Stomach cancer epidemiology and demographics

Epidemiology
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 the bacterium 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. In Japan and other countries bracken consumption and spores are correlated to stomach cancer incidence. 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.