The Oncotype DX test is a genomic test that analyzes the activity of 21 genes that can affect how a cancer is likely to behave and respond to treatment. The Oncotype DX test 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 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
A study has found that the Oncotype DX test to assess the recurrence risk of early-stage, estrogen-receptor-positive breast cancer was quickly adopted after it was approved for Medicare coverage and that the test is being given to appropriate women no matter how much money they make, where they live, or other demographic factors.
The study was published online on March 5, 2015 by JAMA Oncology. Read “Initial Trends in the Use of the 21-Gene Recurrence Score Assay for Patients With Breast Cancer in the Medicare Population, 2005-2009.”
Because using the Oncotype DX test to evaluate DCIS started later, this study only looked at using the Oncotype DX test to assess invasive breast cancer.
Oncotype DX test results assign a recurrence score -- a number between 0 and 100 -- to the early-stage breast cancer:
- Recurrence score lower than 18: The cancer has 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 of 18 up to and including 30: The cancer has an intermediate risk of recurrence. It’s unclear whether the benefits of chemotherapy outweigh the risks of side effects.
- Recurrence score greater than or equal to 31: The cancer has a high risk of recurrence and the benefits of chemotherapy are likely to be greater than the risks of side effects.
While the Oncotype DX DCIS test uses the same range for recurrence scores -- 0 to 100 -- the scores are interpreted differently.
In this study, the researchers looked at records in SEER databases and found 70,802 women who were 66 or older when diagnosed with early-stage, hormone-receptor-positive breast cancer between 2005 and 2009. The women all had Medicare insurance coverage and were good candidates for the Oncotype DX test.
SEER databases are large registries of cancer cases from sources throughout the United States maintained by the National Institutes of Health.
Overall, the researchers found that use of the Oncotype DX test went up from 2005 to 2009:
- 1.1% of the women had Oncotype DX testing in 2005
- 10.1% of the women had Oncotype DX testing in 2009
Most of the tests were given to women diagnosed with cancers classified as having an intermediate risk of recurrence based on the characteristics of the cancer:
- no cancer cells in the lymph nodes
- cancer larger than 1 cm
In other words, doctors thought the cancers had an intermediate risk of recurrence before the Oncotype DX test was done. This makes sense because the Oncotype DX test is recommended for women with an intermediate risk of recurrence.
Women were more likely to have an Oncotype DX test if they:
- were younger
- had fewer other health conditions
- were diagnosed with higher grade cancer
- were married
The following factors had no effect on whether a woman was likely to get an Oncotype DX test:
- the region where a woman lived
- being black
- living in an urban area
When the researchers looked specifically at women in the study who were younger than 70 who were diagnosed with breast cancer considered to have an intermediate risk of recurrence, they found that Oncotype DX testing rates went up from 7.7% in 2005 to 38.8% in 2009.
While this study is limited to women 66 and older who have Medicare insurance, it’s encouraging to know that the Oncotype DX test is being used as recommended by guidelines.
If you’ve been diagnosed with early-stage, hormone-receptor-positive breast cancer and are weighing the pros and cons of adding chemotherapy to your treatment plan, the Oncotype DX test may help you and your doctor make that decision. Besides any genomic test results, you and your doctor will consider other factors when developing your treatment plan, such as:
- your age
- the size of the cancer
- hormone receptor protein levels
- the grade of the cancer
- any other health conditions you have
- your personal preferences
Together, you can make the best treatment decisions for YOU!