Basic information of stomach cancer

by Specialist

Gastric cancer is a disease in which malignant tumor (cancer) cells form in the gastric mucosa.

The stomach is a J-shaped organ located in the upper abdomen of the body. It is part of the digestive system. The digestive system primarily processes the nutrients (vitamins, minerals, carbohydrates, fats, proteins, and water) in the food the body consumes and helps get waste products out of the body. To pass from the pharynx into the stomach, food passes through an intermediate hollow tube made of muscle called the esophagus. After leaving the stomach, the partially digested food enters the small intestine and then the large intestine.

The esophagus and stomach are part of the upper GI (digestive) system.

The stomach wall is composed of five layers of tissue. From the innermost to the outermost layer, they are, in order: the mucosal layer, the submucosal layer, the muscular layer, the subplasmalemma (connective tissue), and the plasma layer. Gastric cancer originates in the mucosal layer and gradually spreads to the outer layers as it grows.

Gastric mesenchymal tumors originate in the supporting connective tissue of the stomach lining and are treated differently than gastric cancer. For more information, see the PDQ summary on the treatment of gastrointestinal mesenchymal tumors (adults).

For more information about gastric cancer, read the PDQ summary below.

  • About treatments for rare cancers in children
  • Gastric cancer prevention
  • Stomach cancer screening

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

    Any factor that increases the chance of developing the disease is called a risk factor. Having a risk factor does not mean you will get cancer, and not having a risk factor does not mean you will not get cancer. If you feel such a risk, then consult with your doctor early. Risk factors for stomach cancer include the following:

  • Having any of the following signs of disease.
  • H. pylori infection in the stomach.
  • Chronic gastritis (inflammation of the stomach).
  • Pernicious anemia.
  • Intestinal epithelial metaplasia (a disease in which normal gastric mucosal cells are replaced by small intestinal epithelial cells).
  • Gastric polyps.
  • EB (Epstein-Barr) virus
  • Familial syndromes (including familial adenomatous polyposis).
  • Eating a diet high in salty foods, smoked foods and low consumption of fruits and vegetables.
  • Eating foods that are not properly cooked or stored.
  • Advanced age or male.
  • Smoking.
  • Have a parent or sibling with stomach cancer.

    Signs of stomach cancer include indigestion, pain and discomfort in the stomach.

    These signs and other symptoms can be caused by stomach cancer or other diseases.

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

  • Indigestion as well as stomach discomfort
  • A feeling of bloating after eating.
  • Mild nausea.
  • Loss of appetite.
  • Heartburn sensation.

    Some of the following symptoms may occur in the middle and late stages of gastric cancer:

  • Blood in the stool
  • Vomiting
  • Unexplained weight loss
  • Stomach pain
  • Jaundice (yellowing of the eyes and skin)
  • ascites (accumulation of fluid in the abdominal cavity)
  • difficulty swallowing

    Consult your doctor if you have any of these problems.

    Gastric cancer is detected and diagnosed by an examination of the stomach and esophagus.

    Some of the following tests and procedures may be used:

  • Physical examination and history taking: A physical examination is performed to diagnose the health status of the body: this includes checking for symptoms of disease, such as lumps and other abnormalities. The patient’s hygiene habits, past medical history, and treatment history will also be taken.
  • Blood biochemistry: A blood sample is examined to measure the amount of certain substances that are released into the blood by organs and tissues in the body. Abnormal levels of a substance (above or below the normal range) may be a sign of disease.
  • Complete blood count (CBC): A blood sample is collected and then tested for.
  • Red blood cell, white blood cell, and platelet counts.
  • The amount of hemoglobin (the protein that carries oxygen) in the red blood cells.
  • The fraction of red blood cells in the blood sample.
  • Upper gastrointestinal endoscopy: An endoscopic examination of the esophagus, stomach, and duodenum (the first part of the small intestine) to check for abnormal areas. An endoscope (a thin, lighted tube) is used to pass through the mouth and into the esophagus through the pharynx.
    Upper gastrointestinal endoscopy. A thin, lighted tube is inserted through the mouth into the esophagus, stomach, and first part of the small intestine to examine abnormal areas.
  • Barium meal: A series of x-ray tests of the esophagus and stomach. The patient drinks a liquid containing barium (a silvery-white metallic mixture). This liquid covers the esophagus and stomach, and then an x-ray is performed. This procedure is also known as an upper GI test.
    The barium swallow for stomach cancer method. The patient swallows barium fluid, which passes through the esophagus into the stomach. X-rays are used to look for areas of abnormality.
  • CT scan (CAT scan): A series of detailed images of internal areas of the body (such as the chest, abdomen, and pelvis) taken from different angles. These images are generated by a computer attached to the x-ray machine. It may be necessary to inject a contrast agent into the blood vessels or swallow a contrast agent so that organs and tissues appear more clearly. This procedure is also known as computed tomography, or computed tomography or computed axial tomography.
  • Biopsy: Obtaining some cells or tissues and examining them under a microscope to look for evidence of cancer. A gastric biopsy is usually done during an endoscopy.

    Tissue samples can be examined to measure the HER2 gene as well as the amount of HER2 protein. If the HER2 gene or HER2 protein is higher than normal, the cancer is said to be HER2-positive. HER2-positive gastric cancer can be treated with a monoclonal antibody that targets the HER2 protein.

    Tissue specimens can also be checked for Helicobacter pylori (H. pylori) infection.

    Factors affecting prognosis (chance of recovery) and treatment options.

    Prognosis (chance of recovery) and treatment options depend on the following:

  • Stage of the cancer (whether the cancer is only in the stomach or has spread to the lymph nodes or other parts of the body).
  • The patient’s general health status.

    Gastric cancer has a better chance of recovery if it is detected early. Usually gastric cancer has progressed beyond the middle stage at the time of diagnosis. If it has progressed to an advanced stage, stomach cancer is difficult to be cured, although it can still be treated. Consider participating in some clinical trials to improve treatment. Information about clinical trials can be found in the Clinical Trials section of the NCI website.