Study: Most Women with Early Breast Cancer…

Study: Most Women with Early Breast Cancer…

…Do Not Benefit from Chemotherapy

New findings from the groundbreaking 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-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, released at the American Society of Clinical Oncology annual meeting, will help inform treatment decisions for many women with early-stage breast cancer.

“The new results from TAILORx give clinicians high-quality data to inform personalized treatment recommendations for women,” says lead author Joseph A. Sparano, md, associate director for clinical research at the Albert Einstein Cancer Center and Montefiore Health System in New York, NY, 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 is a phase 3 clinical trial that 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.

When women enrolled in the trial, their tumors were analyzed using the 21-gene expression test, and they were assigned a risk score for cancer recurrence. Based on evidence from earlier trials, women in the trial who had a score in the low-risk range received hormone therapy only, and those who had a score in the high-risk range were treated with hormone therapy and chemotherapy.

Women in the trial who had a score in the intermediate range 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.

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. According to the authors, the new findings suggest that chemotherapy may be avoided in about 70 percent of women with HR-positive, HER2-negative, node-negative breast cancer. This data adds to findings from a TAILORx analysis published in 2015 that provided prospective evidence that the gene expression test could identify women with a low risk of recurrence who could be spared chemotherapy.

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There is one caveat to the new findings. When the researchers analyzed premenopausal women and those younger than 50 years old at the higher end of the intermediate-risk range separately, the results showed there may be a small benefit from chemotherapy, and thus these women should consider chemotherapy. However, it is unclear if this benefit is due to the effect of chemotherapy or to endocrine suppression caused by chemotherapy-induced menopause.

“Before TAILORx, there was uncertainty about the best treatment for women with a mid-range score on the Oncotype DX Breast Recurrence Score test. The trial was designed to address this question and provides a very definitive answer,” says Dr. Sparano. “Any woman with early-stage breast cancer age 75 or younger should have the 21-gene expression test and discuss the results with her doctor to guide her decision to the right therapy.”

The trial was supported by the National Cancer Institute, part of the National Institutes of Health, and designed and led by the ECOG-ACRIN Cancer Research Group. Findings from the study were published in The New England Journal of Medicine.