Women with hormone-receptor-positive, human epidermal growth factor receptor type 2 (HER2)-negative axillary node-negative breast cancer who have tumors with favorable gene-expression profile may have low rates of recurrence at 5 years with endocrine therapy alone, according to a recent study published in The New England Journal of Medicine.1
Researchers led by Joseph Sparano, MD, of the Albert Einstein College of Medicine in New York conducted a prospective trial of 10,253 women who met established guidelines for consideration of adjuvant chemotherapy on the basis of clinicopathologic features.
“A prospectively conducted study in a uniformly treated population provides the highest level of evidence supporting the clinical validity and usefulness of a biomarker,” the authors noted.
They used reverse-transcriptase-polymerase-chain-reaction assay of 21 genes on paraffin-embedded tumor tissue in order to calculate a score that would indicate risk of breast cancer recurrence. A recurrence score of 0 to 10 indicated very low risk, to which these patients were assigned to receive endocrine therapy without chemotherapy.
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Among those observed, 1,626 women had a recurrence score of 0 to 10 and received endocrine therapy alone. At 5 years, these patients were found to have 93.8% rate of invasive disease-free survival, 99.3% rate of freedom from recurrence of breast cancer at a distant site, 98.7% rate of freedom from recurrence of breast cancer at distant or local-regional site, and 98.0% rate of overall survival.
- Sparano JA, Gray RJ, Makower DF, et al. Prospective validation of a 21-gene expression assay in breast cancer. [published online ahead of print September 28, 2015]. N Engl J Med. doi: 10.1056/NEJMoa1510764.