The Study: This trial prospectively randomized 6711 women with hormone receptor-positive, HER2-negative, node-negative breast cancer to endocrine therapy +/- standard chemo. Of note, this included women young and old (18-75 years) with any primary tumor >1 cm up to 5 cm (pT1c-2) any grade or >0.5 cm (pT1b) if grade >1. As a reminder, the longtime standard was for all women with hormone receptor-positive tumors >1 cm to the get chemo. Then we learned with a 2015 landmark trial (on the same cohort as this one) that women with very low Oncotype DX scores (0-10, assigned in single-arm fashion to endocrine therapy alone) can safely say thanks but no thanks to cytotoxic chemo. In this trial, outcomes at 9 years were identical overall between the two treatment arms in regards to both iDFS (83-84%) and overall survival (94%). The only planned subset to see a significant benefit with the addition of chemo were women <50 years with higher-intermediate scores of 16-25.
Bottom line: We finally know what to do with middle ground Oncotype DX scores of 11-26, particularly in women over age 50, which is huge news that will likely affect your treatment recommendations. Maybe even today. | Sparano, N Engl J Med 2018