Tumor Markers for Breast Cancer

Tumor markers are made by cancer cells or by other cells in your body in response to cancer. Tumor markers for breast cancer can be found in the blood and are checked using a blood test. Having a high level of a tumor marker suggests that cancer is in the body, but by itself, a high tumor marker level is not enough to be sure that cancer is present.

Tumor markers may be used with other tests to help diagnose cancer. Some markers can help figure out your prognosis and choose the best treatment. However, in breast cancer, tumor markers are most often used to test your response to cancer treatment or to watch for recurrence (the cancer coming back). A decrease in the level of a tumor marker may mean that the cancer is responding to treatment. If there is no change or the tumor marker increases, this may mean that the treatment is not working or that the cancer has returned. These results must be reviewed in combination with radiology tests, physical exam, and the increase or decrease in any symptoms you may be having. The tumor marker level alone is not enough for a clear picture of your cancer.

There are some limits to the use of tumor markers. There are non-cancerous problems that can cause tumor markers to be high. Not everyone with breast cancer will have an increase in a tumor marker. Your care team will recommend testing for tumor markers only if you need them.

Tumor Marker Blood Tests for Breast Cancer

• CA 15-3.
• CA 27.29.
• CA 125.
• Carcinoembryonic antigen (CEA).

Further Reading

OncoLink Patient Guide to Tumor Markers

The American Society of Clinical Oncology (ASCO) has clinical practice guidelines on a variety of topics, including tumor markers for breast cancer. These guidelines called What to Know: ASCO's Guidelines, are available on the ASCO website, www.cancer.net.

Read more about breast cancer at OncoLink.org