barrett's esophagus is a pre-cancerous lesion in the esophagus caused by exposure to long standing acid reflux.

The cells that line the cavities or structures of the body are known as epithelial cells and these cells can have different shapes based on the function that they must perform. In the esophagus, these cells are flattened and stacked on top of each other; this is known as stratified squamous epithelium. Since they do not need to secrete any substances or perform any other function, except allow the easy passage of food and liquids, this type of epithelium is well suited for the esophagus.

However, in the intestinal tract, starting with the stomach and moving forward, the epithelial cells have many absorptive and secretory functions and so have a different structure. These cells are aligned in a single row and are shaped like columns, so they are known as simple columnar epithelium. The epithelial cells in the stomach produce and excrete stomach acid, digestive enzymes, and mucous to protect themselves from the acid environment they have produced in the stomach.

In long standing acid reflux there is chronic irritation of the epithelial cells in the esophagus through improper relaxation of the sphincter that separates the esophagus and the stomach and from over secretion of acid. The squamous epithelium in the esophagus is not suited to protect itself against the acid exposure and over time it begins to change shape so as to better tolerate the constant irritation. The squamous epithelium starts to turn into columnar epithelium, just like the epithelium found in the stomach. This process, where one cell type turns into another cells type that is normally found in the body, is know as metaplasia.

Over time the metaplastic cells, if they continue being damaged, can undergo further change towards abnormal, immature cells. This is known as dysplasia. The next step after dysplasia is the development of cancerous cells, a process known as neoplasia. Barrett's esophagus is linked to an increased risk of adenocarcinoma of the esophagus, quantified as 0.5% per patient year. This means that for every year Barrett's esophagus is present, the risk of cancer is increased by 0.5%.

Barrett's esophagus is diagnosed by endoscopy and is usually biopsied to look for cancerous changes. Since it is a direct cause of Barrett's esophagus, gastroesophageal reflux disease must be identified and treated early and adequately. Even if Barrett's esophagus is present, treatment of the underlying acid reflux will stop further damage to the cells and this may help reduce the possibility of dysplastic changes.