The Oncotype DX test is a genomic test that analyzes the activity of 21 genes that can affect how a breast cancer is likely to behave and respond to treatment. The Oncotype DX test is used:
- 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
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.
There is also an Oncotype DX DCIS test that is used to help predict the risk of DCIS recurrence.
A study suggests that the Oncotype DX Recurrence Score can help predict survival in people diagnosed with early-stage, hormone-receptor-positive, HER2-negative breast cancer.
The study was published online on June 8, 2016 by Nature Partner Journals Breast Cancer. Read “Breast-cancer-specific mortality in patients treated based on the 21-gene assay: a SEER population-based study.”
To do the study, the researchers looked at the records of 45,287 people diagnosed with hormone-receptor-positive, HER2-negative breast cancer that was not metastatic:
- 40,134 people had node-negative disease, meaning no cancer was found in the lymph nodes
- 4,691 people had up to three lymph positive nodes
- 462 people had four or more positive lymph nodes or missing information on lymph node status
Everyone in the study had had Oncotype DX testing. The records were in the SEER database, a large registry of cancer cases from sources throughout the United States maintained by the National Institutes of Health.
For their primary analysis, the researchers looked at the records of 38,568 people in the study who had node-negative disease and were ages 40 to 84:
- 99.4% were women
- 84% were white
- 25% of the cancers were 1 cm or smaller
- 53% of the cancers were between 1 and 2 cm in size
Half the people in the study were followed for more than 3 years and half were followed for less than 3 years; about 21% of the participants were followed for more than 5 years.
In the primary analysis:
- 21,023 people (55%) had a Recurrence Score of less than 18
- 14,494 people (38%) had a Recurrence Score of 18 to 30
- 3,051 people (8%) had a Recurrence Score that was 31 or higher
The researchers then looked to see how many people had died from breast cancer 5 years after initial diagnosis:
- 0.4% of people with a Recurrence Score lower than 18 had died
- 1.4% of people with a Recurrence Score of 18 to 30 had died
- 4.4% of people with a Recurrence Score of 31 or higher had died
So people with a Recurrence Score lower than 18 were much less likely to die from breast cancer than people with a Recurrence Score of 31 or higher.
The researchers did a second analysis of the 4,691 people in the study with positive lymph nodes:
- 2,694 people (57%) had a Recurrence Score of less than 18
- 1,669 (36%) had a Recurrence Score of 18 to 30
- 328 (7%) had a Recurrence Score that was 31 or higher
Five years after their initial diagnosis:
- 1.0% of people with a Recurrence Score lower than 18 had died
- 2.3% of people with a Recurrence Score of 18 to 30 had died
- 14.3% of people with a Recurrence Score of 31 or higher had died
The link between the Recurrence Score and the risk of dying from breast cancer was statistically significant, which means that the link wasn’t just due to chance.
The researchers pointed out that the risk of dying from breast cancer was 1.3% or lower for people with a Recurrence Score lower than 18, no matter if the lymph nodes were positive or negative.
“Prior to our study, there were relatively little data regarding Recurrence Score results and outcomes in younger and older patients with breast cancer,” the researchers wrote. “Our population-based SEER study is therefore noteworthy for providing the largest experience to date with patients 70 years of age or older, including 4,647 with node-negative disease and 880 with node-positive disease, and with patients younger than 40 years, including 1,480 with node-negative disease and 165 with node-positive disease. Our study found that regardless of age, patients with Recurrence Score results of less than 18 had excellent outcomes.”
If you’ve been diagnosed with early-stage, hormone-receptor-positive, HER2-negative 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. If your Recurrence Score is low, you may be able to skip chemotherapy and have excellent outcomes. If your Recurrence Score is higher, your doctor may recommend chemotherapy. It’s important to remember that many women with higher Recurrence Scores have excellent outcomes after they get the treatment that is best for their unique situation.
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!