• CEA (carcinoembryonic antigen) is a type of tumour marker. Tumour markers are substances made by cancer cells or by normal cells in response to cancer.
• Measuring levels of CEA in the blood or other bodily fluids is used along with other tests to monitor treatment for cancer and to check that a treated cancer has not returned.
• CEA is most often used in cancers of the gastrointestinal (GI) tract such as bowel cancer, but also lung, breast, ovarian, stomach, pancreatic and some other cancers.
• CEA is usually measured in the blood but other fluids including peritoneal fluid, a liquid in the abdominal cavity which reduces friction between organs, are sometimes used.

CEA (carcinoembryonic antigen) is a protein found in very small amounts in the tissue of babies in the womb. By the time the baby is born, CEA is no longer able to be detected in the blood.

Healthy adults produce little or no CEA, but levels are higher in people with chronic inflammatory conditions such as chronic liver disease, inflammatory bowel disease such as Crohn’s disease and ulcerative colitis and chronic lung disease.

When levels are very high, this is strongly suggestive of cancer. CEA testing is most often used to monitor people with cancers of the gastrointestinal (GI) tract such as bowel (colorectal) cancer. It can also be measured to monitor other cancers, including breast, lung, ovarian, stomach and pancreatic cancers.

Not all cancers produce CEA and having a normal result does not guarantee that cancer is not present.

CEA testing cannot be used to diagnose a specific type of cancer or show where a cancer is located. This is because many other non-cancerous conditions can cause CEA levels to rise. Also, some people can have a cancer, and their CEA levels stay normal.

CEA testing is most useful in monitoring people after their treatment such as surgery, chemotherapy or radiotherapy to check the progress of treatment and to make sure that the cancer has not returned. Typically, CEA levels return to normal within a few weeks following successful surgery.

A CEA test is performed at the time of diagnosis when the level is recorded as a baseline measurement so that future CEA levels taken during and after treatment can be compared. An increase or decrease in CEA levels during treatment can help decide whether the treatment is working well.

Someone with cancer can have CEA testing regularly for several years after receiving their initial treatment.

Sample

Blood as well as other fluids such as peritoneal fluid from the abdomen.

Any preparation?

None.

Measuring levels of CEA cannot tell how big a cancer tumour is. However, people with smaller and early-stage tumours are likely to have low CEA levels, while people with more advanced tumours, or tumours that have spread to other parts of the body, are likely to have high CEA levels.

When CEA levels return to normal after treatment, 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.

Reference Intervals - comparing your results to the healthy population

Your results will be compared to reference intervals (sometimes called a normal range).

• Reference intervals are the range of results expected in healthy people.
• They are used to provide a benchmark for interpreting a patient's test results.
• When compared against them, your results may be flagged high or low if they sit outside this range.
• Some reference intervals are harmonised or standardised, which means all labs in Australia use them.
• Others are not because for these tests, labs are using different instruments and chemical processes to analyse samples.
• Always compare your lab results to the reference interval provided on the same report.

If your results are flagged as high or low this does not necessarily mean that anything is wrong. It depends on your personal situation.

Reference intervals (normal ranges) for CEA can vary between laboratories. This is because labs use different instruments and chemical processes to analyse samples. There are no harmonised reference intervals for this test.

Smoking can cause a slight increase in CEA levels (high normal levels).

The choice of tests your doctor makes will be based on your medical history and symptoms. It is important that you tell themeverything you think might help.

You play a central role in making sure your test results are accurate. Do everything you can to make sure the information you provide is correct and follow instructions closely.

Talk to your doctor about any medications you are taking. Find out if you need to fast or stop any particular foods or supplements. These may affect your results. Ask:

• Why does this test need to be done?
• Do I need to prepare (such as fast or avoid medications) for the sample collection?
• Will an abnormal result mean I need further tests?
• How could it change the course of my care?
• What will happen next, after the test?

Pathology and diagnostic imaging reports can be added to your My Health Record. You and your healthcare provider can now access your results whenever and wherever needed.

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