Cancer Antigen 19-9 (CA 19-9) Test
When your doctor suspects that you have pancreatic cancer and during or following pancreatic cancer treatment.
A blood sample is obtained by inserting a needle into a vein in the arm.
No test preparation is needed
Cancer antigen 19-9 (CA 19-9) is a protein that exists on the surface of certain cells. CA 19-9 does not cause cancer; rather, it is a protein that is produced by the tumour cells, making it useful as a tumour marker to follow the course of the cancer.
CA 19-9 is elevated in most patients with advanced pancreatic cancer, but it may also be elevated in other cancers and diseases such as bowel cancer, lung cancer and gall bladder cancer, as well as in benign diseases such as gall stones, pancreatitis, cystic fibrosis, and liver disease. Because elevated levels of CA 19-9 are seen in many diseases, elevated levels do not necessary mean the presence of pancreatic cancer. Very small amounts of CA19-9 may also be found in healthy patients.
How is it used?
When is it requested?
CA 19-9 may be requested along with other tests, such as carcinoembryonic antigen (CEA), bilirubin, and/or liver function tests, when a patient has symptoms that may indicate pancreatic cancer, including abdominal pain, nausea, weight loss, and jaundice.
If CA 19-9 is initially elevated in pancreatic cancer, then it may be requested several times during cancer treatment to monitor response and, on a regular basis following treatment, to help detect recurrence of the cancer.
What does the test result mean?
Small increases in CA 19-9 levels can be detected in some healthy people, and in many benign conditions that affect the liver or pancreas can cause a temporary rise in CA 19-9.
Moderate to high levels are found in pancreatic cancer, other cancers, and in several other diseases and conditions. The highest levels of CA 19-9 are seen in a condition called excretory ductal pancreatic cancer - cancer that is found in the pancreas tissues that produce food-digesting enzymes and in the ducts that carry those enzymes into the small intestine. This tissue is where 95% of pancreatic cancers are found.
Repeated measurements of CA 19-9 may be useful during and following treatment because rising or falling levels may give your doctor important information about whether the treatment is working, whether all of the cancer was removed successfully during surgery, and whether the cancer is returning.
Is there anything else I should know?
Why is my doctor not screening me for CA 19-9?
CA 19-9 is not recommended as a screening test for people who do not have symptoms of pancreatic cancer because there are many other conditions that can cause CA 19-9 to rise. Researchers are searching for other markers that may help detect pancreatic cancer at an earlier stage and that may be more suitable for screening.
What other procedures will my doctor request with my CA 19-9?
Your doctor may request a CT scan (computed tomography), an ultrasound, an ERCP (endoscopic retrograde cholangiopancreatography, a procedure in which a small lighted tube is passed through the mouth and stomach into the small intestine), and/or a biopsy to look for cancer cells under the microscope.
What are the main risk factors for pancreatic cancer?
Doctors still do not know what causes most cases of pancreatic cancer. Identified risk factors include smoking, age (most people diagnosed with pancreatic disease are over 50 years old), gender (males are more likely to have it than females), family history, diabetes, chronic pancreatitis, and heavy occupational exposure to certain chemicals and dyes.