Esophageal cancer is a cancerous or malignant tumor of the esophagus or the food pipe that allows food to move from the mouth to the stomach.
It is a common cancer especially among men over 50 years old. (1)
What is the esophagus?
The esophagus is a 10 inch long muscular tube that lies in the chest. It connects the back of the mouth to the stomach.
The pharynx lies at its upper end and at the lower end between the esophagus and stomach lies a gate called the lower esophageal sphincter.
The walls of the esophagus have several layers. The inner lining is the mucosa which is moist and slimy to allow passage of food.
Underneath it lays the Submucosa. It contains the glands that secrete mucus to keep the mucosa moist.
Beneath this is the muscle layer that pushes and propels the food forward. There is also an outer layer covering the esophagus. (1, 2)
Types of esophageal cancer
There are two basic types of esophageal cancer. These differ in their microscopic features. (1-5)
Squamous cell carcinoma
This type of cancer is related to excessive smoking and alcohol consumption. It is common in the upper and middle part of the esophagus.
Worldwide it is the most common type of esophageal cancer. Among Americans, however, the number is declining.
Squamous cell carcinoma is responsible for 95% of all esophageal cancers worldwide.
This type of cancer is common among obese men and among those who smoke excessively.
This is the most common type of esophageal cancer among Americans. It commonly begins in the glands of the lower part of the esophagus.
A condition called Barrett’s esophagus results from long term irritation of the lower part of the esophagus due to acid reflux from the stomach. This raises the risk of adenocarcinoma.
The exact cause of this cancer is unknown but some risk factors have been identified. These mainly are things that continuously irritate the esophagus. This could be by smoking or alcohol consumption or by acid regurgitation from the stomach.
Who is at risk of esophageal cancer?
African-Americans have a higher risk of esophageal cancer than whites in the United States.
Esophageal cancer is more common in men than in women. The male-to-female ratio is 3-4:1.
The disease becomes more common with advancing age. It is about 20 times more common in those older than 65 years than in persons younger than 65 years. (5)
The cancer usually begins in cells in the inner layer of the esophagus. With time the cancer invades deeper into the layers of the esophagus and nearby tissues.
The cancer cells may also break free from the tumor and enter blood vessels or lymph vessels. This carries the cancer to distant organs like the liver etc. This is called metastasis of the cancer.
Esophageal cancer is the seventh most common cause of cancer death among men.
In the United States it is estimated that this year will see 17,460 adults (13,950 men and 3,510 women) developing and being diagnosed with this cancer.
Further estimates show that there will be 15,070 deaths (12,040 men and 3,030 women) from this disease this year.
Rates of survival for at least five years after the cancer is diagnosed with this cancer is very low at 17%. These numbers come from American Cancer Society's publication, Cancer Facts & Figures 2012.
Incidence of esophageal carcinoma can be as high as 30-800 cases per 100,000 persons in particular areas of northern Iran, southern Russia, and northern China. (4-6)