The CEA test (from English Carcino-Embryonic Antigen) measures the level in the blood of the carcinoembryonic antigen, a protein found in some tissues of the fetus. From birth onwards, CEA decreases in quantity until reaching very low blood concentrations in the adult.
The exam consists of taking a small amount of blood by inserting a needle into a vein in the arm. Occasionally, it can be performed on other body fluids, such as the fluid that is between the two membranes that line the wall and organs of the abdomen (peritoneal fluid), the fluid that is between the two membranes that line the chest wall and the lungs (pleural fluid), the fluid found in the meninges and outside the spinal cord (cerebrospinal fluid).
CEA concentrations in the blood may increase in people with certain cancers but also in other diseases such as cirrhosis, hepatitis, stomach ulcer (peptic ulcer), pancreatitis, ulcerative colitis and Crohn's disease , emphysema and hypothyroidism. Furthermore, its values may be higher in benign breast diseases, smokers and inflammations. For these reasons, the CEA is not useful for ascertaining (diagnosing) the presence of a tumor but has a role in evaluating the effectiveness of treatment in people who are already ill and for monitoring its progress over time.The measurement of CEA values in the blood is also used as a supportive analysis in the clinical evaluation of individuals with certain types of cancer (most commonly, colon, breast, liver, lung, stomach, pancreatic cancers).
Doctors mainly use the CEA measurement:
- to monitor the response to therapies and the possible reappearance (relapse) of the tumor
- as an indicator of the size of the tumor mass present (tumor burden)
- as an aid in determining how advanced the disease is (staging) and what will be its probable evolution (prognosis)
- to detect the spread of the tumor (metastasis)
Typically, when a person is diagnosed with cancer, an initial CEA measurement is taken. If the concentration is high, periodic measurements are performed to check the progress of the disease and the response to treatment. If the tumor does not produce CEA, the test is not useful in the control program.
When to take the test
Following the detection (diagnosis) of cancer of the colon, pancreas, breast, lung, ovary, medullary portion of the thyroid gland or other types of cancer, before starting the treatment (therapy) performs the test Subsequently, in case of high CEA levels, the test is repeated at regular intervals during and after therapy.
Sometimes, it may be requested when the presence of cancer is suspected but not yet ascertained, to aid in research. It is not a frequent use as the level of CEA in the blood can be elevated due to other diseases and disorders. However, the test can still provide the doctor with additional information.
The measurement of CEA, if the doctor suspects that the tumor has spread remotely, can also be performed on other body fluids other than blood, such as, for example, the fluid that is between the membranes that line the chest wall and the lungs (pleural sheets), between the membranes that line the abdominal wall and organs (peritoneal fluid) or the fluid found in the meninges and outside the spinal cord (cerebrospinal fluid).
Meaning of the test results
Any result obtained from the CEA measurement must always be subjected to the evaluation of the treating physician who, knowing the person's state of health, the treatments carried out and / or the course of the disease, is the only one able to interpret it correctly. In general, when the test is used to check the efficacy of the therapy and to check for the appearance of any relapses of tumors, the progressive reduction and normalization of CEA values after treatment indicates that the tumor has been successfully fought. A constant increase in it after the therapies (found in measurements performed several times) is often the first sign that the tumor has appeared again (relapse).
In the case of dosing of CEA in other body fluids (peritoneal fluid, pleural fluid, cerebrospinal fluid) its presence indicates the spread of the tumor in that area of the body (tumor metastases). For example, the presence of CEA in the fluid cerebrospinal, may be a sign of metastasis to the central nervous system.