Heartburn is a burning sensation felt behind the breastbone and sometimes in the neck and throat. It is caused by stomach acid refluxing or splashing up into the esophagus—the muscular tube that connects the throat to the stomach. At the lower end of the esophagus, where it enters the stomach, there is a strong muscular ring called the Lower Esophageal Sphincter (LES). The LES should remain tightly closed, except to allow food and liquid to pass into the stomach. Heartburn occurs when the LES opens at the wrong time.
Almost everyone has this occasionally, and it is nothing to be concerned about. However, heartburn that is severe or that occurs over a long period of time can be harmful. This is known as Gastroesophageal Reflux Disease (GERD). If GERD is untreated, there is constant acid irritation to the lining of the esophagus, and complications can occur. About 1 in 10 patients with GERD are also found to have a condition called Barrett's esophagus. It can be serious and may lead to cancer of the esophagus.
What is Barrett's Esophagus?
The cells lining the esophagus differ from those lining the stomach or intestines, mainly because they have different functions. They also have a distinctly different appearance, so it is easy for a physician to tell them apart when examining the esophagus and stomach. Normally, there is an area at the end of the esophagus that marks the border between the cells of the esophagus and those of the stomach. Barrett's esophagus is the abnormal growth of stomach or intestinal-type cells above this border, into the esophagus. The Barrett's tissue may spread evenly up into the esophagus, or it may be present as islands or finger-like projections. Usually it is found in the lower portion of the esophagus. However, it may extend throughout the esophagus, or even be found by itself in the middle or upper esophagus.
Since the cells lining the stomach are accustomed to contact with acids, their growth into the esophagus may actually be a defense mechanism. It is designed to protect the normal tissue in the esophagus against further damage by GERD. This may explain why the symptoms of GERD seem to lessen in some patients with Barrett's esophagus. Unfortunately, these tissue changes may be a forerunner of cancer of the lower esophagus, known as adenocarcinoma. Cancer of the upper esophagus (squamous cell cancer) is usually related to alcohol and smoking. This type of cancer appears to be decreasing in the population, while the rate of adenocarcinoma is increasing sharply, especially in white males.
After many years, the Barrett's cells in some patients may develop abnormal changes known as dysplasia. These changes may be in the size or appearance of cells, or in the way the cells grow. Over a period of perhaps two to five years, the dysplasia may progress from low grade, to moderate, to high grade, and finally to cancer. Fortunately, this happens only in about 5% of patients with Barrett's esophagus.
Causes and Symptoms
For unknown reasons, Barrett's esophagus is found three times more often in males than in females. In some instances, Barrett's esophagus appears to be congenital (present at birth). However, current evidence is strong that in most instances, it develops as a result of chronic or longstanding GERD.
In most cases, patients with Barrett's would have symptoms similar to those produced by chronic GERD. Some Barrett's patients may also suffer from other complications of GERD, such as peptic ulcers and stricture—narrowing of the esophagus that comes from scarring. GERD patients with excess acid production or frequent reflux of bile are more likely to develop Barrett's esophagus. This is why it is important for patients with frequent or severe heartburn to see their physicians regularly.