TAILORx trial finds most women with early breast cancer do not benefit from chemotherapy

 New findings from the groundbreaking Trial Assigning Individualized Options for Treatment (Rx), or TAILORx trial, show no benefit from chemotherapy for 70 percent of women with the most common type of breast cancer. The study found that for women with hormone receptor (HR)-positive, HER2-negative, axillary lymph node-negative breast cancer, treatment with chemotherapy and hormone therapy after surgery is not more beneficial than treatment with hormone therapy alone. The new data will help inform treatment decisions for many women with early-stage breast cancer.

The trial was supported by the National Cancer Institute (NCI), part of the National Institutes of Health, and designed and led by the ECOG-ACRIN Cancer Research Group.

“The new results from TAILORx give clinicians high-quality data to inform personalized treatment recommendations for women,” said lead author Joseph A. Sparano, M.D., associate director for clinical research at the Albert Einstein Cancer Center and Montefiore Health System in New York City and vice chair of the ECOG-ACRIN Cancer Research Group. “These data confirm that using a 21-gene expression test to assess the risk of cancer recurrence can spare women unnecessary treatment if the test indicates that chemotherapy is not likely to provide benefit.”

TAILORx, a phase 3 clinical trial, opened in 2006 and was designed to provide an evidence-based answer to the question of whether hormone therapy alone is not inferior to hormone therapy plus chemotherapy. The trial used a molecular test (Oncotype DX Breast Recurrence Score) that assesses the expression of 21 genes associated with breast cancer recurrence to assign women with early-stage, HR- positive, HER2-negative, axillary lymph node–negative breast cancer to the most appropriate and effective post-operative treatment. The trial enrolled 10,273 women with this type of breast cancer at 1,182 sites in the United States, Australia, Canada, Ireland, New Zealand, and Peru.

When patients enrolled in the trial, their tumours were analysed using the 21-gene expression test and assigned a risk score (on a scale of 0–100) for cancer recurrence. Based on evidence from earlier trials, women in the trial who had a score in the low-risk range (0–10) received hormone therapy only, and those who had a score in the high-risk range (26 and above) were treated with hormone therapy and chemotherapy.

Women in the trial who had a score in the intermediate range (11–25) were randomly assigned to receive hormone therapy alone or hormone therapy with adjuvant chemotherapy. The goal was to assess whether women who received hormone therapy alone had outcomes that were as good as those among women who received chemotherapy in addition to hormone therapy.

“Until now, we’ve been able to recommend treatment for women with these cancers at high and low risk of recurrence, but women at intermediate risk have been uncertain about the appropriate strategy to take,” said Jeffrey Abrams, M.D., associate director of NCI’s Cancer Therapy Evaluation Program. “These findings, showing no benefit from receiving chemotherapy plus hormone therapy for most patients in this intermediate-risk group, will go a long way to support oncologists and patients in decisions about the best course of treatment.”

The researchers found that the primary endpoint of the trial, invasive disease-free survival—the proportion of women who had not died or developed a recurrence or a second primary cancer—was very similar in both groups. Five years after treatment, the rate of invasive disease-free survival was 92.8 percent for those who had hormone therapy alone and 93.1 percent for those who also had chemotherapy. At nine years, the rate was 83.3 percent for those with hormone therapy alone and 84.3 percent for the group that had both therapies. None of these differences were considered statistically significant.

The rates of overall survival were also very similar in the two groups. At five years, the overall survival rate was 98.0 percent for those who received hormone therapy alone and 98.1 percent for those who received both therapies, and at nine years the respective overall survival rates were 93.9 percent and 93.8 percent.

The researchers also found that women with a score of 0–10 had very low recurrence rates with hormone therapy alone at nine years (3 percent). This confirms similar findings from earlier studies. In addition, they found that women with a score of 26–100 had a distant recurrence rate of 13 percent despite receiving both chemotherapy and hormone therapy. This finding indicates the need to develop more effective therapies for women at high risk of recurrence.

 

ECOG-ACRIN Cancer Research Group
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