Image: The Oncotype Dx tests 21 genes related to breast cancer (Photo courtesy of NEJM).
A new study found no difference in disease-free survival of women with axillary node-negative breast cancer (BC) treated with endocrine therapy alone, or with a combination of endocrine therapy with chemotherapy.
Researchers at the Montefiore Einstein Center for Cancer Care (MECCC; New York, NY, USA), Northwestern University (NU; Chicago, IL, USA), and other institutions conducted a prospective trial involving 10,273 women with hormone-receptor–positive, human epidermal growth factor receptor 2 (HER2)–negative, axillary node-negative breast cancer, as assessed by the Genomic Health (Redwood City, CA, USA) Oncotype Dx test.
In all, 9,719 eligible patients were available for follow-up information, of which 69% had a midrange Oncotype Dx test recurrence score of 11-25. The women in the midrange group were then randomly assigned to receive either adjuvant chemoendocrine therapy or endocrine therapy alone. The trial was designed so as to show non-inferiority of endocrine therapy alone for invasive disease–free survival, defined as freedom from invasive disease recurrence, second primary cancer, or death.
The results revealed that at nine years follow-up, the two treatment groups had similar rates of invasive disease–free survival (83.3% in the endocrine-therapy group and 84.3% in the chemoendocrine-therapy group), freedom from disease recurrence at a distant regional site (94.5% and 95%, respectively), at a local site (92.2% and 92.9%), as well as overall survival (93.9% and 93.8%). A chemotherapy benefit was found only in women 50 years of age or younger with a recurrence score of 16-25. The study was published on June 3, 2018, in the New England Journal of Medicine (NEJM).
“In terms of the big picture and the impact on care, application of this test in clinical practice will spare an estimated 70% of patients and limit chemotherapy to the 30% who may benefit from it,” said lead author Joseph Sparano, MD, associate director for clinical research at MECCC. “A very important finding was that … we found an interaction between age and recurrence score. Women younger than 50 years with a recurrence score of 16 to 25 received some benefit from chemotherapy. This information can drive some women with recurrence scores in this range to accept chemotherapy.”
The Oncotype DX genomic test analyzes the activity of 21 genes to provide prognostic information in hormone receptor–positive breast cancer, with a recurrence score that ranges from 0 to 100. Patients who obtain a high score (defined as 26 or higher) are considered to be at high risk for relapse; patients who obtain a low score (0-10) are considered to have a very low rate of distant recurrence.
Montefiore Einstein Center for Cancer Care