In 2011, it is estimated that 21,520 Americans will be diagnosed with gastric cancer and 10,340 will die of it. Two-thirds of people diagnosed with gastric cancer are older than 66 years. The disease is much more common in other countries, principally Japan, Central Europe, Scandinavia, Hong Kong, South and Central America, the Soviet Union, China, and Korea. Gastric cancer is a major cause of death worldwide, especially in developing countries. The major type of gastric cancer is adenocarcinoma (90%). The remaining 10% include lymphomas, sarcomas, and other rare types. Gastric adenocarcinomas can be further categorized into an intestinal type and a diffuse type. Intestinal-type lesions are frequently ulcerative and occur in the distal stomach more often than the diffuse type. Diffuse-type lesions are associated with a worse prognosis than the intestinal type. The intestinal type tends to predominate in geographic regions with a high incidence of gastric carcinoma. The decline in the incidence of gastric cancer worldwide is largely due to a decrease in the number of intestinal-type lesions.
The incidence of gastric cancer in the United States has decreased fourfold since 1930 to approximately seven cases per 100,000 people. The reasons for this striking decrease in incidence are unknown but are suspected to be related to improved storage of food or changes in diet such as decreased salt intake. Risk factors for gastric cancer include the presence of precursor conditions such as chronic atrophic gastritis and intestinal metaplasia, pernicious anemia, and gastric adenomatous polyps. Genetic and environmental factors include a family history of gastric cancer; low consumption of fruits and vegetables; consumption of salted, smoked, or poorly preserved foods; and cigarette smoking. There is increasing evidence that Helicobacter pylori infection of the stomach is associated with both the initiation and promotion of gastric carcinoma and gastric lymphoma.[6,7,8] Compared with the general population, people with duodenal ulcer disease may have a lower risk of gastric cancer. There is considerable dispute as to whether partial gastrectomy, especially Billroth II gastrectomy for benign causes, increases risk.[10,11]
American Cancer Society.: Cancer Facts and Figures 2011. Atlanta, Ga: American Cancer Society, 2011. Also available online. Last accessed July 27, 2011.
American Cancer Society.: Cancer Facts and Figures 2005. Atlanta, Ga: American Cancer Society, 2005. . Also available online. Last accessed July 15, 2011.
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