Low Risk of Recurrence Could Mean No Chemotherapy for Hormone-Positive Breast Cancer
A very large breast cancer trial recently found that women with a very low Recurrence Score – a number that suggests the overall risk of cancer returning – can be treated well with hormonal therapy alone. Traditionally, this group receives both hormonal therapy and chemotherapy. The finding means one group of women with breast cancer can avoid chemotherapy and its side effects, without risk to their health.
In 2001, the National Institutes of Health recommended that chemotherapy be given widely to women with breast cancer. Since then, the use of chemotherapy has led to lower rates of death from breast cancer in the United States and other countries.
Yet some studies suggested that not all women needed chemotherapy if they were being treated with other anticancer medicines like hormonal therapy. Hormonal therapy is given to women with breast cancer that grows because of the hormones estrogen or progesterone, called hormone receptor-positive disease. The medicine slows or stops the activity of these hormones, which stops the growth of cancer cells.
Other studies showed that using a test known as a 21-gene expression assay, Oncotype DX, could help doctors predict whether chemotherapy was necessary for certain breast cancers. Oncotype DX assigns the cancer a Recurrence Score, a measure of how likely it is to come back, or recur. Researchers believed a low Recurrence Score could mean less treatment with chemotherapy.
The researchers on this trial, Trial Assigning Individualized Options for Treatment (TAILORx), wanted to find out who could safely avoid chemotherapy.
TAILORx enrolled 10,253 women with hormone receptor-positive breast cancer who were 18 to 75 years old and who would generally be recommended chemotherapy along with hormonal therapy. No participant had cancer in their lymph nodes or HER2-positive disease, which is treated with a different kind of anticancer medicine.
The research team used Oncotype DX to test tumor samples from each woman, and assigned treatment based on three groups of Recurrence Score. Scores of
- 0 to 11 received hormonal therapy alone
- 11 to 25 received either
- hormonal therapy alone, or
- hormonal therapy plus chemotherapy
- 25 or higher received hormonal therapy plus chemotherapy
At this time, only the results for the lowest Recurrence Score group (0 to 11) are available. Researchers are still following the mid-range (11 to 25) group.
The data showed that at 5 years in the group treated with only hormonal therapy
- 99.3 percent had not had breast cancer come back in a site far from the breast (some may have had breast cancer spread to nearby sites, such the lymph nodes of the armpit)
- 98.7 percent never had the breast cancer come back at all
This means that in this group, at 5 years on only hormonal therapy
- the risk of recurrence far from the breast was less than 1 percent
- the risk of any recurrence, nearby or distant, was less than 2 percent
These results show that for this group of women, chemotherapy was not needed to protect them from the cancer coming back during the first 5 years after treatment.
What This Means for You
The results of TAILORx show that using the Oncotype DX Recurrence Score can help doctors decide whether a woman needs chemotherapy as part of her treatment plan.
If you are a woman with hormone receptor-positive breast cancer and your tumor has a low Recurrence Score, you may be able to skip treatment with chemotherapy. If you are able to avoid chemotherapy safely, you avoid the side effects that come with it. Though these results show confidence in the Oncotype DX test, not all doctors may start using it immediately. It’s OK to ask your care team how they think this study will impact your treatment plan.
TAILORx only reported on the impact of therapy on the first 5 years after treatment, a time during which risk of recurrence is often lower in hormone receptor-positive breast cancer. Recurrences that happen after 5 years are not well understood and more research is needed.
Sparano, Joseph A; Gray, Robert J; Makower, Della F et al. Prospective Validation of a 21-Gene Expression Assay in Breast Cancer. New England Journal of Medicine. September 28, 2015. DOI: 10.1056/NEJMoa1510764