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Who's at risk?
What are the symptoms?
How is it diagnosed?
What are the stages?
How is it treated?
How to help prevent stomach cancer
Who's at risk?
Each year about 22,000 people in the United States learn they have cancer of the stomach. Stomach cancer, also called gastric cancer, is the fourth most common cancer in the world today, although it is not nearly as common in this country as it was 60 years ago. Dietary changes and the greater use of refrigeration for food storage are credited for the lower incidence of stomach cancer.
Scientists don't know why some people develop stomach cancer and others don't. But they do know that some people are more likely than others to develop it. For instance, stomach cancer occurs mostly in men older than 40 and is more likely to occur in black people than in white people.
There are other factors that can increase the risk of getting stomach cancer:
Helicobacter pylori (H. pylori). Some studies suggest that a type of bacteria, Helicobacter pylori, which lives in the stomach lining, is a major cause of stomach cancer. It is found in 20 percent of people age 40 and younger and 50 percent of those who are 60 or older. H. pylori bacteria often cause peptic ulcers. However, stomach ulcers do not appear to raise a person's risk of developing stomach cancer. People with H. pylori infection have three to eight times greater risk of developing gastric cancer than those not infected, although most never develop stomach cancer.
Diet. A diet high in preserved foods - such as those that are smoked, dried, salted or pickled - that contain nitrates and nitrites are linked to stomach cancer. These substances can be converted inside your stomach into compounds that increase your risk of stomach cancer. Researchers have also found people who have diets rich in meat, cheese and whole milk may be at increased risk of developing cancer in both the esophagus and stomach.
Previous stomach surgery. Stomach surgery may result in higher levels of nitrite-producing bacteria and bile in your stomach, which increases the risk of stomach cancer.
Stomach polyps. Polyps are small bumps or larger mushroom-like growths of the lining of the stomach. Most types of polyps (such as hyperplastic polyps or inflammatory polyps) do not increase a person's risk of stomach cancer, but adenomatous, or benign polyps, sometimes develop into stomach cancers.
Pernicious anemia. Pernicious anemia is caused by a lack of a substance needed to absorb vitamin B12. Vitamin B12 helps form red blood cells. Anemia is when red blood cells are not giving enough oxygen to body tissues. People with this condtion may have gastric polyps and twice the rate of stomach cancer than those without pernicious anemia. Older adults are more likely to have this condition.
Genetics. Stomach cancers are two to four times more common for immediate family members of those who have had the disease. However, more than 90 percent of people with stomach cancer don't have family members with stomach cancer.
Country of origin. Stomach cancer is more common in some parts of the world - such as Japan, Korea, parts of Eastern Europe and Latin America - than in the United States. Researchers believe people in these areas eat many foods that are preserved by drying, smoking, salting or pickling.
Smoking and alcohol abuse. Both of these substances can irritate the lining of the stomach, particularly the upper parts, and increase the risk of developing cancer.
Environmental exposure. Certain dusts and fumes in the workplace have been linked to a higher-than-average risk of stomach cancer.
What are the symptoms?
Stomach cancer can cause the following symptoms:
- Indigestion or a burning sensation (heartburn).
- Discomfort or pain in the abdomen.
- Nausea and vomiting.
- Diarrhea or constipation.
- Bloated feeling after meals or feeling full faster when eating.
- Loss of appetite.
- Weakness and fatigue.
- Bleeding (vomiting blood or having blood in the stool).
- Black, tarry stools.
Any of these problems could be caused by less serious health problems as well. Symptoms should prompt the patient to see the doctor, who may then refer that patient to a gastroenterologist, a doctor who specializes in diagnosing and treating digestive problems.
How is it diagnosed?
To find the cause of your symptoms, the doctor will ask for a medical history, do a physical exam and will order laboratory tests. They may include one or all of the following exams:
Fecal occult blood test - A check for hidden (occult) blood in the stood. This test is done by placing a small amount of stool on a plastic slide or on a special paper. It may be tested in the doctor's office or sent to a laboratory for the presence of blood.
This test is done because stomach cancer sometimes causes bleeding that cannot be seen. However, noncancerous conditions may also cause bleeding, such as hiatal hernia, gastroesophageal reflux disease or stomach ulcers. Bleeding can also come from the esophagus, small intestine, colon, rectum or hemorrhoids. So having blood in the stool doesn't mean that you have cancer.
Upper GI series - X-rays of the "GI tract" - the esophagus (which connects your throat and stomach) and stomach. After fasting the night before, the patient drinks a thick, chalky barium liquid. The barium outlines the stomach on the X-rays, helping the doctor find tumors or other abnormal areas. The problem with the X-ray study is that it rarely reveals small, early tumors. The doctor may pump air into the stomach to make such small tumors easier to see.
Endoscopy - An exam of the esophagus and stomach using a thin, lighted tube called an endoscope (also called a gastroscope). Endoscopy is the best diagnostic procedure because it allows the doctor to see the stomach. A local anesthetic is first sprayed into your throat to reduce discomfort and gagging. You may also receive medication to relax you. Your doctor then inserts a thin, flexible tube (endoscope) equipped with a light through your mouth and into your esophagus, stomach and small intestine. Your doctor will be able to see the upper part of your digestive tract and remove a small sample (biopsy) of any tissue that appears abnormal for further assessment. The tissue sample is sent to a pathologist who examines it under a microscope to check for cancer cells. A biopsy is the only sure way to know whether cancer cells are present. Pictures or videos can also be taken during an endoscopy.
If a diagnosis of stomach cancer is made, your doctor will recommend additional tests to determine the extent of the cancer and the best treatment. These tests may include:
Endoscopic ultrasound. Using an endoscope, the doctor can thread a small ultrasound device into the stomach to get a close-up image of it on a computer screen. Endoscopic ultrasound is also used to detect any enlarged lymph nodes near your esophagus or stomach that are suspicious for cancer involvement.
Computerized tomography (CT) scan. These are done on the chest, abdomen and pelvis.
PET scan. A PET scan may also be performed. This stands for positron emission tomography, and is an imaging technique that detects subtle changes in the body's metabolism. A PET scan may determine if a tumor is benign or malignant and can show if a malignant tumor has spread. It can also help determine the staging of cancers.
What are the stages?
The four stages of stomach cancer progression are:
Stage 1: Cancer cells are confined to only the inner stomach lining. They are absent from the wall of the stomach or from lymph nodes.
Stage 2: Cancer cells exist in the tissue of the second or third layers of the gastric wall, and may or may not exist only in the lymph nodes and has not spread to other areas.
Stage 3: Cancer cells have spread (metastasized) to other areas adjacent to the stomach.
Stage 4: Cancer cells have metastasized to distant organs.
How is it treated?
Treatment for stomach cancer depends on the size, location and extent of the tumor; whether the cancer has spread and, if so, what parts of the body are affected; the patient's general health; and other factors.
Treatment may include surgery, chemotherapy and/or radiation therapy. New treatment approaches such as biological therapy and improved ways of using current methods are being studied in clinical trials. A patient may have one form of treatment or a combination of treatments.
Surgery. Surgical removal of the stomach tumor is the most common treatment for stomach cancer and can lead to a cure. In the operation (called a gastrectomy), the surgeon removes part (subtotal or partial gastrectomy) or all (total gastrectomy) of the stomach, as well as some of the tissue around the stomach. After a subtotal gastrectomy, the surgeon connects the remaining part of the stomach to the esophagus or the small intestine. After a total gastrectomy, he or she connects the esophagus directly to the small intestine. Lymph nodes near the tumor are removed during surgery so they can be checked for cancer cells. The presence of cancer cells in the lymph nodes tells doctors that the disease may have spread to other parts of the body. The liver is also carefully examined and often an ultrasound of the liver at surgery is done.
Chemotherapy. In chemotherapy, anticancer drugs are given to kill cancer cells. These drugs work on cancer cells wherever they are in the body, not just in the stomach. They can be taken orally or given by injection. Chemotherapy is sometimes used before surgery (neoadjuvant chemotherapy) to shrink the tumor, or after surgery (adjuvant chemotherapy) to destroy remaining cancer cells. Palliative chemotherapy is given in order to alleviate symptoms and to prolong life for patients whose stomach cancer has spread (metastasized) to distant parts of the body or cannot be removed surgically for other reasons. Doctors are also testing a treatment in which cancer-killing drugs are administered directly into the abdomen. Commonly used programs include intraveneous flourouracil (5-FU) combined with adriamycin [FAMTX] and mitomycin-C; ELF (etoposide, leucovorin, 5-FU); or adriamycin and cisplatin. Chemotherapy is given in cycles: a treatment period followed by a recovery period, then another treatment, and so on. Current research programs including ECF (epirubicin + cisplatin + 5-FU) have had superior results compared with adriamycin and methotrexate or cisplatin/5-FU. Recent programs using irinotecan (Camptosar®) and Paclitaxal with 5-FU and cisplatin have shown remissions.
Radiation therapy. Radiation therapy uses high-energy rays to kill cancer cells in the body. The radiation is delivered from outside the body and is directed at the specific area focusing on the cancer. Radiation therapy is used to kill very small cancer cells that could not be seen and removed during surgery. It is also used to ease the pain, bleeding and difficulty eating caused by advanced stomach cancer.
Newer methods of local "spot" reduction for small brain or body tumors include Gamma Knife® and CyberKnife® research methods to help deliver a small focal field. These devices are available at a few large cancer centers.
Despite its name, the Gamma Knife isn't a knife. Rather, it's a single, finely focused, high dose of radiation precisely targeting the tumor with little or no damage to surrounding tissue.
The CyberKnife is a painless, non-invasive therapy that delivers high doses of precisely targeted radiation to destroy tumors or lesions within the body. A robotic arm delivers highly focused beams of radiation. The flexibility of the robotic arm makes it possible to treat areas such as the spine and spinal cord that cannot be treated by other radiosurgery techniques.
Chemoradiation therapy. Chemoradiation, an approach that has shown promise in clinical trials, uses a combination of chemotherapy and radiotherapy for patients who have undergone a gastrectomy (adjuvant chemoradiation). These are patients from whom the stomach tumor appears to have been removed entirely during surgery, but whose disease is at risk for recurrence.
How can I help prevent stomach cancer?
- Avoid diets that are high in smoked and pickled foods and salted meats and fish.
- Eat a diet high in fresh fruits and vegetables. The American Cancer Society recommends that people choose most of the foods they eat from plant sources. This includes fruits, vegetables, breads, cereals, pasta, rice and beans.
- Limit alcohol to one or two drinks or cut out alcohol.
This article was reviewed and updated June 2007.
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