Gastric or stomach cancer is an uncommon type of cancer in the United States. According to the American Cancer Society, approximately 21,130 new cases of stomach cancer were diagnosed in the United States in 2009, accounting for roughly 1.4 percent of all newly diagnosed cancers. Several known factors contribute to the development of stomach cancer. Awareness of gastric cancer causes can help guide actions to alter modifiable risk.
Helicobacter Pylori Infection
The National Cancer Institute reports that infection with the bacterium Helicobacter pylori is the most important contributing factor to the development of gastric cancer. H. pylori commonly infects the stomach. According to the National Institute of Diabetes and Digestive and Kidney Diseases, approximately 20 percent of Americans younger than age 40, and 50 percent of those older than age 60, have H. pylori in the stomach. While most people with H. pylori infection do not develop stomach cancer, some do. H. pylori infection is most strongly linked to gastric cancers in the lower part of the stomach, known as non-cardia gastric cancers.
Smoking
Smoking is a significant contributing factor to the development of stomach cancer. The American Cancer Society reports that current male smokers have double the risk of stomach cancer compared to nonsmoking men. Among female smokers, the risk of gastric cancer is one and a half times greater compared to nonsmoking women. More than one-quarter of stomach cancer deaths in American men and 12 percent of those in women are caused by smoking, notes the American Cancer Society.
Diet
Dietary habits have a role in the development of gastric cancer. According to the Mayo Clinic, diets high in smoked, pickled and salty foods, and consumption of foods contaminated with aflatoxins, increase the risk for stomach cancer. Aflatoxins are noxious chemicals produced by molds that may live on corn, wheat, cottonseed, peanuts and nuts from trees. Diets low in fresh vegetables and fruits can also contribute to stomach cancer development.
Stomach Disorders
The American Cancer Society notes that several stomach disorders may contribute to the development of gastric cancer. Hypertrophic gastropathy, Lynch syndrome, pernicious anemia, familial adenomatous polyposis, adenomatous polyps and stomach lymphoma are associated with an increased risk for stomach cancer.
Genetics
Genetic makeup can contribute to the development of stomach cancer. People with type A blood and those with the abnormal breast cancer genes BRCA1 and BRCA2 have an increased risk for gastric cancer. Although there is no single gene that directly causes gastric cancer, the American Cancer Society notes that people with a first-degree relative who developed gastric cancer have an increased risk of also developing stomach cancer.
References
- American Cancer Society: What Are the Risk Factors for Stomach Cancer?
- National Cancer Institute: What You Need to Know About Stomach Cancer, Risk Factors
- National Cancer Institute: Stomach (Gastric) Cancer Prevention, Summary of Evidence
- National Cancer Institute: H. pylori and Cancer, Fact Sheet
- Mayo Clinic: Stomach Cancer, Risk Factors
