A CEA test is used to help diagnose certain types of cancer in combination with other tests, to monitor the treatment thereof and to detect recurrence of those cancers. The test is a simple blood test done on blood drawn from the vein. Results can be returned in one to three days and may indicate the presence of cancer, although raised levels are occasionally found in patients with some non-cancerous conditions.
CEA is the abbreviation of carcinoembryonic antigen, a protein that is produced in the fetus but is no longer detectable once the baby is born. The protein is mainly produced by some cancerous tumors of the colon, rectum, intestine, breast, pancreas, ovary and lung. Some tumors do not produce it at all, so a CEA test that shows nothing is not a guarantee that cancer is not present. Various other blood tests and, in some cases, a biopsy may be necessary to confirm cancer.
While a CEA test is often used for diagnosis in combination with other diagnostic tests, it is not used as an indicator of cancer in the healthy population. It is usually only ordered in patients showing symptoms that may indicate the presence of cancer. It is also used to indicate the success of cancer treatment in patients who have had surgery to remove a tumor and in those undergoing treatment, such as chemotherapy. In patients who have been successfully treated and are in remission, a CEA test may routinely be done to check for recurrence of cancer.
Some non-cancerous conditions may also cause a raised CEA. These include liver cirrhosis, kidney failure, peptic ulcer disease, chronic obstructive pulmonary disease (COPD) and Crohn's disease. Smokers may also have raised CEA levels even if they do not have cancer. It should also be noted that a CEA test that shows nothing may not, necessarily, indicate that no cancer is present, as some tumors don't produce the hormone.
Other blood tests that may be performed concurrent to the CEA test in people with suspected cancer include other tumor marker tests, such as the prostate specific antigen (PSA) for prostate cancer. Often a biopsy is necessary for confirmation of diagnosis and determination of whether the tumor is benign or malignant. This is a small procedure done either under local or general anesthetic, depending on where the tumor is. A small number of cells or tissue is removed and examined for the presence of cancer cells.