What is cancer antigen 15-3 used for?

Cancer antigen 15-3 (CA 15-3) is a glycoprotein that is produced by epithelial cells in the breast. It is a well-known biomarker that is used to monitor the presence and progression of breast cancer. Here are some of the primary uses of CA 15-3:

1. Monitoring Treatment Response:

CA 15-3 levels are often used to monitor the effectiveness of treatment in patients with breast cancer. Decreasing CA 15-3 levels may indicate a positive response to treatment, such as chemotherapy or radiation therapy.

2. Early Detection and Screening:

While not recommended as a primary screening tool, CA 15-3 can be used as a complementary test in some cases. It can be useful for early detection in individuals with a high risk of breast cancer, in addition to other diagnostic methods like mammograms.

3. Prognosis:

High levels of CA 15-3 at diagnosis or during treatment may be associated with a worse prognosis and a higher risk of disease recurrence.

4. Recurrence Monitoring:

After successful treatment, CA 15-3 levels can be monitored to detect potential disease recurrence. An increase in CA 15-3 levels may indicate the return or progression of breast cancer.

5. Differential Diagnosis:

CA 15-3 can be helpful in differentiating malignant breast tumors from benign breast conditions. However, it should be used in conjunction with other diagnostic tests for accurate diagnosis.

It's important to note that CA 15-3 is not specific to breast cancer and can be elevated in other conditions as well, such as certain benign breast diseases and other types of cancer. Therefore, CA 15-3 levels should be interpreted in the context of other clinical findings and diagnostic tests by healthcare professionals.