Cancer is a disease in which cells grow in an abnormal way. Normally, the cells divide in a controlled manner. If cells keep dividing when new cells are not needed, a mass of tissue called a tumor forms.
A tumor can be benign or malignant. A benign tumor is not cancer and will not spread to other parts of the body. A malignant tumor is cancer. Cancer cells invade and damage tissue around them. They can also enter the lymph and blood streams, spreading to other parts of the body. Esophageal cancer is the development of malignant cells in the esophagus.
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.
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. Merck Manual Professional Version website. Available at: ...(Click grey area to select URL) Updated October 2017. Accessed December 31, 2018.
Esophagus cancer. American Cancer Society website. Available at ...(Click grey area to select URL) Accessed December 31, 2018.
General information about esophageal cancer. National Cancer Institute website. Available at:
https://www.cancer.gov/types/esophageal/patient/esophageal-treatment-pdq#section/all. Updated September 7, 2018. Accessed December 31, 2018.