Different tumor markers are used at different points in the diagnosis and treatment process. The ASCO recommendations for tumor markers for breast cancer include the following:

For patients with newly diagnosed ductal carcinoma in situ (DCIS):

• DCIS means that cancer has not spread outside of the ducts in the breast. It is also called noninvasive breast cancer. No tumor marker tests for DCIS are recommended at this time.

For patients with newly diagnosed invasive breast cancer:

• ER and PR tests, to help predict response to hormone therapy after surgery
  
  
• HER2 test, to help predict response to trastuzumab and other anti-HER2 treatments and some types of chemotherapy

Once these tests are done, the cancer is classified as ER-positive (if the tumor has estrogen receptors) or ER-negative (if the tumor does NOT have estrogen receptors); PR-positive (if the tumor has progesterone receptors) or PR-negative (if the tumor does NOT have progesterone receptors); and HER2-positive (if the tumor does have HER2) or HER2-negative (if the tumor does NOT have HER2). For more information about HER2, read the ASCO Patient Guide: HER2 Testing for Breast Cancer.

For patients with node-negative breast cancer:

• uPA and PAI-1 tests, if available, to estimate the prognosis. Patients with tumors that do not have uPA and PAI-1 have a very good prognosis and may not need chemotherapy.

For patients with node-negative breast cancer that is ER-positive and/or PR-positive:

• Oncotype DX test, to identify patients who may be successfully treated with tamoxifen alone and may not need chemotherapy

For patients with metastatic breast cancer:

• ER and PR tests, to help predict response to hormone therapy
  
  
• HER2 test, to help predict response to trastuzumab and other anti-HER2 treatments
  
  
• CA 15-3 and CA 27.29, for monitoring treatment; these should be used along with the patient's health history, a physical examination, and diagnostic imaging tests, such as an x-ray, computed tomography (CT) scan, and/or magnetic resonance imaging (MRI).
  
  
• CEA, for monitoring treatment; this test should be used along with the patient's health history, a physical examination, and diagnostic imaging tests.

For patients with recurrent breast cancer:

• HER2 test, to help predict response to trastuzumab and other anti-HER2 treatments and guide the use of specific chemotherapy

Tumor marker tests may help plan and monitor treatment and guide prognosis. However, not every tumor marker is appropriate for every stage of breast cancer. The tumor markers that ASCO recommends have been shown in clinical trials to be useful for predicting response to treatment and/or finding the best treatment for patients with breast cancer. Use this guide to discuss tumor marker tests and results with your doctor.