Definition: Stomach & Esophageal Cancers
Stomach cancer, also known as gastric cancer, is cancer that starts in any part of the stomach. The American Cancer Society estimates that 21,000 Americans will be newly diagnosed with stomach cancer during 2010. The risk of a person developing stomach cancer in their lifetime is about 1 in 112, but it is slightly higher in men than in women. Almost two thirds of people with this disease are older than 65.
Esophageal cancer is a cancer that develops in the esophagus, the muscular tube that connects the throat to the stomach. The esophagus, located just behind the trachea, allows food to enter the stomach for digestion. The wall of the esophagus is made up of several layers, and cancers generally start from the inner layer and grow out. This disease is three to four times more common among men than among women. The American Cancer Society estimates that over 16,000 Americans are newly diagnosed with esophageal cancer each year.
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After food is chewed and swallowed, it enters the esophagus, a tube that carries food through the neck and chest to the stomach. The esophagus joins the stomach at the gastroesophageal junction, which is located just beneath the diaphragm (the breathing muscle under the lungs). The stomach is a sac-like organ that holds food and starts to digest it by secreting gastric juice. The food and gastric juice are mixed and then emptied into the first part of the small intestine called the duodenum.
Some people use the word stomach to refer to the area of the body between the chest and the pelvic area. The medical term for this area is the abdomen. For instance, some people with pain in this area would say they have a “stomach ache,” when in fact the pain could be coming from the appendix, small intestine, colon (large intestine), or other organs in the area. Doctors would refer to this symptom as abdominal pain, because the stomach is only one of many organs in the abdomen in which cancers may start. Stomach cancer should not be confused with cancers of the colon, liver, pancreas, or small intestine.
Cancers starting in different sections of the stomach may cause different symptoms and tend to have different outcomes. The location can also affect treatment options. Cancers that start at the gastroesophageal junction are grouped with cancers of the esophagus for the purposes of staging and treatment. A cancer that started in the cardia of the stomach but then grew into the gastroesophageal junction is also staged and treated like a cancer of the esophagus.
What Are The Different Types of Stomach Cancer?
About 90 to 95 percent of cancerous (malignant) tumors of the stomach are adenocarcinomas. The term stomach cancer, or gastric cancer, almost always refers to adenocarcinoma. This cancer develops from the cells that form the innermost lining of the stomach (known as the mucosa).
The other types of cancer that can be found in the stomach include lymphomas, gastrointestinal stromal tumors, and carcinoid tumors. Lymphomas are cancers of the immune system tissue that are sometimes found in the wall of the stomach. They account for about 4 percent of stomach cancers. Gastrointestinal stromal tumors are rare tumors that seem to start in cells in the wall of the stomach called interstitial cells of Cajal. Some are non-cancerous (benign); others are cancerous. Although these tumors can be found anywhere in the digestive tract, about 60 to 70 percent occur in the stomach. Carcinoid tumors start in hormone-making cells of the stomach. Most of these tumors do not spread to other organs. About 3 percent of stomach cancers are carcinoid tumors.
Although the exact cause of stomach cancer is not known, the following are thought to be risk factors for stomach cancer:
- Helicobacter pylori infection
- Diet that includes the following: large amounts of smoked food; salted fish and meat; high-starch, low-fiber foods; pickled vegetables; foods and beverages that contain nitrates and nitrites
- Tobacco use
- Alcohol abuse
- Previous stomach surgery
- Megaloblastic (pernicious) anemia (caused by vitamin B12 deficiency)
- Menetrier’s disease
- Age 50 or older—almost two thirds of people with stomach cancer are older than 65, and the average age at the time of diagnosis is 71
- Men are at greater risk than women
- Having blood type A
- Family history of the following: nonpolyposis colon cancer; familial adenomatous polyposis; stomach cancer
- History of stomach polyps
- Exposure to environmental factors such as dusts and fumes in the workplace
- Asians, Pacific Islanders, Hispanics, and African Americans are at greater risk
The esophagus, located just behind the trachea, is about 10 to 13 inches in length and allows food to enter the stomach for digestion. At the top of the esophagus is a muscle, called the sphincter, that releases to let food or liquid go through. The lower part of the esophagus is connected to the stomach. Another muscle is located at this connection that opens to allow the food to enter the stomach. This muscle also works to keep food and juices from the stomach from backing into the esophagus. When these juices do back up, reflux, commonly known as heartburn, occurs.
Long-term reflux can change the cells in the lower end of the esophagus. This condition is known as Barrett’s esophagus. If these cells are not treated, they are at much higher risk of developing into cancer cells.
What Are The Different Types of Esophageal Cancer?
There are two main types of esophageal cancer. The most common type of esophageal cancer, known as adenocarcinoma, develops in the glandular tissue in the lower part of the esophagus, near the opening of the stomach. It occurs in just over 50 percent of cases.
Squamous cell carcinoma grows in the cells that form the top layer of the lining of the esophagus, known as squamous cells. This type of cancer can grow anywhere along the esophagus.
Treatment for both types of esophageal cancer is similar.
Although the exact cause of esophageal cancer is not known, the following factors can put an individual at greater risk:
- Age 65 or older
- Men have a three times greater risk than women
- Tobacco use
- Alcohol use—Chronic or long-term heavy drinking, more than three alcoholic drinks per day
- Barrett’s esophagus
- Diets low in fruits and vegetables and certain vitamins and minerals
- Swallowing caustic irritants such as lye and other substances can burn and destroy cells in the esophagus. The scarring and damage done to the esophagus can put a person at greater risk for developing cancer many years after ingesting the substance.
- History pf achalasia, a disease in which the bottom of the esophagus does not open to release food into the stomach
- History of tylosis, a rare, inherited disease
- History of other head and neck cancers
- Acid reflux