What are tumour marker tests?
These tests look for tumour markers, sometimes called cancer markers, in blood, urine, or body tissues. Tumour markers are substances made by cancer cells or normal cells in response to cancer in the body. Some tumour markers are specific to a type of cancer. Others can be found in various types of cancer.
Because tumor markers can also appear in certain non-cancerous conditions, tumor marker tests are generally not used to diagnose cancer or evaluate people at low risk for the disease. These tests are most often done in people who have already been diagnosed with cancer. Tumour markers can help determine if your cancer has spread, if your treatment is working, or if your cancer has come back after treatment is finished.
What are they used for?
Tumour marker tests are most often used to:
- Plan your treatment. If tumour marker levels go down, it usually means the treatment is working.
- Help find out if cancer has spread to other tissues
- Help predict the likely outcome or course of your disease
- Check to see if your cancer has come back after successful treatment
- Screen people at high risk for cancer. Risk factors can include family history and previous diagnosis of another type of cancer.
Why do I need a tumour marker test?
You may need a tumour marker test if you are currently receiving cancer treatment, have finished cancer treatment, or are at high risk of cancer due to family history or other reasons. The type of test you do will depend on your health, your medical history, and any symptoms you may have. Here are some of the most common types of tumour markers and what they are used for.
What happens during a tumour marker test?
There are different ways to evaluate tumour markers. Blood tests are the most common type of tumor marker tests. Urine tests or biopsies can also be used to look for tumor markers. A biopsy is a minor procedure that involves removing a small sample of tissue for testing.
If you are having a blood test, a healthcare professional will draw a sample of blood from a vein in your arm with a small needle. After the needle is inserted, a small amount of blood will be collected in a test tube or vial. You may feel a slight sting when the needle goes in or out. This usually takes less than five minutes.
If you are having a urine test, ask your healthcare provider for instructions on how to provide your sample.
If you are having a biopsy, a healthcare provider will remove a small piece of tissue by cutting or scraping the skin. If your provider needs to analyze tissue inside your body, he or she may use a special needle to remove the sample.
Will I have to do anything to prepare for the exam?
You usually don’t need any special preparation for a blood or urine test. If you are having a biopsy, you may need to fast (not eat or drink) for several hours before the procedure. Talk to your healthcare provider if you have any questions about preparing for your test.
Are there any risks in the test?
- There is very little risk of having a blood test. You may have mild pain or a bruise where the needle was placed, but most symptoms go away quickly.
- There is no risk for a urine test.
- If you have had a biopsy, you may have a small bruise or bleeding at the biopsy site. You may also have a little discomfort on the site for a day or two.
What do the results mean?
Depending on the type of test you have had and how it was used, your results may:
- Help diagnose the type or stage of your cancer.
- Show if your cancer treatment is working.
- Help plan future treatment.
- Show if your cancer has come back after you finish treatment.
Is there anything else I need to know about tumour marker testing?
The information provided by tumour markers may be limited because:
- Some non-cancerous conditions can cause tumor markers.
- Some people with cancer do not have tumor markers.
- Not all types of cancer have tumour markers.
Therefore, tumor markers are not often used alone to diagnose or control cancer. But they can be helpful when used in conjunction with other tests.