Oncotype DX Test
More than half of women in the U.S. who are diagnosed with breast cancer have estrogen receptor-positive (ER+), lymph node-negative cancer. This means that the cancer’s growth is fueled by the hormone estrogen, and it can be treated with hormonal therapies that block or lower estrogen. It also means that the cancer has not spread from the original tumor site to the lymph nodes. Negative lymph nodes are a good sign: if there is no evidence of cancer cells in the lymph nodes, then the cancer most likely is limited to the breast.
If you find yourself in this group of women, you may wonder whether or not you really need chemotherapy in addition to hormonal therapy. Both chemotherapy and hormonal therapy are systemic treatments (medications that travel throughout the entire body) given to help reduce the risk that the cancer will return or spread. Studies have shown that chemotherapy offers added benefit for only a fraction of women with early-stage (stage I or II), node-negative, ER+ cancer who take hormonal therapy. That’s because only a small number of these early cancers pose a high risk of recurring or spreading outside the breast.
Now, a new test called Oncotype DX is available to help you and your doctor determine whether or not the cancer is:
- likely to recur
- likely to benefit from chemotherapy
The results of this test, combined with other features of the cancer, can help you make a more informed decision about whether or not to have chemotherapy. Below, you can read more about the following topics:
- Who is eligible for the Oncotype DX test?
- How does Oncotype DX work?
- Interpreting the results
- Insurance coverage and financial assistance
Who is eligible for the Oncotype DX test?
Most women with early-stage (stage I or II), estrogen receptor-positive (ER+) breast cancer that has not spread to the lymph nodes are considered to be at low risk for recurrence. After surgery, hormonal therapies such as tamoxifen or an aromatase inhibitor are prescribed to reduce the risk that the cancer will come back in the future. Whether or not chemotherapy is necessary as well has been an area of uncertainty for women and their doctors.
Even though all signs suggest that these cancers are low risk, a small number of them will eventually recur — either in the breast or surrounding area, or somewhere else in the body. Identifying exactly which early-stage, ER+, node-negative breast cancers pose a risk of recurrence has proven challenging. Therefore, some women and their doctors have chosen to go ahead with chemotherapy anyway, despite its side effects and impact on quality of life. Other women have chosen not to have chemotherapy, even though there is a small chance they could be in the group that will experience recurrence.
Oncotype DX is a test that can help you and your doctor make a more informed decision about whether or not you need chemotherapy. Oncotype DX is known as a genomic assay—it 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.
How does Oncotype DX work?
The Oncotype DX test uses a sample of your breast tumor tissue to analyze the activity of 21 different genes. Genes control the behavior and activities of all cells, including cancer cells. When cells are behaving abnormally, this can often be traced back to unusual activity by certain genes.
Looking at this set of 21 genes can provide specific information on:
- the likelihood that your breast cancer will return
- whether you are likely to benefit from commonly used chemotherapy regimens
So, Oncotype DX 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 treatment. Studies have shown that Oncotype DX is useful for both purposes. The American Society for Clinical Oncology and the National Comprehensive Cancer Network now include the Oncotype DX test in their treatment guidelines for early breast cancer.
If you are diagnosed with ER+, node-negative, early-stage breast cancer, you can talk to your doctor about having the Oncotype DX test. (Some early research suggests the test also may be informative for postmenopausal women with stage II-III breast cancer that has spread to the lymph nodes. Again, talk to your doctor.) The pathology lab that originally preserved and examined your tumor tissue would need to send out samples to Genomic Health, the company that performs the test. The test involves extracting RNA (part of the genomic makeup of the cells) from the tumor sample and analyzing it to determine the level of activity — or expression — of each of 21 genes.
Based on this analysis, Oncotype DX assigns the breast cancer a Recurrence Score. This score is a number between 0 and 100 that corresponds to a specific likelihood of experiencing breast cancer recurrence within 10 years of your initial diagnosis. The lower your score, the less likely the cancer is to recur. The higher the score, the more likely the cancer is to recur.
Interpreting the results
When the Oncotype DX test is complete, your doctor will receive a report that includes:
- your Recurrence Score
- information about the average 10-year recurrence rate for women in your scoring range
You and your doctor can use the following ranges to interpret your results:
- Recurrence Score lower than 18: This suggests you have a low risk of recurrence. The benefit of chemotherapy is likely to be small and will not outweigh the risks of side effects.
- Recurrence Score between 18 and 31: This score suggests you have an “intermediate” risk of recurrence. It’s unclear whether the benefits of chemotherapy outweigh the risks of side effects.
- Recurrence Score greater than 31: You have a high risk of recurrence, and the benefits of chemotherapy are likely to be greater than the risks of side effects.
You and your doctor will consider your 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 wish to have chemotherapy in addition to hormonal therapy.
Like other women, you may find that a low Recurrence Score gives you the peace of mind to forego chemotherapy. A high Recurrence Score, on the other hand, may sway you towards having chemotherapy. If you are in the intermediate group, you and your doctor will need to work together closely to determine what is right for your individual situation.
Researchers continue to investigate the best ways to use the Oncotype DX test results. A large clinical trial called TAILORx (Trial Assigning Individualized Options for Treatment), a collaboration between Genomic Health and the National Cancer Institute, is enrolling over 10,000 women at 900 sites in the United States and Canada. The study is designed to find out if women with scores in the 11 to 25 score range — from low to intermediate risk — benefit from chemotherapy in addition to hormonal therapy, or whether hormonal therapy alone is just as beneficial.
For more information, or to see if the TAILORx trial is available in your area, visit the NCI Web page on the trial.
Insurance coverage and financial assistance
The Medicare program and several other insurance companies cover the Oncotype DX test when it is considered to be medically necessary. However, because the test is relatively new, not all insurance carriers have a policy in place yet. Talk to your doctor: he or she may be able to work with your insurance company to increase the likelihood of coverage. If you have a low Recurrence Score and you and your doctor decide you do not need to have chemotherapy, 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. The Oncotype DX test costs about $3,500.
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.
For insurance- and payment-related questions, call 1-866-ONCOTYPE (1-888-662-6897) or visit the Genomic Health Web site.