Carcinoembryonic Antigen (CEA)

The carcinoembryonic antigen (CEA) test may be used:

• To monitor the treatment of people diagnosed with colon cancer. It may also be used as a marker for medullary thyroid cancer and cancers of the rectum, lung, breast, liver, pancreas, stomach, and ovaries. An initial CEA test is typically ordered prior to treatment as a "baseline" value. If the level is elevated, then the test can be used to monitor a person's response to therapy and to determine whether the cancer has progressed or recurred.
• To stage cancer—cancer staging involves evaluating the size of the tumor as well as how far it has spread.
• Testing CEA in a body fluid sample may help to determine if cancer has spread to a body cavity such as the chest or abdomen (pleural or peritoneal cavity).

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 a person has been diagnosed with colon cancer or other specific types of cancer. It will be measured before therapy is initiated and then on a regular basis to evaluate the success of treatment and to detect 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.

A CEA test may sometimes be performed on a fluid other than blood when a healthcare practitioner suspects that a cancer has metastasized (e.g., spread to the pleural or peritoneal cavity).

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.

For staging:
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 the person's 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.

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.

Not necessarily. Smokers can have CEA values up to twice the normal range for non-smokers and not have cancer.