An elevated CA 19-9 level is most frequently associated with pancreatic cancer, but it can also be raised by other cancers and certain non-cancerous conditions.
Here's a breakdown of the causes:
Cancer-Related Causes
- Pancreatic Cancer: This is the most common malignant cause of elevated CA 19-9.
- Other Cancers: CA 19-9 can also be elevated in cancers of the:
- Colon and rectum
- Stomach
- Esophagus
- Liver
- Gallbladder and bile ducts
- Ovary
Non-Cancerous (Benign) Causes
Elevated CA 19-9 levels aren't always indicative of cancer. Several benign conditions can also cause an increase, including:
- Pancreatitis: Both acute and chronic inflammation of the pancreas.
- Biliary Tract Diseases: Conditions affecting the gallbladder and bile ducts, such as:
- Cholangitis (inflammation of the bile ducts)
- Cholecystitis (inflammation of the gallbladder)
- Gallstones
- Liver Diseases: Conditions affecting the liver, such as cirrhosis or hepatitis.
- Cystic Fibrosis: This genetic disorder can cause increased CA 19-9, even in the absence of pancreatic cancer.
- Other conditions: Less common causes can include thyroid disease, kidney disease, and some inflammatory conditions.
Important Considerations:
- CA 19-9 is not a reliable screening test for cancer in the general population because many benign conditions can elevate its level.
- CA 19-9 is most useful in monitoring the treatment response in patients already diagnosed with certain cancers (particularly pancreatic cancer). A decrease in CA 19-9 often indicates that the treatment is effective.
- Some people lack the Lewis antigen, which is required for CA 19-9 production. In these individuals, CA 19-9 levels will always be low, even if cancer is present. This means CA 19-9 is not useful as a tumor marker in these individuals.
In summary, while pancreatic cancer is a frequent cause of elevated CA 19-9, a range of other cancerous and non-cancerous conditions can also lead to increased levels of this marker. It's crucial to interpret CA 19-9 levels in the context of a patient's overall clinical picture, including their medical history, physical exam findings, and other diagnostic test results.
