The 70-gene signature test may help patients with early-stage breast cancer avoid unneeded chemotherapy, according to the results of a study published in The New England Journal of Medicine.
The 70-gene signature test has demonstrated predictive value in patients with early-stage breast cancer, though its use is limited to specific clinical scenarios. In a prospective study led by Fatima Cardoso, MD, Champalimaud Clinical Center (Lisbon, Portugal), researchers evaluated the clinical utility of adding the test to standard clinical-pathological criteria when selecting patients for adjuvant chemotherapy.
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For the study, researchers enrolled 6693 women with early-stage breast cancer and determined their genomic and clinical risk using the 70-gene signature test and a modified version of Adjuvant! Online, a suite of online tools that assist patient and physician decision-making during early cancer care. Patients deemed low clinical and genomic risk received chemotherapy, while those at high risk did not receive such therapy.
A total of 1550 women were deemed to be at high clinical risk and low genomic risk. At 5 years, the rate of survival without distant metastasis in this group was 94.7%. among those who did not receive chemotherapy. Additionally, there was a difference of 1.5 percentage points in survival between patients who did and did not receive chemotherapy, with the rate being lower without chemotherapy. These results were consistent across subgroups of patients with estrogen receptor-positive, human epidermal growth factor receptor 2-negative, and either node-negative or node-positive disease.
Researchers concluded that, among women with early-stage breast cancer who were at high clinical risk and low genomic risk for recurrence, not receiving chemotherapy on the basis of the 70-gene signature test led to a 5-year rate of survival without distant metastasis that was shorter than the rate observed with chemotherapy. These findings indicate that almost half (46%) of women with breast cancer who are at high clinical risk might not require surgery.
