The esophagus is the tube through which food and drink pass from the back of the throat to the stomach. It lies in the back of the chest just in front of the spine.
The outer muscular layers of the esophagus move fluid or food toward the stomach. At the lower end there is a muscular valve that prevents stomach acid from entering the esophagus from below.
What is esophageal cancer?
The cancer arises from the lining of the esophagus, narrowing the esophagus and causing difficulty in swallowing. First, solid food tends to lodge or stick and then liquids. The cancerous cells may also spread outside the esophagus to involve the neighboring structures, such as lymph nodes and blood vessels in the chest, and they may be carried in the blood stream to form secondary tumor in the liver or elsewhere.
Most cancers in the upper two-thirds of the esophagus are known as squamous carcinomas from the squamous (skin-like) cells that line the esophagus. Those occurring near the link with the stomach are usually adenocarcinomas, derived from stomach-like cells. This is particularly the case when stomach-type (columnar) cells have replaced squamous cells at the lower end of the esophagus, a condition known as Barrett’s esophagus.