Trial confirms some women at low risk of breast cancer recurrence can skip chemotherapy

By John Murphy, MDLinx
Published January 21, 2016

Key Takeaways

Among women with breast cancer who had a low risk of recurrence and were treated with hormone therapy alone, 99% were free of metastatic breast cancer and 98% were free of any recurrence at 5 years, according to findings from the Trial Assigning Individualized Options for Treatment (TAILORx). This therapeutic plan allowed these patients to forgo chemotherapy and its side effects, researchers concluded.   

Investigators undertook TAILORx to determine if a molecular test (Oncotype DX Recurrence Score®)—which assesses the expression of 21 genes associated with breast cancer recurrence among women with early-stage breast cancer—could be used to determine whether hormone therapy plus chemotherapy or hormone therapy alone is the best treatment.

Oncotype DX, developed by Genomic Health, has been available for 10 years but hasn’t been validated in a large prospective clinical trial until now. The study’s results were presented on September 28, 2015 at the 2015 European Cancer Congress, in Vienna, Austria, and simultaneously published online in the New England Journal of Medicine.

Study investigators enrolled more than 10,000 women ages 18 to 75 who had been recently diagnosed with hormone receptor-positive, HER2-negative breast cancer that had not spread to the lymph nodes. Researchers administered the 21-gene recurrence test to all participants from 1,000 sites in the United States, Australia, Canada, Ireland, New Zealand, and Peru.

About 16% of participants had the lowest recurrence scores (0 to 10), and were assigned to receive hormone therapy alone. Women with a score of 11 to 25, who made up 68% of the participants, were randomly assigned to receive hormone therapy alone or hormone therapy plus adjuvant chemotherapy. Researchers assigned women with the highest scores (25 and above) to receive hormone therapy plus adjuvant chemotherapy.

After 5 years, among the participants who had low recurrence scores of 0 to 10, 93.8% of subjects were free of invasive disease and 99.3% were free from recurrence at a distant site, and their overall survival rate was 98%.

“TAILORx is one of the first and most important trials using a gene panel test to determine how to most effectively treat women with breast cancer,” said Jo Anne Zujewski, MD, of the National Cancer Institute’s Cancer Therapy Evaluation Program (CTEP), in Bethesda, MD. “These excellent results in the low-risk subset of women should help spare a significant number of women from being overtreated with chemotherapy.”

While these results are positive, they account for only 16% of the study population. Because nearly 70% of enrollees had a mid-range score of 11 to 25, the trial is ongoing to determine whether this larger subset of women can also be spared chemotherapy.

“We eagerly await the results for all women in the study with the goal of only treating women for their specific type of breast cancer and sparing them the side effects of unnecessary treatments,” Dr. Zujewski said.

TAILORx was sponsored by the National Cancer Institute and led by the ECOG-ACRIN Cancer Research Group with support from Genomic Health.

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