Gene Assay Informs Chemo Decision in Breast Cancer 10-year recurrence risk of 3.5% in low-risk, node-positive disease

This study identified a substantial population of patients with one to three positive lymph nodes with sufficiently low risk to safely avoid chemotherapy. By tailoring risk categorization to the number of positive nodes, 37% of patients with a single positive lymph node and 15% of patients with two positive nodes were characterized as low risk, by Prosigna, with very favorable outcomes when treated with adjuvant endocrine therapy alone. "Although chemotherapy could still provide some relative additional benefit for patients, when the low-risk group carries a residual rate of recurrence of <5% at 10 years, the absolute benefit that can be achieved by still giving chemotherapy could be, at best, very small (and more than counterbalanced by toxicities)."