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 to monitor their response to treatment.
The half life of AFP of five to seven days can be used to evaluate the treatment, as values which decline over a period of 25 to 30 days following treatment, indicate effective therapy.
AFP values may elevate immediately post treatment due to breakdown of tumour cells, but then decline thereafter.
Levels of AFP should be measured pre-orchiectomy (removal of the testis) to help establish a diagnosis and baseline levels for treatment and are valuable for staging and prognosis.
Other markers such as beta-hCG and LD can also be measured.
If you have chronic hepatitis or of the liver, your doctor may request AFP tests to detect hepatocellular carcinoma (HCC, a type of liver cancer).
Patients may have symptoms of liver disease already, and an AFP elevation may already be present in patients with cirrhosis, acute or chronic viral hepatitis. Any unexplained large elevation of AFP in these patients should raise concerns.
Please note that AFP is also used to in pregnant women to assess the risk of their baby having Down syndrome – in this case it is NOT being used to test for cancer (see also AFP maternal testing).
Increased AFP levels can be caused by liver cancer, germ cell tumour of the testis or less commonly other cancers (for example, stomach, bowel, lung, breast, lymphoma). Slightly increased levels of AFP are common in patients who have chronic hepatitis or . In these patients, an increase in AFP is more important than the actual numerical value of the test result.
In general, the higher the AFP level in patients with cancer, the bigger the tumour. 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.