Cancer is when cells in the body change and grow out of control. Your body is made up of tiny building blocks called cells. Normal cells grow when your body needs them, and die when your body doesn't need them any longer.

Cancer is made up of abnormal cells that grow even though your body doesn't need them. In most cancers, the abnormal cells grow to form a lump or mass called a tumor. If cancer cells are in the body long enough, they can grow into (invade) nearby areas. They can even spread to other parts of the body (metastasis).

Esophageal cancer is cancer that starts in your esophagus.

The esophagus is a tube that makes up part of the digestive tract. It carries the food and liquid you eat from your throat to your stomach. In adults, it’s about 10 inches long. The esophagus is located behind the windpipe (trachea) and in front of your spine.

When you swallow, the esophagus tightens and relaxes. This causes “waves” along the tube. This motion moves food down into your stomach. Glands in the esophagus create mucus to keep the lining moist and make swallowing easier.

The wall of the esophagus has several layers. The innermost lining is called the mucosa. This is made up mainly of flat cells called squamous cells. If stomach acid enters the lower part of the esophagus (acid reflux) over a long period of time, the squamous cells can be replaced by glandular cells. Then mucus and other fluids are made to try to protect the lower part of the esophagus. This is called Barrett's esophagus.

The lower end of the esophagus connects to the stomach at the gastroesophageal junction (GEJ).

There are 2 main types of esophageal cancer:

• Adenocarcinoma. These are cancers that start in glandular cells. In the U.S. and other Western countries, most esophageal cancers are adenocarcinomas. These cancers normally start in the lower part of the esophagus where gland cells have replaced squamous cells.This is what happens in Barrett's esophagus.

• Squamous cell carcinoma. These cancers start in squamous cells. This type of cancer can start anywhere along the esophagus.

There are other types of esophageal cancer, but they are rare.

Adenocarcinoma of the esophagus often starts in people with Barrett's esophagus. Still, most people with Barrett's esophagus never get esophageal cancer.

Over time, the gland cells that replace the squamous cells can develop dysplasia. This is when glandular cells start to look abnormal and grow in an abnormal way. Esophageal dysplasia is a pre-cancerous condition.

Both types of esophageal cancer start in the inner lining of the esophagus. As these cancers grow, they often narrow the opening in the middle of the esophagus. This is called the lumen. This can cause problems with swallowing.

The cancer can also grow outward, through the layers of the esophagus to nearby tissues. These include nearby lymph nodes and the windpipe. Once the cancer has grown outside the esophagus, it can also spread to other parts of your body. It may spread to other organs, such as your stomach, liver, or lungs.

If you have questions about esophageal cancer, talk with your healthcare provider. He or she can help you understand more about this cancer.