CDK4 and breast cancer: Notably, for both NATALEE and monarchE, nearly all patients received adjuvant chemotherapy, which is generally considered to be the most feared and least proven component of adjuvant therapy in patients with early-stage, high-risk breast cancer [2,3] Although there is no clear evidence that the CDK4/6 inhibitors’ adverse effects are aggravated when preceded by chemotherapy, the review by Giraudo et al. raises the question of whether elderly patients might forgo the (neo)adjuvant chemotherapy phase of therapy.