Carcinoembryonic antigen (CEA)
Carcinoembryonic antigen (CEA) is a protein normally found in the tissue of a developing fetus. Levels of CEA in the blood decrease after birth. CEA is normally found in small amounts in the blood of most healthy people.
Why a CEA test is done
A CEA test may be done to:
- help diagnose and monitor a person’s response to treatment for certain cancers
- It is most commonly used for colorectal cancer.
- CEA may also be used for the following cancers:
- check if a cancer has come back (recurred)
How a CEA test is done
A CEA test is usually done in a private laboratory or hospital laboratory. No special preparation is usually needed.
- CEA is usually measured by a blood test.
- The sample is sent to a laboratory to be analyzed by special machines.
What the results mean
An increased CEA value may be due to:
- Smokers who do not have cancer can have an increased CEA value.
- non-cancerous conditions
- inflammatory bowel disease (such as colitis)
- benign breast disease
- benign ovarian disease
- inflammation of the pancreas (pancreatitis)
- liver disease (such as cirrhosis or hepatitis)
- chronic lung disease
- cancerous conditions
- colorectal cancer
- breast cancer
- lung cancer
- pancreatic cancer
- stomach cancer
- ovarian cancer
- bladder cancer
- thyroid cancer
- liver cancer
In cancerous conditions:
- A decrease in, or return to normal values of, CEA may mean that the cancer has responded well to treatment.
- An increase may mean that the cancer is not responding well to treatment, is still growing or is coming back (recurring).
- A slight increase may not be significant. Usually the doctor looks at trends in the increase over time.
What happens if a change or abnormality is found
The doctor will decide if more tests, procedures, follow-up care or additional treatment is needed.