This article was last reviewed and updated on May 3, 2019.
by Shaheed Hakim, MD FRCPC
Barretts esophagus is a non-cancerous condition where some of the cells that cover the inside of the esophagus have changed to look like the cells that normally cover the inside of the small bowel (the duodenum).
Barretts esophagus is often caused by long standing acid reflux disease (GERD).
It is a non-cancerous condition but it does increase the risk for developing a cancer of the esophagus called adenocarcinoma.
The normal esophagus
The esophagus is a long hollow tube that starts at the back of your throat and ends at the top of your stomach. Swallowed food travels down the esophagus into the stomach.
The inside of the normal esophagus is covered by special cells called squamous cells which form a layer on the inner surface of the esophagus called a epithelium. Squamous cells are very good at protecting tissue against physical forces such as food sliding down your esophagus on its way to your stomach.
Acid reflux disease
People with acid reflux disease (also known as gastroesophageal reflux disease or ‘GERD’ for short) experience pain when the acids in their stomach move backwards into the esophagus. Squamous cells unfortunately are not as good at protecting tissue against the strong acids in your stomach.
If the acid reflux continues over a long period of time (usually years), the squamous cells that line the esophagus become injured and a new type of epithelium slowly replaces the squamous epithelium. This new type of epithelium is very similar to the epithelium of the small intestine and is made up of cells that are designed to protect tissue from the strong acids in the stomach. The change from squamous epithelium to small intestinal epithelium is an example of intestinal metaplasia.
What is Barretts esophagus?
The new epithelium is made up primarily of two types of cells, columnar cells and goblet cells. A diagnosis of Barretts esophagus means that your pathologist saw both of these types of cells after examining tissue taken from your esophagus under the microscope.
Barretts esophagus is a non-cancerous disease, however, it is considered a pre-cancerous condition to a cancer in the esophagus called adenocarcinoma.
Importantly, the risk of developing cancer after a diagnosis of Barretts esophagus is low. The presence of dysplasia, a type of abnormal cell growth, in Barrett's esophagus increases the risk of cancer and your pathologist will carefully examine the tissue for any evidence of dysplasia (see Dysplasia below).
Barretts esophagus is almost always diagnosed first on a biopsy. The biopsy is usually performed because the patient has symptoms consistent with acid reflux disease. The diagnosis may also be made on a resection specimen such as an endoscopic mucosal resection.
Long standing Barretts esophagus is a risk factor for developing a change called dysplasia. Because of this risk, your pathologist will carefully examine your tissue sample for dysplasia and will include it in your pathology report if it is seen.
Dysplasia is a word pathologists use to describe an abnormal pattern of growth that starts as a non-cancerous (benign) change but can turn into cancer over time. Not all tissues with dysplasia will turn into cancer and most tissues go through other changes before there is any evidence of cancer.
The earliest type of dysplasia is called low grade dysplasia. The cells in low grade dysplasia are darker and larger than normal cells. In some cases the cells become even more abnormal and change to high grade dysplasia. The cells in high grade dysplasia look very similar to cancer cells but they are only seen in epithelium on the inner surface of the esophagus.
Although Barretts esophagus is considered a non-cancerous (benign) disease, the presence of dysplasia, in particular high grade dysplasia, increases the risk that a cancer in the esophagus called adenocarcinoma will develop in the future. For this reason, Barretts esophagus with dysplasia is considered a pre-cancerous or precursor disease.
A margin is normal tissue that surrounds an area of abnormal tissue and is removed with the abnormal tissue at the time of surgery. When a part of the esophagus is removed to treat Barretts esophagus, the surgeon will try to remove a small amount of normal esophagus (or sometimes stomach) to ensure that no abnormal tissue is left behind.
High grade dysplasia close to or at the cut edge of the tissue is associated with a higher risk of the disease coming back in the future.