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Primarily to monitor cancer treatment, including response to therapy and recurrence; as an indicator of the amount of cancer or size of tumor present (tumor burden) and to assist in cancer staging; occasionally as follow up to a positive screening test for cancer, to compare whether the level falls to normal (indicating that the cancer was all likely removed) after treatment for the cancer
When you have been diagnosed with colon, pancreas, breast, lung, ovarian, medullary thyroid or other cancer prior to starting cancer treatment and then, if elevated, at intervals during and after therapy; occasionally when cancer is suspected but not confirmed – to aid in its detection
A blood sample is taken by needle from a vein in the arm. Occasionally, another body fluid such as peritoneal fluid, pleural fluid, or cerebrospinal (CSF) is collected by a healthcare practitioner for testing.
Carcinoembryonic antigen (CEA) is a protein that is present in certain tissues of a developing baby (fetus). By the time a baby is born, it drops to a very low level. In adults, CEA is normally present at very low levels in the blood but may be elevated with certain types of cancer. This test measures the amount of CEA in the blood to help evaluate individuals diagnosed with cancer.
CEA is a tumor marker. Originally, it was thought that CEA was a specific marker for colon cancer, but further study has shown that an increase in CEA may be seen in a wide variety of other cancers. CEA can also be increased in some non-cancer-related conditions, such as inflammation, cirrhosis, peptic ulcer, ulcerative colitis, rectal polyps, emphysema, and benign breast disease, and in smokers. For this reason, it is not useful as a general cancer screening tool, but it does have a role in evaluating response to cancer treatment. When you have been diagnosed with cancer, an initial baseline test for CEA may be performed. If this level is elevated, then subsequent serial testing of CEA may be performed to monitor the cancer during treatment.
The carcinoembryonic antigen (CEA) test may be used:
A CEA test may be used in combination with other tumor markers in the evaluation of cancer.
Not all cancers produce CEA, and a positive CEA test is not always due to cancer. Therefore, CEA is not recommended for screening the general population.
A CEA test may be ordered when you have been diagnosed with colon cancer or other specific type of cancer. It will be measured before therapy is initiated and then on a regular basis to evaluate the success of treatment and to determine whether the cancer has come back after treatment (recurrence).
Sometimes a CEA test may be performed when cancer is suspected but not yet diagnosed. This is not a common use for the test because CEA can be elevated with many conditions, but it may provide a healthcare practitioner with additional information.
For treatment, recurrence monitoring:
When CEA levels are initially elevated and then decrease to normal after therapy, it means the cancer has been successfully treated. A steadily rising CEA level is often the first sign of tumor recurrence.
On initial testing, people with smaller and early-stage tumors are likely to have a normal or only slightly elevated CEA value. People with larger tumors, later-stage cancer, or tumors that have spread throughout the body are more likely to have a high CEA value.
Testing for metastasis:
If CEA is present in a body fluid other than blood, then cancer is likely to have spread into that area of the body. For example, if CEA is detected in cerebrospinal fluid, this may indicate that cancer has spread to the central nervous system.
Since not all cancers produce CEA, it is possible to have cancer but also have a normal CEA. If a cancer does not produce CEA, then the test will not be useful as a monitoring tool.
Not necessarily. Smokers can have CEA values up to twice the normal range for non-smokers and not have cancer.
No. CEA has a role to play in certain tumors, particularly colon cancer. However, a number of other tumor markers have been developed to monitor cancers from different areas of the body. As an example, breast cancer is usually monitored with a CA 15-3 test or a CA 27.29 test. For some cancers, testing for tumor markers is not done at all.
A CEA blood test typically has no associated risk. Very mild pain and bruising may occur at the site where blood was collected using a needle. To assess metastasis, fluid can be collected from other sites. For example, pleural fluid may be collected from the area surrounding the lungs. This procedure has a small risk of lung injury, bleeding, or infection. When peritoneal fluid (the liquid in the abdomen filling the sacs surrounding the intestine) is collected to assess abdominal metastasis, there may be a small risk of damage to the intestine or other organs. You may also feel pain and dizziness after the procedure. To assess brain metastasis, CSF will be collected by a spinal tap (lumbar puncture) to measure the CEA. With this procedure, back pain or tenderness at the needle insertion might happen, and a post lumbar headache or dizziness might occur.
Laboratories may use different methods to test for CEA, so results can vary from lab to lab. If you are having a series of CEA tests done, it is advised that you have the tests done by the same method, typically by the same laboratory, so that the results can be compared and interpreted correctly. You may wish to discuss this issue with your healthcare provider.
Individuals who smoke cigarettes tend to have higher CEA levels than non-smokers.
Increased CEA levels can indicate some non-cancer-related conditions, such as inflammation, cirrhosis, peptic ulcer, ulcerative colitis, rectal polyps, emphysema, and benign breast disease.
Sources Used in Current Review
2020 review performed by Imad Tarhoni, MD, PhD.
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Hall C, Clarke L, Pal A, Buchwald P, Eglinton T, Wakeman C, Frizelle F: A Review of the Role of Carcinoembryonic Antigen in Clinical Practice. Ann Coloproctol 2019, 35:294-305.
© 1995–2020. Mayo Foundation for Medical Education and Research. Carcinoembryonic Antigen (CEA), Serum. Available online at https://www.mayocliniclabs.com/test-catalog/Overview/8521. Accessed May 2020.
Sources Used in Previous Reviews
Clarke, W. and Dufour, D. R., Editors (2006). Contemporary Practice in Clinical Chemistry, AACC Press, Washington, DC. Pp 244-245.
Pagana K, Pagana T. Mosby's Manual of Diagnostic and Laboratory Tests. 3rd Edition, St. Louis: Mosby Elsevier; 2006 pp 161-162.
MedlinePlus Medical Encyclopedia: CEA. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003574.htm. Accessed February 2009.
(Revised 2012 January 20). How is Thyroid Cancer Diagnosed? American Cancer Society [On-line information]. Available online at http://www.cancer.org/Cancer/ThyroidCancer/DetailedGuide/thyroid-cancer-diagnosis. Accessed October 2012.
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(Revised 2012 October 1). How is colorectal cancer diagnosed? American Cancer Society. [On-line information]. Available online at http://www.cancer.org/Cancer/ColonandRectumCancer/DetailedGuide/colorectal-cancer-diagnosed. Accessed October 2012.
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(Revised 2011 March 24). Common cancers and the tumor markers linked to them. American Cancer Society [On-line information]. Available online through http://www.cancer.org. Accessed October 2012.
(Reviewed 2011 December 30). Tests to Detect Colorectal Cancer and Polyps. National Cancer Institute. [On-line information]. Available online at http://www.cancer.gov/cancertopics/factsheet/detection/colorectal-screening. Accessed October 2012.
Pagana, K. D. & Pagana, T. J. (© 2011). Mosby's Diagnostic and Laboratory Test Reference 10th Edition: Mosby, Inc., Saint Louis, MO. Pp 223-224.
Clarke, W., Editor (© 2011). Contemporary Practice in Clinical Chemistry 2nd Edition: AACC Press, Washington, DC. Pp 244-245.
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U.S. National Library of Medicine (1 August 2015 updated). CEA Blood Test. Available online at https://www.nlm.nih.gov/medlineplus/ency/article/003574.htm. Accessed June 28, 2016.
Penn Medicine Oncolink® (28 April 2016 updated). Patient Guide to Tumor Markers. Available online at http://www.oncolink.org/treatment/article.cfm?id=296. Accessed June 28, 2016.
National Cancer Institute (4 November 2015 reviewed). Tumor Markers. Available online at http://www.cancer.gov/about-cancer/diagnosis-staging/diagnosis/tumor-markers-fact-sheet. Accessed June 28, 2016.
American Cancer Society (6 March 2014 updated). How Is Advanced Cancer Found? Available online at http://www.cancer.org/treatment/understandingyourdiagnosis/advancedcancer/advanced-cancer-diagnosis. Accessed June 28, 2016.