Many women with mid-range scores on the OncoType DX 21-gene expression assay can safely forego postsurgical chemotherapy for early-stage hormone receptor (HR)-positive, HER2-negative, node-negative breast cancer, according to findings from the phase III TAILORx study (abstract LBA1). The findings were presented at a plenary session at the 2018 American Society of Clinical Oncology (ASCO) Annual Meeting, held June 1–5 in Chicago.
The research team identified no disease-free survival benefit associated with chemotherapy over hormone therapy alone.
“Our study showed that chemotherapy may be avoided in about 70% of these women when its use is guided by the test, limiting chemotherapy to the 30% who we can predict will benefit,” reported lead study author Joseph A. Sparano, MD, of the Albert Einstein Cancer Center and Montefiore Medical Center in the Bronx.
Toxicities from chemotherapy for breast cancer can be debilitating. Acute toxicities include nausea and vomiting, neuropathy, hair loss, fatigue, and infection—as well as early menopause and infertility for younger patients.
TAILORx enrolled 10,273 women (10,253 of whom were evaluable) age 18 to 75 years who had HR-positive, HER2-negative, axillary node–negative early breast cancer. Patients were randomly assigned to receive either chemotherapy plus hormone therapy (chemoendocrine therapy) or hormone therapy alone.
The 9-year disease-free survival (DFS) rates and overall survival (OS) rates were nearly identical among women with mid-range scores who were treated with chemoendocrine therapy or hormone therapy alone (9-year DFS, 83.3% vs 84.3%; OS, 93.8% vs 93.8%).
Women with a score of 10 or lower had very few recurrences with hormone therapy alone, Sparano noted.
“Before TAILORx, there was uncertainty about the best treatment for women with a mid-range score of 11 to 25 on the Oncotype DC Breast Recurrence Score test,” Sparano said. “The trial was designed to address this question and provides a very definitive answer. Any woman with early-stage breast cancer 75 years or younger should have the test and discuss results with her doctor to guide her decision regarding chemotherapy after surgery to prevent recurrence.”
“These data provide critical reassurance to doctors and patients that they can use genomic information to make better treatment decisions in women with early-stage breast cancer,” commented ASCO Expert Harold Burstein, MD, PhD, of Dana-Farber Cancer Institute and Brigham & Women’s Hospital in Boston. “Practically speaking, this means that thousands of women will be able to avoid chemotherapy, with all of its side effects, while still achieving excellent long-term outcomes.”