The esophagus is the portion of the digestive system that leads from the mouth to the stomach. Sometimes called the gullet, it is a muscular passageway that begins at the throat, or pharynx. Located between the trachea and the spine, it passes down through the diaphragm and ends at the lower esophageal sphincter, a muscular ring opening into the upper end of the stomach.
The primary function of the esophagus is to carry ingested food and liquids to the stomach. When a person eats or drinks and swallows, the sphincter at the top of the structure, which is normally closed, opens and allows the material to pass through. The muscles in the walls of the passage then contract, pushing it downward; this process is facilitated by the mucus produced by glands along the esophagus to keep it moist. It then passes through the lower sphincter, which also relaxes and opens, and enters into the stomach.
Sometimes the lower esophageal sphincter opens at times other than when food is being swallowed, and allows acid from the stomach to splash up into the esophagus. This is known as acid reflux and typically causes heartburn, a burning sensation in the lower chest that is uncomfortable but not dangerous. When acid reflux becomes chronic, it is called gastroesophageal reflux disease, or GERD. GERD is a fairly common disorder and should be treated, as over time it can cause damage. Treatment typically includes medications such as antacids, H2 blockers, and proton pump inhibitors.
People with GERD may develop a condition called Barrett’s esophagus. In these cases, cells in the lower esophagus change and are replaced with cells like those in the stomach and intestines. These cells are tolerant of the acid from the stomach, which helps them resist the damage from the reflux. While this may reduce the person’s discomfort from heartburn, the condition is a cause for concern, as the Barrett’s cells can sometimes lead to a form of cancer known as adenocarcinoma.
In addition to adenocarcinoma, the other main type of esophageal cancer is squamous cell carcinoma. This type of cancer is often associated with use of tobacco or alcohol, though it can have other causes. Both types of cancer usually cause pain and difficulty swallowing, which may lead to weight loss in patients. Treatments can include endoscopic therapy to remove localized lesions or laser therapy and chemotherapy to destroy tumor cells.