CA 15-3 laboratory test
CA 15-3 (cancer antigen) is a protein produced by breast cells. In general, it is also produced by healthy cells, but is also increased to a greater extent in tumour cells. The protein is not the cause of cancer, it is only present in cancerous cells.
What is the purpose of the test?
The test cannot be used as a screening test because it is not sensitive enough for the early detection of breast cancer. It is primarily suitable for monitoring treatment and detecting possible recurrence of the disease. From the results of the CA 15-3 test, it can be concluded whether the patient has metastasis.
Monitoring of treatment with the help of the test usually does not start at the beginning of therapy, because in this case, there may be an increase, decrease or temporary fluctuation. After a few weeks, however, it is already reasonable.
In which cases is it recommended to perform the test?
The test is recommended in the following cases:
- If the goal is to monitor the treatment of breast cancer
- To examine recurrence of the disease after completion of treatment
What sample is needed for the test?
A blood sample taken from a vein is needed for the test.
What can the result indicate?
Decreased concentrations of CA 15-3 indicate that the body responds well to treatment. Elevated value indicates the worsening of the disease. Mild to moderate elevations of CA 15-3 may also occur in case of liver and pancreatic cancer, cirrhosis, and benign malformation of breast.
Elevations may also occur in a certain percentage of healthy individuals, so the test cannot be performed as a cancer screening.
What to do after the test?
In all cases, please consult the specialist who ordered the test with the result.
