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 wall of the stomach is made up of 5 layers of tissue. From the innermost layer to the outermost layer, the layers of the stomach wall are: mucosa, submucosa, muscle, subserosa (connective tissue), and serosa. Gastric cancer begins in the mucosa 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. See the PDQ summary on Gastrointestinal Stromal Tumors Treatment (Adult) for more information.

Age, diet, and stomach disease can affect the risk of developing gastric cancer.

Anything that increases your risk of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn't mean that you will not get cancer. Talk with your doctor if you think you may be at risk. Risk factors for gastric cancer include the following:

 

Having any of the following medical conditions:

Helicobacter pylori (H. pylori) infection of the stomach.

Chronic gastritis (inflammation of the stomach).

Pernicious anemia.

Intestinal metaplasia (a condition in which the normal stomach lining is replaced with the cells that line the intestines).

Gastric polyps.

Epstein-Barr virus infection.

Familial syndromes (including familial adenomatous polyposis).

Eating a diet high in salted, smoked foods and low in fruits and vegetables.

Eating foods that have not been prepared or stored properly.

Being older or male.

Smoking cigarettes.

Having a mother, father, sister, or brother who has had stomach cancer.

Symptoms of gastric cancer include indigestion and stomach discomfort or pain.

These and other signs and symptoms may be caused by gastric cancer or by other conditions.

 

In the early stages of gastric cancer, the following symptoms may occur:

 

Indigestion and stomach discomfort.

A bloated feeling after eating.

Mild nausea.

Loss of appetite.

Heartburn.

In more advanced stages of gastric cancer, the following signs and symptoms may occur:

 

Blood in the stool.

Vomiting.

Weight loss for no known reason.

Stomach pain.

Jaundice (yellowing of eyes and skin).

Ascites (build-up of fluid in the abdomen).

Trouble swallowing.

Check with your doctor if you have any of these problems.

 

Tests that examine the stomach and esophagus are used to diagnose gastric cancer.

The following tests and procedures may be used:

 

Physical exam and health history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient’s health habits and past illnesses and treatments will also be taken.

Blood chemistry studies: A procedure in which a blood sample is checked to measure the amounts of certain substances released into the blood by organs and tissues in the body. An unusual (higher or lower than normal) amount of a substance can be a sign of disease.

Complete blood count (CBC): A procedure in which a sample of blood is drawn and checked for the following:

The number of red blood cells, white blood cells, and platelets.

The amount of hemoglobin (the protein that carries oxygen) in the red blood cells.

The portion of the sample made up of red blood cells.

Upper endoscopy: A procedure to look inside the esophagus, stomach, and duodenum (first part of the small intestine) to check for abnormal areas. An endoscope (a thin, lighted tube) is passed through the mouth and down the throat into the esophagus.