Gastric Cancer

General Information | Treatment Options | Screening
Prevention | Additional Resources

General Information
  • About
  • Risk Factors
  • Signs & Symptoms
  • Detection
  • Stages

General Information About Gastric Cancer

Gastric cancer is a disease in which malignant (cancer) cells form in the lining of the stomach.

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 stomach and esophagus are part of the upper digestive system.

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. See the PDQ summary on Adult Soft Tissue Sarcoma Treatment for more information.

For more information about cancers of the stomach, see the following PDQ summaries:

  • Unusual Cancers of Childhood
  • Stomach (Gastric) Cancer Prevention
  • Stomach (Gastric) Cancer Screening
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. People who think they may be at risk should discuss this with their doctor. 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).
    • Familial adenomatous polyposis (FAP) or gastric polyps.
  • 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.
Possible signs of gastric cancer include indigestion and stomach discomfort or pain.

These and other symptoms may be caused by gastric cancer. Other conditions may cause the same symptoms.

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 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.

A doctor should be consulted if any of these problems occur.

Tests that examine the stomach and esophagus are used to detect (find) and diagnose gastric cancer.

The following tests and procedures may be used:

  • Physical exam and 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 in the organ or tissue that produces it.
  • 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.
    Upper endoscopy. A thin, lighted tube is inserted through the mouth to look for abnormal areas in the esophagus, stomach, and first part of the small intestine.
  • Fecal occult blood test: A test to check stool (solid waste) for blood that can only be seen with a microscope. Small samples of stool are placed on special cards and returned to the doctor or laboratory for testing.
  • Barium swallow: A series of x-rays of the esophagus and stomach. The patient drinks a liquid that contains barium (a silver-white metallic compound). The liquid coats the esophagus and stomach, and x-rays are taken. This procedure is also called an upper GI series.
    Barium swallow. The patient swallows barium liquid and it flows through the esophagus and into the stomach. X-rays are taken to look for abnormal areas.
  • Biopsy: The removal of cells or tissues so they can be viewed under a microscope to check for signs of cancer. A biopsy of the stomach is usually done during the endoscopy.
  • CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.
Certain factors affect prognosis (chance of recovery) and treatment options.

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

  • The stage and extent of the cancer (whether it is in the stomach only or has spread to lymph nodes or other places in the body).
  • The patient’s general health.

When gastric cancer is found very early, there is a better chance of recovery. Gastric cancer is often in an advanced stage when it is diagnosed. At later stages, gastric cancer can be treated but rarely can be cured. Taking part in one of the clinical trials being done to improve treatment should be considered. Information about ongoing clinical trials is available from the NCI Web site.

Stages of Gastric Cancer

After gastric cancer has been diagnosed, tests are done to find out if cancer cells have spread within the stomach or to other parts of the body.

The process used to find out if cancer has spread within the stomach or to other parts of the body is called staging. The information gathered from the staging process determines the stage of the disease. It is important to know the stage in order to plan treatment.

The following tests and procedures may be used in the staging process:

  • β-hCG (beta-human chorionic gonadotropin), CA-125, and CEA (carcinoembryonic antigen) assays: Tests that measure the levels of β-hCG, CA-125, and CEA in the blood. These substances are released into the bloodstream from both cancer cells and normal cells. When found in higher than normal amounts, they can be a sign of gastric cancer or other conditions.
  • Chest x-ray: An x-ray of the organs and bones inside the chest. An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body.
  • Endoscopic ultrasound (EUS): A procedure in which an endoscope is inserted into the body, usually through the mouth or rectum. An endoscope is a thin, tube-like instrument with a light and a lens for viewing. A probe at the end of the endoscope is used to bounce high-energy sound waves (ultrasound) off internal tissues or organs and make echoes. The echoes form a picture of body tissues called a sonogram. This procedure is also called endosonography.
  • CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.
  • Laparoscopy: A surgical procedure to look at the organs inside the abdomen to check for signs of disease. Small incisions (cuts) are made in the wall of the abdomen and a laparoscope (a thin, lighted tube) is inserted into one of the incisions. Other instruments may be inserted through the same or other incisions to perform procedures such as removing organs or taking tissue samples for biopsy.
  • PET scan (positron emission tomography scan): A procedure to find malignant tumor cells in the body. A small amount of radioactive glucose (sugar) is injected into a vein. The PET scanner rotates around the body and makes a picture of where glucose is being used in the body. Malignant tumor cells show up brighter in the picture because they are more active and take up more glucose than normal cells do.
There are three ways that cancer spreads in the body.

The three ways that cancer spreads in the body are:

  • Through tissue. Cancer invades the surrounding normal tissue.
  • Through the lymph system. Cancer invades the lymph system and travels through the lymph vessels to other places in the body.
  • Through the blood. Cancer invades the veins and capillaries and travels through the blood to other places in the body.

When cancer cells break away from the primary (original) tumor and travel through the lymph or blood to other places in the body, another (secondary) tumor may form. This process is called metastasis. The secondary (metastatic) tumor is the same type of cancer as the primary tumor. For example, if breast cancer spreads to the bones, the cancer cells in the bones are actually breast cancer cells. The disease is metastatic breast cancer, not bone cancer.

The following stages are used for gastric cancer:Stage 0 (Carcinoma in Situ)

In stage 0, abnormal cells are found in the inside lining of the mucosal (innermost) layer of the stomach wall. These abnormal cells may become cancer and spread into nearby normal tissue. Stage 0 is also called carcinoma in situ.

Stage I

In stage I, cancer has formed. Stage I is divided into stage IA and stage IB, depending on where the cancer has spread.

  • Stage IA: Cancer has spread completely through the mucosal (innermost) layer of the stomach wall.
  • Stage IB: Cancer has spread:
    • completely through the mucosal (innermost) layer of the stomach wall and is found in up to 6 lymph nodes near the tumor; or
    • to the muscularis (middle) layer of the stomach wall.
Stage II

In stage II gastric cancer, cancer has spread:

  • completely through the mucosal (innermost) layer of the stomach wall and is found in 7 to 15 lymph nodes near the tumor; or
  • to the muscularis (middle) layer of the stomach wall and is found in up to 6 lymph nodes near the tumor; or
  • to the serosal (outermost) layer of the stomach wall but not to lymph nodes or other organs.
Stage III

Stage III gastric cancer is divided into stage IIIA and stage IIIB depending on where the cancer has spread.

  • Stage IIIA: Cancer has spread to:
    • the muscularis (middle) layer of the stomach wall and is found in 7 to 15 lymph nodes near the tumor; or
    • the serosal (outermost) layer of the stomach wall and is found in 1 to 6 lymph nodes near the tumor; or
    • organs next to the stomach but not to lymph nodes or other parts of the body.
  • Stage IIIB: Cancer has spread to the serosal (outermost) layer of the stomach wall and is found in 7 to 15 lymph nodes near the tumor.
Stage IV

In stage IV, cancer has spread to:

  • organs next to the stomach and to at least one lymph node; or
  • more than 15 lymph nodes; or
  • other parts of the body.

Recurrent Gastric Cancer

Recurrent gastric cancer is cancer that has recurred (come back) after it has been treated. The cancer may come back in the stomach or in other parts of the body such as the liver or lymph nodes.

Cancer information from the NCI PDQ service