Tumor marker refers to a substance that is present in an individual’s urine, blood or the tumor itself. Tumor marker is secreted either by the body or by the tumor in the presence of cancer. You may be recommended to have tumor markers tested at various stages of cancer to aid in the diagnosis and treatment. In combination with other medical tests, a test done to measure tumor marker is quite helpful in providing useful information regarding the cancer and its treatment. For those who are concerned, it helps to know what these tumor markers mean and which tumor marker test to choose for a particular breast cancer.
Tumor markers for breast cancer are used in the following ways:
The common tumor markers used for breast cancer are: ER and PR, HER2, CA 15-3, CA 27.29 and CEA, uPA, PAI-1 and oncotype DX.
ER and/or PR positive breast cancer cells require estrogen and/or progesterone for their growth. ER and PR testing is done to determine whether the cancer requires hormone therapy such as tamoxifen (Nolvadex) for treatment.
This is a protein that is present in large quantities in almost 20-25% of breast cancer cases. To stop the growth of cancer cells anti-HER2 treatment is given which blocks HER2. HER2 tests help the physician to determine whether the cancer requires anti-HER2 treatment such as trastuzumab (Herceptin) or not.
These are tumor markers that are present in almost 50-90% of patients suffering from metastatic breast cancer. However, high levels may indicate other condition apart from cancer. These tests are also monitored to determine an early recurrence after initial treatment of the primary tumor. It is also done to determine the success of cancer treatment.
These tumor markers are present in high amounts in aggressive forms of cancer or cancers which grow very fast. These tests require specific methods to store and save the tissue for testing and are not as common as other tumor marker tests. Test for these tumor markers is done to determine whether chemotherapy is required after surgery in patients having node-negative (meaning having no cancer found in lymph nodes) breast cancer.
This test is the measurement of multiple genes at one time to determine the risk of recurrence of breast cancer in patients who have early-stage, ER positive and node-negative breast cancer. Patients who have a low recurrence score usually require treatment with only hormone therapy and they can avoid chemotherapy.
Tests for tumor markers help in both planning and monitoring cancer treatment and in determining the prognosis of cancer. The tumor markers mentioned above are helpful in predicting the response to particular therapy and/or also in finding the best treatment for your cancer.
You should ask your doctor the following questions to know more about tumor markers:
Type of Breast Cancer | Recommended Tumor Marker Tests |
---|---|
Newly diagnosed ductal carcinoma in situ (DCIS) |
No tumor marker tests are recommended as DCIS implies that the cancer is confined to the ducts of the breast and is non-invasive in nature. |
Newly diagnosed invasive breast cancer |
|
Node-negative breast cancer |
uPA and PAI-1 tests to determine the prognosis of cancer. Patients with negative uPA and PAI-1 have excellent prognosis and may not require chemotherapy. |
Node-negative breast cancer that is ER positive and/or PR positive |
Oncotype DX test to identify the patients who will require only tamoxifen and can avoid chemotherapy. |
Metastatic breast cancer |
|
Recurrent breast cancer |
HER2 test to determine the response to trastuzumab and other anti-HER2 treatments and indicate which specific chemotherapy need to be used. |