The 70-gene signature test, MammaPrint, in combination with standard clinical-pathologic criteria, may help clinicians decide whether patients with early stage breast cancer who are at high clinical risk require adjuvant chemotherapy, according to a study published in The New England Journal of Medicine.1
Previous research has demonstrated that the 70-gene signature test improves prediction of clinical outcome in patients with early stage breast cancer. Therefore, researchers sought to prospectively evaluate the clinical utility of adding MammaPrint to a modified version of Adjuvant! Online in selecting patients for adjuvant chemotherapy.
For the phase 3 trial, investigators enrolled 6693 women and used MammaPrint and a modified Adjuvant! Online to determine their genomic risk and clinical risk, respectively.
Women with low clinical and genomic risk did not receive chemotherapy, while patients with high clinical and genomic risk did receive adjuvant chemotherapy. In cases where genomic risk is high and clinical risk is low, or vice versa, either risk assessment was used to determine whether chemotherapy would be used.
Results showed that the 5-year distant metastasis-free survival rate was 94.7% (95% CI, 92.5-96.2) among those at high clinical risk and low genomic risk who did not receive chemotherapy. This rate was 1.5% lower than the rate with chemotherapy.
Subgroup analyses further demonstrated similar distant metastasis-free survival rates in women with estrogen receptor-positive, HER2-negative, and either node-negative or node-positive disease.
These findings ultimately suggest that approximately 46% of patients with early stage breast cancer at high clinical risk may not require chemotherapy.
1. Cardoso F, van’t Veer LJ, Bogaerts J, et al. 70-gene signature as an aid to treatment decisions in early-stage breast cancer. N Engl J Med. 2016;375:717-729.