In the presence of certain cancers, carcinoembryonic antigen (CEA) may be used to monitor the effect of treatment and recurrance of disease
Before starting cancer treatment as well as at intervals during and after therapy
A blood sample drawn from a vein in the arm
CEA is a protein that is normally not detected in the blood of a healthy person. When certain types of cancer are present, CEA may be produced by the cancer cells. CEA may then be detected in blood, but it will not indicate which kind of cancer is present. CEA is often used to monitor patients with cancers of the gastrointestinal (GI) tract such as colorectal cancer. It may be raised in other cancers, such as ovarian and breast cancers, but can also be raised in benign conditions such as liver disease and inflammatory bowel disease (Crohn's disease or ulcerative colitis).
A blood sample is taken by needle from the arm.
No test preparation is needed.
CEA is most useful to monitor treatment of cancer patients. It is used for patients who have had surgery, to measure response to therapy and to monitor whether the disease has recurred. A blood test for CEA in this circumstance is used as a tumour marker, i.e. an indicator of whether the cancer is present or not. CEA is used as a marker for bowel cancer in particular, but may be measured where other forms of cancer are present. It has been found helpful in monitoring some patients with cancer of the rectum, lung, breast, liver, pancreas, stomach, and ovary. Not all cancers produce CEA, and a level within the given reference range does not guarantee that cancer (even the kinds known to produce CEA) is not present, therefore the CEA test is not used for screening the general population.
A CEA test may be requested when the patient's symptoms suggest the possibility of cancer. CEA is most useful when measured in patients with cancers known to produce the protein and can be used to monitor patients before and during or after treatment.
The level of CEA in the blood does not accurately reflect tumour size, however on initial testing, patients with smaller and early-stage tumours are likely to have low, if not normal, CEA levels, while patients with more advanced tumours, or tumours that have spread throughout the body, are likely to have initially high CEA levels. When CEA levels decrease to "normal" levels after therapy, it means that the CEA-producing tumour has been removed. A steadily rising CEA level may be the first sign that the cancer has returned.
CEA is a protein that is found in developing tissues of babies. By the time a baby is born, detectable levels in the blood disappear.
Increased CEA levels can indicate some non-cancer-related conditions, such as liver disease, and inflammatory bowel disease. Also, smokers tend to have higher CEA levels than non-smokers.
Conditions: Bowel cancer
RCPA Manual: Carcinoembryonic Ag
MedicineNet: Carcinoembryonic Antigen
Last Review Date: March 25, 2021