Rationale and Trial Design of DAWNA‐FES Trial: Single‐Arm Phase II Study of Endocrine Therapy With Dalpiciclib After Progression on CDK4/6 Inhibition Based on [18F]FES PET/CT in Patients With HR+/HER2− Advanced Breast Cancer. - Yao, Ru; Qu, Yang; Hao, Zhixin; Xu, Ying; Zhang, Jiahui; Lian, Jie; Gao, Lu; Shen, Songjie; Mao, Feng; Pan, Bo; Sun, Qiang; Huo, Li; et al. (Cancer Innovation, 2026)