The stomach is a J-shaped organ in the upper abdomen. It is part of the digestive system, which processes nutrients (vitamins, minerals, carbohydrates, fats, proteins, and water) in foods that are eaten and helps pass waste material out of the body. Food moves from the throat to the stomach through a hollow, muscular tube called the esophagus. After leaving the stomach, partly-digested food passes into the small intestine and then into the large intestine (the colon).
The wall of the stomach is made up of 3 layers of tissue: the mucosal (innermost) layer, the muscularis (middle) layer, and the serosal (outermost) layer. Gastric cancer begins in the cells lining the mucosal layer and spreads through the outer layers as it grows.
Stromal tumors of the stomach begin in supporting connective tissue and are treated differently from gastric cancer. Refer to the PDQ summary on Adult Soft Tissue Sarcoma Treatment for more information.
Age, diet, and stomach disease can affect the risk of developing gastric cancer.
Risk factors include the following:
- Helicobacter pylori infection of the stomach.
- Chronic gastritis (inflammation of the stomach).
- Older age.
- Being male.
- A diet high in salted, smoked, or poorly preserved foods and low in fruits and vegetables.
- Pernicious anemia.
- Smoking cigarettes.
- Intestinal metaplasia.
- Familial adenomatous polyposis (FAP) or gastric polyps.
- A mother, father, sister, or brother who has had stomach cancer.
More information on stomach cancer