The ASTER 70s study by Etienne Brain and colleagues is a landmark phase 3 study. It defines the treatment strategy in older women aged 70 years and older with HER2-negative estrogen receptor-positive breast cancer. The overall result of the study is insignificant. However, in a subgroup of patients with pT1 tumors, it shows a signal: the chemotherapy group had an 8-year overall survival of 76.7% versus 84.5% in the group with hormone therapy alone. The hazard ratio (HR) is 0.51 (95% CI 0.6 otherwise). This suggests a traditional treatment effect of 0.27–0.