What exactly is CA 19-9?
CA 19-9 (Carbohydrate Antigen 19-9) is a so-called glycoprotein, i.e. a protein to which sugar residues are bound. It is excreted via the bile. This also explains why bile stasis leads to elevated CA 19-9 levels.
When is the tumor marker CA 19-9 elevated?
The CA 19-9 threshold value is about 37 U/ml (= units per milliliter). However, the threshold value can vary with different measurement methods. Exceeding the limit value is mainly found in the following cancers:
- Pancreatic cancer (pancreatic carcinoma)
- Stomach cancer (gastric carcinoma)
- Cancer of the large intestine (colon carcinoma)
- rectal cancer (rectal carcinoma)
- Cancer of the liver (hepatocellular carcinoma)
- Bile duct cancer (bile duct carcinoma)
- Inflammation of the pancreas (pancreatitis)
- Inflammation of the gallbladder (cholecystitis)
- Inflammation of the bile ducts
- Gallstones (cholelithiasis or choledocholithiasis)
- Chronic inflammation of the liver (chronic hepatitis)
- Cirrhosis of the liver
- Cystic fibrosis (cystic fibrosis)
How useful is the determination of the tumor marker?
In the case of pancreatic cancer (pancreatic carcinoma), the tumor marker has a high significance: even with small tumors (< 3 cm in diameter), about half of all patients show an elevated CA 19-9 value. In the case of larger tumors, this figure is as high as 90 percent of all patients.
In the case of cancers of the bile ducts, stomach, and colon and rectum, however, the test is not quite as sensitive. As with most tumor markers, however, CA 19-9 is not suitable as the sole screening test for cancer. However, it is useful to determine the values during the course of the disease, for example to monitor the success of a therapy.
