Oncotype DX test

This page was reviewed under our medical and editorial policy by

Daniel Liu, MD, Plastic and Reconstructive Surgeon

This page was reviewed on April 11, 2022.

The Oncotype DX® test is a type of gene expression test used widely in the United States for breast cancer. It helps doctors learn more about the chances of cancer recurring and determine whether you’d get an added benefit from chemotherapy (and, in some cases, radiation therapy) as part of your treatment plan.

The Oncotype DX test uses genetic material from cancer cells to predict how likely breast cancer is to recur after treatment and guide treatment decisions. It essentially answers the question: What are the genes in my cancer cells doing and why? This way, you can put up an informed fight.

In general, this process of gene expression profiling identifies patterns in the genetic material of cancer cells to make predictions about how they may behave. This information may lead to more personalized treatment.

Why the Oncotype DX test is done

The Oncotype DX test is a kind of risk-benefit analysis for personalized breast cancer treatment. It helps determine the treatment plan after breast cancer surgery, based on the cancer cells’ genetic makeup, while sparing you from the side effects of potentially unnecessary chemotherapy.

This test helps ascertain the likelihood that breast cancer may recur or spread after surgery.

  • If the test shows a high likelihood of recurrence, you and your care team may consider the benefits of more therapies after surgery.
  • A low chance of recurrence tells your cancer care team that adding chemotherapy to hormone therapy after surgery isn’t likely to provide an added benefit.
  • When it’s used for ductal carcinoma in situ (DCIS), or stage 0 breast cancer, it may help you and your care team decide whether or not to complete radiation therapy after surgery.

More patients today are able to bypass chemotherapy after breast cancer surgery. Forgoing chemotherapy that doesn’t provide an added benefit means avoiding the negative side effects of the treatment, such as nausea, vomiting, hair loss, fatigue and numbness in the hands or feet.

For some estrogen receptor-positive and lymph node-negative cancers, the Oncotype DX test may also be used—in addition to other test results—to determine the stage of breast cancer. So far, it’s the only gene expression test used in the breast cancer staging process.

Types of breast cancer the Oncotype DX test is used for

There are two slightly different Oncotype DX tests for breast cancer. Depending on the type and stage of your cancer, the Oncotype DX test may be helpful in planning treatment.

The Oncotype DX Breast Cancer Recurrence test is used for breast cancers that meet all of these criteria:

  • Stage 1, 2 or 3a
  • Tumor smaller than 5 cm
  • Estrogen receptor-positive (ER+)
  • HER2-negative
  • Present in three lymph nodes or less

Estrogen receptor-positive cancers have proteins that are estrogen receptors—natural human reproductive hormones—that cause cancer to grow.

HER2-negative cancers don’t have the HER2 protein that allows cancer cells to grow rapidly, and therefore wouldn’t be candidates for HER2-positive targeted drug treatments to slow the cancer’s growth.

This test helps you know the chances that the cancer may spread or recur, and whether chemotherapy after surgery would provide an added benefit.

The Oncotype DX Breast DCIS test is for DCIS. It may help you to know the chances of cancer coming back after a lumpectomy, and whether radiation therapy after surgery would be helpful based on that score. This is a newer test, and its use is still being evaluated.

If the breast cancer you have doesn’t fit the criteria for the Oncotype DX test, there may be another type of gene expression test that your cancer care team may use to guide treatment recommendations.

Because the Oncotype DX test has been developed specifically for earlier-stage breast cancers, this gene expression testing may not be used if the cancer is more advanced. Your care team may use other information they have about your cancer to determine their recommendations for treatment, whether that’s chemotherapy, hormone therapy, immunotherapy, targeted therapy or a combination of these.

How to prepare for an Oncotype DX test

You don’t need to do anything specific to prepare for an Oncotype DX test. It’s performed in a laboratory using the cancer cells from a biopsy or surgery. Ask your cancer care team when you’re likely to learn the results of the test.

When it comes to preparing for your breast biopsy or surgery, your cancer care team will tell you what you need to know. Be sure to speak up and ask questions.

What the results mean for breast cancer testing

The result from an Oncotype DX Breast Cancer Recurrence test comes back as a numerical score from 0 to 100, which represents the risk of breast cancer recurrence. Generally, the lower the score, the less likely the cancer is to recur after surgery, and the less likely chemotherapy is to provide an added benefit. A higher score means the cancer is more likely to return and there’s a higher likelihood that chemotherapy may be a beneficial part of a treatment plan.

Chemotherapy likely won’t provide added benefit with a:

  • Score of 0-15 in premenopausal women with lymph node-negative breast cancer. Hormone therapy on its own may be recommended after surgery.
  • Score of 0-25 in postmenopausal women. Hormone therapy on its own is considered after surgery.

Chemotherapy may provide some added benefit with a:

  • Score of 0-25 in premenopausal women with one to three positive lymph nodes. Though a small benefit may come from chemotherapy, it remains unclear whether that’s from the chemotherapy itself or from the ovarian suppression it causes. Patients in this category may be recommended chemotherapy and hormone therapy plus ovarian suppression, or only ovarian suppression and hormone therapy.
  • Score of 16-25 in premenopausal women with lymph node-negative breast cancer. Chemotherapy may provide a small benefit—whether due to the drugs themselves or the way they affect your ovaries. Therefore, patients with scores in this range may be recommended chemotherapy and hormone therapy plus ovarian suppression, or only ovarian suppression and hormone therapy.

Chemotherapy is likely to provide an added benefit:

  • Score of 26 and higher: In both premenopausal and postmenopausal women, a score above 26 denotes that chemotherapy is likely to provide an added benefit when paired with hormone therapy after breast cancer surgery.

Once your care team knows your recurrence score, they can make a treatment recommendation.

Results of the Oncotype DX Breast DCIS test may help you and your care team decide whether radiation therapy would be beneficial after a lumpectomy, but this newer application is still being assessed.

Other types of cancer Oncotype DX can test for

While the Oncotype DX Breast Cancer Recurrence Score is the most widely known test, there’s also an Oncotype DX Prostate test for prostate cancer.

Similar to the breast cancer test, it uses information from genes in cancer cells to make predictions about the disease. The prostate test may help determine how likely the cancer is to spread quickly.

Oncotype DX tests also exist for certain types of colon cancer and of advanced, recurrent or difficult-to-treat cancers.

Gene expression tests such as the Oncotype DX tests are a relatively new tool in the fight against cancer, and they are proving to be important catalysts in preventing unnecessary chemotherapy treatments. Additional gene expression tests for different types of cancers are currently being studied and may continue to be developed, increasing the opportunity for individualized cancer treatment in the future.

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