Cancer is not diagnosed by blood tests alone. As well as finding out how well organs in the body are working, you may be tested for a cancer marker. Markers are chemical substances that can show up in the bloodstream in some types of cancer.
There are two markers that some pancreatic cancers may produce – CEA and CA19-9.
Serum CA 19-9 is more commonly used and is considered to be elevated when its value is greater than 37 U/mL
What does the CA 19-9 test measure?
The CA 19-9 is a simple blood test that measures the level of antigens – substances that cause the immune system to make a specific immune response – in the blood serum of a person with pancreatic cancer. CA 19-9 antigens are the substances released by pancreatic tumor cells.
The normal range of CA 19-9 in the blood of a healthy individual is 0-37 U/mL (Units per milliliter).
CA 19-9 associated antigen levels are elevated in the blood of many patients with pancreatic cancer.
NOT EVERY PATIENT WITH PANCREATIC CANCER WILL HAVE ELEVATED CA19-9
There are also some non-cancerous conditions that cause a high level of CA19-9 which is why it is not particularly useful as a diagnostic test for pancreatic cancer.
When is the CA 19-9 test used?
After the diagnosis of pancreatic cancer is confirmed and if the individual’s CA 19-9 level was elevatedbefore treatment, the CA 19-9 test can be used as a prognostic factor (to see how effective treatments are for example).
What do the results of a CA 19-9 test mean?
These are generalisations only and you should talk to your doctor(s) about what your levels of CA 19-9 mean for you:
- If CA 19-9 values increase, then progression (growth) of the tumour is considered.
- If CA 19-9 values stay the same, then the disease is stable.
- If CA 19-9 values decrease, then a response to treatment is indicated.
- If CA 19-9 levels decrease after treatment for pancreatic cancer then rise later this may suggest tumour recurrence.
How is the CA 19-9 test performed?
A blood sample is taken from the patient and then sent to a laboratory for testing to determine the level of CA 19-9 present in the blood.
How often will I have a CA 19-9?
Your oncologist/surgeon will determine how frequently the CA 19-9 tests should be performed.
- If patients are undergoing chemotherapy, the CA 19-9 test may be repeated after each cycle of treatment is completed.
- In a patient who is not currently receiving treatment, the CA 19-9 test may be used periodically to determine if that patient should resume treatment or undergo additional testing.
- People who had their tumors surgically removed might have periodic CA 19-9 tests as part of their follow-up care.
Can conditions other than pancreatic cancer cause an elevated CA 19-9?
Yes. While a high CA 19-9 is most commonly associated with pancreatic cancer, high levels can also be found in patients with other cancers such as colorectal, lung, and gall bladder.
High CA 19-9 levels can also be caused by non-cancerous conditions such as gall stones, pancreatitis, cystic fibrosis, and liver disease.
Some patients undergoing radiotherapy may have higher CA 19-9 levels as the dying pancreatic cancer cells will release CA19-9. This can distort the results of a CA 19-9 test so it is not usually performed while the patient receives radiotherapy treatment.
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