Normal Anatomy and the Development of Esophageal Cancer

The esophagus is a muscular tube. It is about 12 inches long and connects the throat to the stomach. Chewed food is formed into a small mass called a bolus in the mouth. Once the bolus is swallowed, the esophagus moves it down into the stomach. It uses rhythmic squeezing of the muscles.

The esophagus has 2 muscular rings called the upper and lower sphincters. The upper sphincter is controlled by swallowing. It allows food to move into the esophagus. The lower sphincter (LES) allow food to pass into the stomach. Once food passes through, the LES closes to help keep food and stomach acids in during digestion.

The inside lining of the esophagus is an active area. There can be a lot of cell damage which increases the need for new cell growth. Stomach acid, alcohol, tobacco, and certain foods can add to cell turnover need. Chronic conditions, such as gastroesophageal reflux disease (GERD), also cause damage and turnover. Higher rates of turnover increase the chance of a cancer developing.

Tumors can cause blockages in the esophagus. This can make it hard to swallow food. The tumor can also grow beyond the esophagus. It can spread to nearby spine, airway, or major artery. The cancer can cause damage to these structures as well. It can also spread to lymph nodes or blood vessels. There, the cancer can spread to other areas of the body. The most common sites for esophageal cancer to spread to are the lungs, liver, kidney, and bones.

Types of Esophageal Cancer

There are 2 main types of esophageal cancer that make up nearly all esophageal cancers found:

• Squamous cell carcinoma —start from the innermost lining of the esophagus.
• Adenocarcinoma —start from cells closest to the stomach. Associated with acid exposure in the esophagus from GERD. Barrett's esophagus is a change in esophageal cells which has a high risk of progressing into adenocarcinoma.

Esophageal Cancer

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