Dear OncoLink "Ask the Experts,"
More than 4 years after an operation for gastric cancer my CA19-9 marker has gone up. Testing does not reveal any clue as to why this has happened. What is CA19-9 and why might this be happening?
Li Liu, MD, Editorial Assistant for OncoLink, responds:
Thank you for your interest and question.
Carbohydrate antigen 19-9 (CA19-9) is a glycoprotein of normal cells. It has been used in monitoring of malignancies of the gastrointestinal tract. Recently it was used for possible expression in gynecologic malignancies along with other tumor markers, such as carcinoembryonic antigen (CEA) and CA-125. However, CA19-9 has a relatively low sensitivity and also is non-specific. For male patients, there was one case report of elevated serum CA19-9 associated with prostate cancer. In this case, serum PSA would be very helpful.
Other non-malignant diseases have also been reported to be associated with high level serum CA19-9. These include: interstitial pneumonia; interstitial pulmonary fibrosis; mediastinal bronchogenic cyst; splenic cyst; and auto-immune hepatitis.
Some oncologists believe that one of the general principles of cancer treatment is to treat the cancer not number.
You should discuss your treatment with your oncologist.