The Oncotype DX test is a genomic test that analyzes the activity of a group of genes that can affect how a cancer is likely to behave and respond to treatment. The Oncotype DX is used in two ways:
- To help doctors figure out a woman’s risk of early-stage, estrogen-receptor-positive breast cancer coming back (recurrence), as well as how likely she is to benefit from chemotherapy after breast cancer surgery.
- To help doctors figure out a woman’s risk of DCIS (ductal carcinoma in situ) coming back (recurrence) 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 results of the Oncotype DX test, combined with other features of the cancer, can help you make a more informed decision about whether or not to have chemotherapy to treat early-stage hormone-receptor-positive breast cancer or radiation therapy to treat DCIS.
Who is eligible for the Oncotype DX test?
You may be a candidate for the Oncotype DX test if:
- you’ve recently been diagnosed with stage I or II invasive breast cancer
- the cancer is estrogen-receptor-positive
- there is no cancer in your lymph nodes (lymph node-negative breast cancer)
- you and your doctor are making decisions about chemotherapy.
Most early-stage (stage I or II), estrogen-receptor-positive breast cancers that haven’t spread to the lymph nodes are considered to be at low risk for recurrence. After surgery, hormonal therapies such as an aromatase inhibitor or tamoxifen are prescribed to reduce the risk that the cancer will come back in the future. Whether or not chemotherapy is also necessary has been an area of uncertainty for patients and their doctors.
If you’ve been diagnosed with early-stage, estrogen-receptor-positive breast cancer, the Oncotype DX test can help you and your doctor make a more informed decision about whether or not you need chemotherapy. (Some research also suggests the test may help postmenopausal women with estrogen-receptor-positive breast cancer that has spread to the lymph nodes make chemotherapy decisions. Talk to your doctor if you are in this group.)
You also may be a candidate for the Oncotype DX test if:
- you’ve recently been diagnosed with DCIS
- you’re having lumpectomy to remove the DCIS
DCIS is the most common form of non-invasive breast cancer. DCIS usually is treated by surgically removing the cancer (lumpectomy in most cases). After surgery, hormonal therapy may be recommended if the DCIS is hormone-receptor-positive. Radiation therapy may be recommended for some women. Doctors aren’t always sure which women will benefit from radiation therapy.
If you’ve been diagnosed with DCIS, the Oncotype DX test can help you and your doctor make a more informed decision about whether or not you need radiation therapy.
How does Oncotype DX work?
The Oncotype DX genomic test looks at groups of genes and how active they are, which can influence how a cancer is likely to grow and respond to treatment. A genomic test is different from a genetic test. A genetic test looks for mutations (unusual changes) in genes that are inherited, or passed from one generation to the next.
The Oncotype DX test uses a sample of breast cancer tissue to analyze the activity of 21 genes. Genes control the behavior and activities of all cells, including cancer cells. When cells are behaving abnormally, it often can be traced back to unusual activity by certain genes.
Looking at these 21 genes can provide specific information on:
- the likelihood that the breast cancer will return
- whether you’re likely to benefit from chemotherapy if you’re being treated for early-stage invasive breast cancer
- whether you’re likely to benefit from radiation therapy if you’re being treated for DCIS
So, the Oncotype DX test is both a prognostic test, since it provides more information about how likely (or unlikely) the breast cancer is to come back, and a predictive test, since it predicts the likelihood of benefit from chemotherapy or radiation therapy treatment. Studies have shown that Oncotype DX is useful for both purposes. The American Society for Clinical Oncology (ASCO) and the National Comprehensive Cancer Network (NCCN) now include the Oncotype DX test in their treatment guidelines for early-stage breast cancer. Because the Oncotype DX test for DCIS is relatively new, it’s not yet included in the ASCO or NCCN DCIS treatment guidelines.
Oncotype DX test results assign a Recurrence Score — a number between 0 and 100 — to the early-stage breast cancer or DCIS. You and your doctor can use the following ranges to interpret your results:
- Recurrence Score lower than 18: The cancer or DCIS has a low risk of recurrence. The benefit of chemotherapy for early-stage breast cancer or radiation therapy for DCIS is likely to be small and will not outweigh the risks of side effects.
- Recurrence Score between 18 and 31: The cancer or DCIS has an intermediate risk of recurrence. It’s unclear whether the benefits of chemotherapy for early-stage breast cancer or radiation therapy for DCIS outweigh the risks of side effects.
- Recurrence Score greater than 31: The cancer or DCIS has a high risk of recurrence, and the benefits of chemotherapy for early-stage breast cancer or radiation therapy for DCIS are likely to be greater than the risks of side effects.
You and your doctor will consider the Recurrence Score in combination with other factors, such as the size and grade of the cancer, the number of hormone receptors the cancer cells have (many versus few), and your age. Together you can make a decision about whether or not you should have chemotherapy or radiation therapy.
How is Oncotype DX different from the MammaPrint test and the Mammostrat test?
You may have heard about two other tests that analyze breast cancer genes to predict recurrence:
- the MammaPrint test
- the Mammostrat test
While all three tests are somewhat similar, there are differences:
- 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 test also is used to estimate 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.
- The MammaPrint test is used to estimate a woman’s recurrence risk for early-stage breast cancer. The breast cancer can be hormone-receptor-positive or hormone-receptor-negative. 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. MammaPrint results can help a woman and her doctor make a more informed decision about whether to use chemotherapy to reduce recurrence risk.
- The Mammostrat test is used to estimate a woman’s risk of recurrence of early-stage, hormone-receptor-positive breast cancer. The Mammostrat test measures the levels of five genes in breast cancer cells. These measurements are used to calculate a risk index score. The higher the risk index, the more likely the cancer is to come back. Women are assigned to a risk category (high, moderate, or low) based on their risk index score.
Insurance coverage and financial assistance
The Medicare program and several other major insurance companies have agreed to cover the Oncotype DX test. According to Genomic Health, about 90% of insured people in the U.S. are members of a plan that covers the test. If you discover that your plan does not cover the Oncotype DX test, talk to your doctor: he or she may be able to work with your insurance company to get coverage. If you have a low Recurrence Score and you and your doctor decide you do not need to have chemotherapy or radiation, your insurance company can save much more than the cost of the test.
Genomic Health also has started the Genomic Access Program to assist you with verifying insurance coverage and obtaining reimbursement. If you do not have or cannot secure insurance coverage, the Genomic Access Program still may be able to help. Various forms of financial assistance and payment plans are available for people facing financial hardships or those who are uninsured or underinsured. The Oncotype DX test costs about $4,000. For insurance- and payment-related questions, call 1-866-ONCOTYPE (1-866-662-6897).
Dr. Maria Simbra
for chemotherapy, I had a hard time wrapping my mind around that.”
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