Your esophagus is a 10-inch long, hollow, muscular tube that connects your throat to your stomach. The wall of the esophagus has several layers of tissue that work together to push food down into your stomach when you swallow.
Esophageal cancer typically starts in the cells that line the esophagus. From there it may spread into the esophageal wall and to nearby lymph nodes or other tissues or organs.
What is Esophageal Cancer?
Esophageal cancer occurs when cells in the esophagus begin to grow abnormally. They do not respond to regular cell growth, division, and death signals like they are supposed to. They also don’t organize normally. Instead they grow into a tumor, which may extend into the open space inside your esophagus or break through underlying layers of your esophageal wall.
Several layers of tissue make up the wall of your esophagus.
- Thin, flat squamous cells line the inside of most of your esophagus. Closer to your stomach, the lining of the esophagus is made up of glandular epithelial cells.
- Under the lining of the esophagus are submucosal tissues, which keep your esophagus moist.
- Thick muscles under the submucosal tissues contract in waves to push food down your esophagus.
- Connective tissue forms the outer covering of your esophagus.
Types of Esophageal Cancer
Usually esophageal cancer starts in the glandular epithelial cells or squamous cells that line the esophagus.
- Cancer that starts in the glandular epithelial cells is called adenocarcinoma. Adenocarcinoma tumors usually grow near the bottom of the esophagus, where the esophagus meets the stomach. Often these tumors arise in people with Barrett’s esophagus.
- Cancer that starts in the squamous cells is called squamous cell carcinoma. Squamous cell carcinoma can grow anywhere in the esophagus, but it occurs most often in the upper and middle esophagus.
In the U.S., adenocarcinoma is more common than squamous cell carcinoma. The reverse is true in the rest of the world. As the use of cigarettes and tobacco has dropped in the U.S., the incidence of squamous cell cancer has dropped as well. As the rates of gastroesophageal reflux disease and obesity have risen in the last two decades, so has the rate of adenocarcinoma. Read more about these and other risk factors for esophageal cancer.
Cells from esophageal cancer can spread outside your esophagus either by breaking through the wall of the esophagus or by entering your bloodstream or lymph system and traveling elsewhere in your body.