Oncotype DX® is a tumor profiling test that helps determine the benefit of using chemotherapy in addition to hormone therapy to treat some estrogen receptor-positive (ER-positive) breast cancers.
Every cell in your body has genes that contain the blueprints (genetic code) for your body. Similarly, every cell in a breast tumor has genes. These genes contain the blueprints for the tumor.
Tumor profiling (using gene expression profiling tools) gives information about the genes in cancer cells.
Oncotype DX is the most commonly used tumor profiling test in the U.S. and the only one used in breast cancer staging. Other tumor profiling tests (such as MammaPrint® and PAM50 (also called Prosigna®)) are available.
Oncotype DX testing
Oncotype DX tests a sample of the tumor (removed during a biopsy or surgery) for a group of 21 genes.
Along with other factors, the results of the Oncotype DX test help predict the chance of metastasis (when cancer spreads to other organs).
Breast cancer staging
Oncotype DX is part of breast cancer staging for some estrogen receptor-positive, lymph node-negative tumors. It’s the only tumor profiling test used in breast cancer staging today.
When can Oncotype DX be used?
Oncotype DX helps predict the chance of metastasis for early breast cancers that are all of the following:
- ER-positive (and will be treated with hormone therapy)
- Lymph node-negative
Oncotype DX may also be used for some postmenopausal women with invasive breast cancers that are ER-positive, HER2-negative and lymph node-positive when chemotherapy is being considered.
If Oncotype DX testing is right for you, your oncologist will review your test results with you and discuss how the Oncotype DX score may guide your treatment plan.
Oncotype DX scores
The Oncotype DX score is high
If Oncotype DX shows a person has a fairly high risk of metastasis (the Oncotype DX score is high), a more aggressive treatment plan that includes both hormone therapy and chemotherapy may be advised.
The Oncotype DX score is low
If the test shows a low risk of metastasis (the Oncotype DX score is low), the use of hormone therapy alone may be considered.
In this way, Oncotype DX may help some people with ER-positive breast cancer avoid chemotherapy and its side effects.
The Oncotype DX score is intermediate – under study
Recent findings from the TAILORx study show, for some women over 50 with an Oncotype DX score showing an intermediate risk of metastasis, treatment with hormone therapy alone may be as effective as treatment with hormone therapy and chemotherapy.
For some women 50 and younger with an Oncotype DX score showing an intermediate risk of metastasis, TAILORx showed there may be a benefit of including both hormone therapy and chemotherapy in the treatment plan.
Oncotype DX for ductal carcinoma in situ (DCIS)
The Oncotype DX test for invasive breast cancer has been modified to help predict the chance ductal carcinoma in situ (DCIS) will return as DCIS or invasive breast cancer.
It tests a sample of the DCIS tumor (removed during a biopsy or surgery) for a group of 12 genes.
This test may help identify which cases of DCIS would benefit most from radiation therapy after lumpectomy (and which women might be treated with lumpectomy alone).
This test needs further study and is not yet part of standard practice.