Oncotype DX Helps Women with Hormone Receptor-positive, HER2-negative, Node-negative Early Stage Breast Cancer Understand Benefit of Chemotherapy
by Dr. C.H. Weaver M.D. 10/2018
Results from the TAILORx clinical trial have demonstrated that many women with early-stage breast cancer (ESBC) may be able to avoid chemotherapy after surgery.
The women who participated in the TAILORx study had hormone receptor-positive, HER2-negative, axillary node-negative ESBC, which is the most common type of breast cancer.
This type of breast cancer is typically treated with hormone therapy, however some women who have a high risk of a breast cancer recurrence also receive chemotherapy following surgery, called adjuvant chemotherapy.
About the Oncotype DX Test:
The Oncotype DX Breast Recurrence Score test provides a genomic-based, individualized risk assessment for early-stage invasive breast cancer in adjuvant that individuals can use to personalize a treatment plan. The Breast Recurrence Score test predicts the likely benefit of chemotherapy as well as the risk of distant recurrence for patients who are newly diagnosed with early stage, ER+, HER2- breast cancer. The test measures the expression of 21 genes: 16 cancer-related genes and five reference genes - in a tumor sample after it has been removed by surgery or biopsy.
A higher score means a higher risk of cancer recurrence and the potential benefit of chemotherapy and a lower score less than 10 suggest only hormone therapy is necessary and chemotherapy can be avoided. Women with mid-range scores of 26 to 100 are typically recommended to receive both hormone therapy and chemotherapy. But there is currently no standard of care for a mid-range score of 11 to 25.
Of the 10,273 women who participated in the TAILORx trial, 6,711 had a mid-range score and were randomly placed into 2 groups. The first group received hormone therapy alone, while the second group received hormone therapy plus chemotherapy. Overall, hormone therapy alone was as effective as hormone therapy plus chemotherapy for many women.
After 9 years, researchers found that for women with a Breast Recurrence Score of 16 to 25.
- About 83% of women receiving only hormone therapy were cancer-free compared with about 84% of those receiving hormone therapy plus chemotherapy.
- Around 95% of women in both groups had not had a distant recurrence.
- Overall survival was about 94% for both groups.
- Adding chemotherapy to hormone therapy was beneficial for women 50 years or younger.
The study results suggest that women older than 50 with a Breast Recurrence Score up to 25 and women age 50 and younger with a score of 15 or below may be able to avoid chemotherapy.
According to lead study author Dr. Joseph A. Sparano, MD, Albert Einstein Cancer Center, Montefiore Health System “Before TAILORx, there was uncertainty about the best treatment for women with a mid-range score of 11-25 on the Oncotype DX Breast Recurrence Score test.
Previous Results From TAILORx:
TAILORx enrolled more than 10,000 breast cancer patients from the United States and Canada. Women in the trial were assigned to a treatment group based on their Oncotype DX Recurrence Score: women with a high Recurrence Score (greater than 25) received adjuvant treatment with chemotherapy plus hormone therapy; women with a low Recurrence Score (less than 11) received adjuvant treatment with hormone therapy alone; and women with an intermediate Recurrence Score (from 11 to 25) were treatedw with adjuvant treatment with either hormone therapy alone or hormone therapy plus chemotherapy. The main focus of the study was to evaluate the Oncotype DX test in women with an intermediate risk of recurrence. In these women the benefit of chemotherapy remained uncertain
Low Oncotype® Recurrence Score® Identifies Group of Women with Early Stage Breast Cancer That can Avoid Chemotherapy.
The results from a group of 1,626 patients with a Recurrence Score between 0 and 10 demonstrated that 99.3 percent of node-negative, estrogen receptor-positive, HER2-negative patients who met accepted guidelines for recommending chemotherapy in addition to hormonal therapy had no distant recurrence at five years after treatment with hormonal therapy alone. Outcomes were excellent irrespective of patient age, tumor size, and tumor grade.
The evidence supports Oncotype DX as the only multi-gene expression assay that can identify patients who can effectively forego chemotherapy.
Oncotype DX™ Influences Breast Cancer Treatment Choices
To explore whether the Oncotype DX test results influence treatment decisions made by medical oncologists and patients, researchers conducted a study among 89 patients who had been treated by 15 medical oncologists at four different medical facilities.
- In roughly 31% of the cases, the test result changed the oncologist’s choice of treatment. The test results also influenced the patient’s choice of treatment.
- The most common change in treatment plan involved a shift away from chemotherapy and hormonal therapy in favor of hormonal therapy alone.
- Paik S, Tang G, Shak S et al. Gene Expression and Benefit of Chemotherapy in Women with Node-Negative, Estrogen Receptor-Positive Breast Cancer. Journal of Clinical Oncology. Early online publication May 23, 2006.
- Lo SS, Norton J, Mumby PB et al. Prospective multicenter study of the impact of the 21-gene recurrence score (RS) assay on medical oncologist (MO) and patient (pt) adjuvant breast cancer (BC) treatment selection. Proceedings of the 43rd Annual Meeting of the American Society of Clinical Oncology. Chicago, IL. June 1-5, 2007. Abstract #577.
- Lyman GH, Cosler LE, Kuderer NM, Hornberger J. Impact of a 21-gene RT-PCR assay on treatment decisions in early-stage breast cancer: an economic analysis based on prognostic and predictive validation studies. Cancer. 2007;109:1011-8.
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