CA 15-3

What is the purpose of the CA 15-3 test?

CA 15-3 is a tumor marker test primarily used to monitor the treatment response and disease progression in breast cancer patients. While it is not used as a standalone diagnostic tool for breast cancer, elevated levels can indicate recurrence or metastasis. It's also used to monitor other cancers and certain non-cancerous conditions.


When is this test recommended?

Doctors usually recommend the CA 15-3 test for patients with a confirmed diagnosis of breast cancer, particularly during or after treatment, to assess how well therapy is working. It may also be used during follow-up visits to detect early signs of cancer recurrence. Occasionally, it is used in evaluating symptoms that may be linked to metastasis.


How is the test conducted?

 The CA 15-3 test is a simple blood test. A sample is drawn and analyzed using immunoassays to measure the concentration of the CA 15-3 antigen in the blood. The procedure is minimally invasive and results are typically available within a few days.


What do the results indicate?

Elevated CA 15-3 levels may indicate the presence of active breast cancer, particularly metastatic disease. However, levels can also rise due to other cancers (e.g., ovarian or lung) or non-malignant conditions like liver disease. A declining CA 15-3 level during treatment usually suggests a favorable response, while rising levels may signal disease progression.


What should be done after getting the results?

Results should be interpreted by a healthcare provider alongside imaging studies and clinical findings. If CA 15-3 levels are elevated or rising, further diagnostic tests such as PET scans or biopsies may be ordered. If levels are stable or decreasing, it typically means treatment is effective, and ongoing monitoring will continue as per the cancer management plan.