Results of Gene Panel Test Can Determine Need for Chemotherapy in Breast Cancer

A prospective study that enrolled more than 10,000 women with hormone-receptor—positive, HER2-negative breast cancer has found that their response to a 21-gene test can identify patients who can avoid chemotherapy.

A prospective study that enrolled more than 10,000 women with hormone-receptor (HR)—positive, HER2-negative breast cancer has found that their response to a 21-gene test can identify patients who can avoid chemotherapy. Published in the New England Journal of Medicine, the trial found that in women who scored 10 or lower on the test and received standard hormone therapy such as tamoxifen without chemotherapy, there was less than a 2% risk of the cancer spreading to nearby or distant sites and the 5-year overall survival was 98%.

This paper in NEJM reports the results of the Trial Assigning Individualized Options for Treatment (TAILORx), designed to validate the clinical usefulness of Genomic Health’s 21-gene assay called Oncotype DX in women with low-risk, HR-positive, HER2-negative, axillary node—negative invasive breast cancer. Participants were women 18 to 75 years of age who met the National Comprehensive Cancer Network guidelines for the recommendation of adjuvant chemotherapy. They also had to meet the Eastern Cooperative Oncology Group performance-status score of 0 or 1.

Analysis of trial results found that nearly 16% of women had a multigene test score of 10 or lower, while another 68% had a mid-range score of 11 to 25. The rate of invasive disease-free survival in those with a score of 10 or less was 93.8% at 5 years, the rate of freedom from recurrence of breast cancer at a distant or loco-regional site was 98.7%, and rate of overall survival was 98%.

“This should provide a lot of reassurance to women and their physicians,” said Kathy Albain, MD, FACP, FASCO of Loyola University Medical Center and Loyola University Chicago Stritch School of Medicine, a coauthor on the paper. “In women whose breast cancer scored low on the multigene test, there was outstanding survival with endocrine therapy alone. The test provides us with greater certainty of who can safely avoid chemotherapy.”