Tumor genomic assays (or tests) analyze a sample of a cancer tumor to see how active certain genes are. The activity level of these genes affects the behavior of the cancer, including how likely it is to grow and spread. Genomic tests are used to help make decisions about whether more treatments after surgery would be beneficial.
While their names sound similar, genomic testing and genetic testing are very different.
Genetic testing is done on a sample of your blood, saliva, or other tissue and can tell you if you have an abnormal change (also called a mutation) in a gene that is linked to a higher risk of breast cancer. See the Genetic Testing pages for more information.
There are several tests used to analyze the genes in a breast cancer to help predict whether the breast cancer will come back (recurrence). All of the tests can be done on a sample of preserved tissue that was removed from the breast during the original biopsy or surgery.
The differences between the tests are explained below. To learn about each in more detail, click the link for each test.
- The Breast Cancer Index test analyzes the activity of seven genes to help predict the risk of node-negative, hormone-receptor-positive breast cancer coming back 5 to 10 years after diagnosis. The test can help women and their doctors decide if extending hormonal therapy 5 more years (for a total of 10 years of hormonal therapy) would be beneficial.
The Breast Cancer Index reports two scores: how likely the cancer is to recur 5 to 10 years after diagnosis and how likely a woman is to benefit from taking hormonal therapy for a total of 10 years.
The Breast Cancer Index test is not approved by the FDA but may be covered by some insurance companies.
- The EndoPredict test is used to predict the risk of distant recurrence of early-stage, hormone-receptor-positive, HER2-negative breast cancer that is either node-negative or has up to three positive lymph nodes.
The EndoPredict test analyzes 12 genes to see how active they are, and then combines that risk score with the cancer’s size and nodal status to calculate an EPclin Score that categorizes the cancer as having either a high risk or low risk of distant recurrence. The EndoPredict test is sold as a kit to local pathology labs, rather than done as a centralized laboratory service like some of the other genomic tests. The EndoPredict test is not approved by the U.S. Food and Drug Administration (FDA) and is only available in Europe.
- The MammaPrint test analyzes 70 genes to see how active they are and then calculates either a high-risk or a low-risk recurrence score.
Research suggests the MammaPrint test eventually may be widely used to make treatment decisions based on the recurrence risk of early-stage, hormone-receptor-positive or hormone-receptor-negative disease.
- The Oncotype DX test is used to estimate a woman’s risk of recurrence of early-stage, hormone-receptor-positive breast cancer, as well as how likely she is to benefit from chemotherapy after breast cancer surgery.
The Oncotype DX DCIS test analyzes the activity of 12 genes and then estimates a woman’s recurrence risk of DCIS (ductal carcinoma in situ) and/or the risk of a new invasive cancer developing in the same breast, as well as how likely she is to benefit from radiation therapy after DCIS surgery.
The Oncotype DX test analyzes the activity of 21 genes and then calculates a recurrence score number between 0 and 100; the higher the score, the greater the risk of recurrence of an invasive breast cancer.
Of the genomic tests used on breast cancer, the Oncotype DX test has the most thorough data supporting its use to make treatment decisions. Because of this strong research, the Oncotype DX test is the most common test used in the United States to make treatment decisions.
- The Prosigna Breast Cancer Prognostic Gene Signature Assay analyzes the activity of 58 genes and calculates a risk of recurrence score (low, intermediate, or high).
Research suggests the Prosigna assay eventually may be used more frequently to make treatment decisions based on the risk of distant recurrence (cancer coming back in a part of the body away from the breast) within 10 years of diagnosis of early-stage, hormone-receptor positive disease with up to three positive lymph nodes after 5 years of hormonal therapy treatment in postmenopausal women.
Whichever test you have, you and your doctor will consider your scores in combination with the other information in your pathology report, such as:
- size and grade of the cancer
- hormone receptor protein levels
- whether cancer cells were found in nearby lymph nodes
to come up with a treatment plan for you.
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