AFP Tumour Marker Test
A blood sample taken from a vein in the arm
AFP is a protein that is normally produced by the developing foetus. However, AFP can also be produced by certain tumours and diseases of the liver. Raised concentrations of AFP are found in the majority of patients with a type of liver cancer called hepatocellular carcinoma and also in some patients with cancer of the testis.
How is it used?
AFP is used to detect certain cancers of the liver and testis. If a patient is diagnosed with one of these types of cancer, they will then undergo periodic testing for AFP initially to monitor their response to treatment, usually followed by long-term monitoring to detect any recurrence of the cancer. In one type of testicular tumour (known as a germ cell tumour), as well as helping the diagnosis, AFP & HCG measurements are also mandatory in post-treatment monitoring following guidelines that depend on the stage of the tumour and treatment.
If you have chronic hepatitis or cirrhosis of the liver, your doctor may request AFP tests to detect hepatocellular carcinoma (a type of liver cancer) which may follow in the future.
(Please note that AFP is also used in pregnant women to assess the risk of their baby having Down's syndrome – in this case it is NOT being used to test for cancer -see AFP/maternal testing).
When is it requested?
What does the test result mean?
Increased AFP can be caused by liver cancer, germ cell tumour of the testis or less commonly other cancers (for example ovary, stomach, bowel, lung, breast, lymphoma). Slightly increased levels of AFP are common in patients who have chronic hepatitis or cirrhosis and do not indicate the presence of cancer.
Is there anything else I should know?
In general, the higher the AFP result in patients with cancer, the bigger the tumour or spread if there are liver secondaries. AFP decreases when your body responds to anti-cancer therapy. If AFP does not return to normal within about one month after cancer therapy, some of the tumour may still be present.
An increase in AFP after remission suggests recurrence of the tumour. However, tumours originally producing AFP may recur without an increase in AFP concentration.
What are the risk factors for hepatocellular carcinoma?
This cancer usually occurs in people who have chronic scarring of the liver, called cirrhosis. Most commonly, this is caused by chronic infection from one of two viruses: hepatitis B and hepatitis C. Alcohol abuse also increases the risk of developing cirrhosis. Some inherited diseases, especially a disorder called haemochromatosis (in which the body absorbs and stores too much iron), which can cause cirrhosis and later hepatocellular carcinoma.
If my AFP is normal/abnormal, do I need other tests?
If you have chronic liver infection or damage, a high AFP could simply be due to the disease itself. If your AFP concentration suddenly rises, or if it is very elevated, your doctor will usually ask for a study to look at your liver, such as an ultrasound CT scan or an MRI scan. These scans can often spot liver cancers if they are present. A normal AFP result cannot be used to exclude a diagnosis of liver or testicular cancer.