Oncotype DX® is a tumor profiling test. It 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 cancer.
Tumor profiling (using gene expression profiling tools) gives information about the genes in cancer cells. You may also hear the terms genomic testing and molecular profiling.
Oncotype DX is the most common tumor profiling test in the U.S. Other tumor profiling tests, such as MammaPrint® and PAM50 (also called Prosigna®), are available. Oncotype DX is the only one used in breast cancer staging.
Oncotype DX testing
Oncotype DX tests a sample of the tumor (removed during a biopsy or surgery) for a group of 21 genes.
The results of the Oncotype DX test help predict the chance of metastasis (when cancer spreads to other organs) and the likelihood of benefit of getting chemotherapy in addition to hormone therapy.
Breast cancer staging
Oncotype DX can be included as 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.
If Oncotype DX testing is done, the results are used in combination with other factors to determine stage.
Learn more about breast cancer staging.
When can Oncotype DX be used?
Oncotype DX helps predict the chance of metastasis and the likelihood of benefit from chemotherapy for early breast cancers that are all of the following [16,34-36]:
- Tumor size larger than 5 cm
- ER-positive (and will be treated with hormone therapy)
- Lymph node-negative
Although not routine, 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 [34-36].
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 31 or higher
If Oncotype DX shows a fairly high risk of metastasis (the Oncotype DX score is 31 or higher), a more aggressive treatment plan that includes both hormone therapy and chemotherapy is usually recommended [16,34-36].
The Oncotype DX score is 26-30
If the Oncotype DX score is 26-30, a treatment plan that includes chemotherapy (in addition to hormone therapy) may or may not be advised .
Study findings show the benefit of chemotherapy varies by age for women with Oncotype DX scores that show neither a high risk nor a low risk of metastasis .
In younger women, chemotherapy can shut down the ovaries and stop them from producing estrogen. (This causes menstrual periods to become irregular or stop altogether.) Younger women appear to get a treatment benefit from the ovarian suppression caused by the chemotherapy .
The Oncotype DX score is less than 26
If the test shows a low risk of metastasis (the Oncotype DX score is less than 26), the use of hormone therapy alone may be considered [16,34-36]. In this way, Oncotype DX may help some people with ER-positive breast cancer avoid chemotherapy and its side effects.
For women 50 and younger with an Oncotype DX score of 16-25, the TAILORx study showed there may be a benefit of including both hormone therapy and chemotherapy in the treatment plan .
Oncotype for ductal carcinoma in situ (DCIS) test
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 isn’t part of standard care.