Overview of Esophageal Cancer
The esophagus is the hollow, muscular tube that carries food and liquids from the throat to the stomach. It is part of the digestive system and is located between the windpipe (trachea) and the spine. In adults, the esophagus is about 10 inches long. Esophageal cancer usually originates in the lining of the esophagus (called the mucosa) and can develop in the upper, middle, or lower section of the organ.
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The most common types of esophageal cancer are squamous cell carcinoma and adenocarcinoma. Squamous cell carcinoma develops in flat cells that line the esophagus. Approximately 60% of squamous cell carcinomas develop in the middle third of the organ, 30% occur in the lower third, and 10% occur in the upper third.
Adenocarcinoma develops in the lining of the esophagus and is associated with a condition called Barrett's esophagus. This type usually occurs in the lower third of the esophagus.
Incidence and Prevalence of Esophageal Cancer
According to the National Cancer Institute (NCI), esophageal cancer is the third most common cancer of the digestive tract and the seventh leading cause of cancer-related deaths worldwide. Overall incidence of the disease is highest in men over the age of 50.
Incidence of esophageal cancer varies considerably according to geographic location. It is more common in northern China, northern Iran, and southern republics of the former Soviet Union, and is less common in Japan, Great Britain, Europe and Canada. In the United States, incidence is highest in urban areas and overall incidence is about 5 in 100,000.
Squamous cell carcinoma of the esophagus accounts for most cases worldwide and about 40% of cases in the United States. This type is more common in African American men and is associated with cigarette smoking and high intake of alcohol.
According to the NCI, incidence of adenocarcinoma of the esophagus, which is associated with Barrett's esophagus, is rising in the United States. This type is more common in Caucasian men over the age of 60.