What exactly is CA 15-3?
CA 15-3 is a so-called glycoprotein, i.e. it consists of sugar and protein components. It is formed in the mucosal cells, which then release it into the blood. Only small amounts of the glycoprotein are found in the blood serum of healthy patients.
Normal value CA 15-3
In healthy individuals, theCA 15-3value is below 31 enzyme units per milliliter (< 31 U/ml).
When is the tumor marker CA 15-3 elevated?
As the name tumor marker suggests, CA 15-3 increases in certain cancers. These include breast cancer (mammary carcinoma) and ovarian cancer (ovarian carcinoma) in particular, but also malignant tumors of the pancreas, liver, stomach and bronchi.
Apart from these, elevated CA 15-3 levels are also found in some benign diseases, for example:
- liver inflammation (hepatitis)
- Liver cirrhosis
- Kidney failure
- diseases of the bronchial tubes
- benign changes in the mammary gland (for example fibroadenoma or mastopathy)
CA 15-3 has a sensitivity of only 5 to 30 percent in early breast cancer. This means that the tumor marker can only be used to actually detect the malignant tumor in 5 to 30 out of 100 women with breast cancer. However, the level of the tumor marker is related to the size and stage of the tumor and thus enables a more accurate assessment.
Furthermore, the sensitivity increases if the physician additionally determines the tumor marker CEA and assesses the values in their synopsis. The determination of CA 15-3 is only really useful as a follow-up test when the cancer is known. The oncologist can use it, for example, to assess the success of a therapy. However, in order to be able to reliably say how the values will develop, it is essential that the same measurement procedure is used in the laboratory when CA 15-3 is determined again. Otherwise, the values cannot be compared.
