What Is Cancer of the Esophagus?

Cancer starts when cells in the body begin to grow out of control. Cells in nearly any part of the body can become cancer, and can spread to other areas of the body. To learn more about how cancers start and spread, see What Is Cancer?

How the esophagus works

To understand esophagus cancer, it helps to know about the normal structure and function of the esophagus.

The esophagus is a hollow, muscular tube that connects the throat to the stomach. It lies behind the trachea (windpipe) and in front of the spine.

Food and liquids that are swallowed travel through the inside of the esophagus (called the lumen) to reach the stomach. In adults, the esophagus is usually between 10 and 13 inches (25 to 33 centimeters [cm]) long and is about ¾ of an inch (2cm) across at its smallest point.

The upper part of the esophagus has a special ring of muscle at its beginning that relaxes to open the esophagus when it senses food or liquid coming toward it. This muscle is called the upper esophageal sphincter.

The lower part of the esophagus that connects to the stomach is called the gastroesophageal (GE) junction. A special ring of muscle near the GE junction, called the lower esophageal sphincter, controls the movement of food from the esophagus into the stomach. Between meals, it closes to keep the stomach’s acid and digestive juices out of the esophagus.

illustration of the digestive system showing the liver, gallbladder, ascending colon, small intestine, cecum, appendix, rectum, esophagus, stomach, transverse colon, descending colon, sigmoid colon and anus

The wall of the esophagus has several layers. These layers are important for understanding where cancers in the esophagus usually start and how they can grow.

illustration showing the location of the esophagus in the body as well as a detailed cross section showing the layers of the esophagus including the mucosa (epithelium, lamina propria, muscularis mucosa), submucosa, muscularis propria and adventitia

Mucosa: This layer lines the inside of the esophagus. The mucosa has 3 parts:

  • The epithelium is the innermost lining of the esophagus and is normally made up of flat, thin cells called squamous cells. This is where most cancers of the esophagus start.
  • The lamina propria is a thin layer of connective tissue right under the epithelium.
  • The muscularis mucosa is a very thin layer of muscle under the lamina propria.

Submucosa: This is a layer of connective tissue just below the mucosa that contains blood vessels and nerves. In some parts of the esophagus, this layer also includes glands that secrete mucus.

Muscularis propria: This is a thick layer of muscle under the submucosa. It contracts in a coordinated way to push food down the esophagus from the throat to the stomach.

Adventitia: This is the outermost layer of the esophagus, and is formed by connective tissue.

Esophageal cancer

Cancer of the esophagus (also called esophageal cancer) starts in the inner layer (the mucosa) and grows outward (through the submucosa and the muscle layer). Since 2 types of cells can line the esophagus, there are 2 main types of esophageal cancer:

Squamous cell carcinoma

The esophagus is normally lined with squamous cells. Cancer starting in these cells is called squamous cell carcinoma. This type of cancer can occur anywhere along the esophagus, but is most common in the portion of the esophagus located in the neck region and in the upper two-thirds of the chest cavity.  Squamous cell carcinoma used to be the most common type of esophageal cancer in the United States. This has changed over time, and now it makes up less than half of esophageal cancers in this country.

Adenocarcinoma

Cancers that start in gland cells  (cells that make mucus) are called adenocarcinomas. This type of cancer usually occurs in the distal (lower third) part of the esophagus. Before an adenocarcinoma can develop, gland cells must replace an area of squamous cells, which is what happens in Barrett’s esophagus. This occurs mainly in the lower esophagus, which is where most adenocarcinomas start.

Adenocarcinomas that start at the area where the esophagus joins the stomach (the GE junction, which includes about the first 2 inches (5 cm) of the stomach called the cardia), tend to behave like cancers in the esophagus (and are treated like them, as well), so they are grouped with esophagus cancers.

Rare cancers

Other types of cancer can also start in the esophagus, including lymphomas, melanomas, and sarcomas. But these cancers are rare and are not discussed further here.

The American Cancer Society medical and editorial content team
Our team is made up of doctors and master’s-prepared nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

American Cancer Society. Cancer Facts & Figures 2017. Atlanta, Ga: American Cancer Society; 2017.

Kleinberg L, Kelly R, Yang S, Wang JS, Forastiere AA. Chapter 74 – Cancer of the Esophagus. In: Niederhuber JE, Armitage JO, Dorshow JH, Kastan MB, Tepper JE, eds. Abeloff’s Clinical Oncology. 5th ed. Philadelphia, Pa. Elsevier: 2014.

Posner MC, Minsky B, Ilson DH. Chapter 45: Cancer of the esophagus. In: DeVita VT, Hellman S, Rosenberg SA, eds. DeVita, Hellman, and Rosenberg’s Cancer: Principles and Practice of Oncology. 10th ed. Philadelphia, Pa: Lippincott-Williams & Wilkins; 2015.

Last Medical Review: June 14, 2017 Last Revised: June 14, 2017

 

 

 

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