Wednesday, August 29, 2007

Stomach Cancer


Stomach cancer (also called gastric cancer) can develop in any part of the stomach and may spread throughout the stomach and to other organs; particularly the esophagus and the small intestine. Stomach cancer causes nearly one million deaths worldwide per year.[1]

Stomach cancer represents roughly 2% (25,500) cases of all new cancer cases yearly in the United States, but it is much more common in Korea, Japan, Great Britain, South America, and Iceland. It is associated with high salt in the diet, smoking, and low intake of fruits and vegetables. Infection with H. pylori is the main risk factor in about 80% or more of gastric cancers. It is more common in men.

Gastric or stomach cancer has very high incidence in Korea and Japan. Gastric cancer is the leading cancer type in Korea with 20.8% of malignant neoplasms, the second leading cause of cancer deaths. It is suspected several risk factors are involved including diet, gastritis, intestinal metaplasia and Helicobacter pylori infection. A Korean diet, high in salted, stewed and broiled foods, is thought to be a contributing factor. Ten percent of cases show a genetic component.[2]

In Japan and other countries bracken consumption and spores are correlated to stomach cancer incidence.[3] Epidemiologists have yet to fully account for the high rates of gastric cancer as compared to other countries.

A very small percentage of diffuse-type gastric cancers (see Histopathology below) are thought to be genetic. Hereditary Diffuse Gastric Cancer (HDGC) has recently been identified and research is ongoing. However, genetic testing and treatment options are already available for families at risk (Brooks-Wilson et al., 2004).

Metastasis occurs in 80-90% of individuals with stomach cancer, with a five year survival rate of 75% in those diagnosed in early stages and less than 30% of those diagnosed in late stages. The death rate is 12,400 a year in the United States.


Stomach cancer is often asymptomatic or causes only nonspecific symptoms in its early stages. By the time symptoms occur, the cancer has generally metastasized to other parts of the body, one of the main reasons for its poor prognosis. Stomach cancer can cause the following signs and symptoms:
Indigestion or a burning sensation (heartburn)
Loss of appetite, especially for meat

Abdominal pain or discomfort in the upper abdomen
Nausea and vomiting
Diarrhea or constipation
Bloating of the stomach after meals
Weight loss
Weakness and fatigue
Bleeding (vomiting blood or having blood in the stool), which can lead to anemia

These can be symptoms of other health problems, such as a stomach virus or gastric ulcer, and diagnosis should be done by a gastroenterologist or an oncologist.


Risk factors

No one knows the exact causes of stomach cancer. Doctors often cannot explain why one person develops this disease and another does not.

Research has shown that people with certain risk factors are more likely than others to develop stomach cancer. A risk factor is something that may increase the chance of developing a disease.
Studies have found the following risk factors for stomach cancer:

Age: Most people with this disease are 72 or older.
Sex: Men are more likely than women to develop stomach cancer.
Race: Stomach cancer is more common in Asian, Pacific Islander, Hispanic, and African Americans than in non-Hispanic white Americans.

Diet: Studies suggest that people who eat a diet high in foods that are smoked, salted, or pickled may be at increased risk for stomach cancer. On the other hand, eating fresh fruits and vegetables may protect against this disease.

Helicobacter pylori infection: H. pylori is a type of bacteria that commonly lives in the stomach.

H. pylori infection increases the risk of stomach inflammation and stomach ulcers. It also increases the risk of stomach cancer, but only a small number of infected people develop stomach cancer. Although infection increases the risk, cancer is not contagious. You cannot catch stomach cancer from another person who has it.

Smoking: People who smoke are more likely to develop stomach cancer than people who do not smoke.

Certain health problems: Conditions that cause inflammation or other problems in the stomach may increase the risk of stomach cancer:

Stomach surgery

Chronic gastritis (long-term inflammation of the stomach lining)

Pernicious anemia (a blood disease that affects the stomach)

Family history: A rare type of stomach cancer runs in some families.
Most people who have known risk factors do not develop stomach cancer. For example, many people have H. pylori in their stomach but never develop cancer. On the other hand, people who do develop the disease sometimes have no known risk factors.

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