Source: National Cancer Institute Research, www.cancer.gov
Screening is looking for cancer before a person has any symptoms. This can help find cancer at an early stage. When abnormaltissue or cancer is found early, it may be easier to treat. By the time symptoms appear, cancer may have begun to spread.
Scientists are trying to better understand which people are more likely to get certain types of cancer. They also study the things we do and the things around us to see if they cause cancer. This information helps doctors recommend who should be screened for cancer, which screening tests should be used, and how often the tests should be done.
It is important to remember that your doctor does not necessarily think you have cancer if he or she suggests a screening test. Screening tests are given when you have no cancer symptoms.
If a screening test result is abnormal, you may need to have more tests done to find out if you have cancer. These are called diagnostic tests.
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 3 layers of tissue: the mucosal (innermost) layer, the muscularis (middle) layer, and the serosal (outermost) layer. Stomach cancer begins in the cells lining the mucosal layer and spreads through the outer layers as it grows.
See the following PDQ summaries for more information about stomach cancer:
Stomach cancer is less common in the United States than in many parts of Asia, Europe, and Central and South America. Stomach cancer is a major cause of death in these parts of the world.
In the United States, the number of new cases of stomach cancer has greatly decreased since 1930. The reasons for this are not clear, but may have to do with better food storage and changes in the diet, such as lower salt intake.
Anything that increases the chance 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 to your doctor if you think you may be at risk for stomach cancer. Risk factors for stomach cancer include the following:
The risk of stomach cancer is increased in people who come from countries where stomach cancer is common.
Some screening tests are used because they have been shown to be helpful both in finding cancers early and in decreasing the chance of dying from these cancers. Other tests are used because they have been shown to find cancer in some people; however, it has not been proven in clinical trials that use of these tests will decrease the risk of dying from cancer.
Scientists study screening tests to find those with the fewest risks and most benefits. Cancer screening trials also are meant to show whether early detection (finding cancer before it causes symptoms) decreases a person's chance of dying from the disease. For some types of cancer, the chance of recovery is better if the disease is found and treated at an early stage.
Clinical trials that study cancer screening methods are taking place in many parts of the country. Information about ongoing clinical trials is available from the NCI Web site.
Several types of screening tests have been studied to find stomach cancer at an early stage. These screening tests include the following:
Studies showed that screening a large number of people for stomach cancer using these tests did not decrease the risk of dying from stomach cancer.
More studies are needed to find out if it would be worthwhile to screen people in the United States who do have a high risk for stomach cancer. Scientists believe that people with certain risk factors may benefit from stomach cancer screening. These include:
Decisions about screening tests can be difficult. Not all screening tests are helpful and most have risks. Before having any screening test, you may want to discuss the test with your doctor. It is important to know the risks of the test and whether it has been proven to reduce the risk of dying from cancer.
Screening may not improve your health or help you live longer if you have advancedstomach cancer.
Some cancers never cause symptoms or become life-threatening, but if found by a screening test, the cancer may be treated. It is not known if treatment of these cancers would help you live longer than if no treatment were given, and treatments for cancer may have serious side effects.
Screening test results may appear to be normal even though stomach cancer is present. A person who receives a false-negative result (one that shows there is no cancer when there really is) may delay seeking medical care even if there are symptoms.
Screening test results may appear to be abnormal even though no cancer is present. A false-positive test result (one that shows there is cancer when there really isn't) can cause anxiety and is usually followed by more tests and procedures which also have risks.
Upper endoscopy may cause the following rare, but serious, side effects: