Tests are used to screen for different types of cancer.
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.
The age-adjusted incidence of carcinoid tumors worldwide is approximately 2 per 100,000 persons.[1,2] The average age at diagnosis is 61.4 years. Carcinoid tumors represent about 0.5% of all newly diagnosed malignancies.[2,3]
Carcinoid tumors are rare, slow-growing tumors that originate in cells of the diffuse neuroendocrine system. They occur most frequently in tissues derived from the embryonic gut. Foregut tumors, which account for up to 25% of cases, arise...
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.
There is no standard or routine screening test for liver cancer.
Although there are no standard or routine screening tests for liver cancer, the following tests are being used or studied to screen for it:
Ultrasound is a procedure in which high-energy sound waves (ultrasound) are bounced off the liver and make echoes. The echoes form a picture of the liver called a sonogram. The picture can be printed to be looked at later.
CT scan is a procedure that makes a series of detailed pictures of the liver, 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 liver show up more clearly. This procedure is also called CAT scan or computed tomography.
Tumor markers, also called biomarkers, are substances made by the tumor that may be found in the blood, other body fluids, or tissues. A high level of a specific tumor marker may mean that a certain type of cancer is present in the body.
Alpha-fetoprotein (AFP) is the most widely used tumor marker for detecting liver cancer. However, other cancers and certain conditions, including pregnancy, hepatitis, and other types of cancer, may also increase AFP levels.
Specific tumor markers that may lead to early detection of liver cancer are being studied.
Information about ongoing clinical trials is available from the NCI Web site.
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This information is produced and provided by the National
Institute (NCI). The information in this topic may have changed since it was written. For the most current information, contact the National
Institute via the Internet web site at http://
.gov or call 1-800-4-CANCER.
WebMD Public Information from the National Cancer Institute
September 04, 2014
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