The investigators combined postoperative radiotherapy with CDK4/6 inhibitors ± endocrine adjuvant therapy to explore the tolerability and safety of this treatment regimen in HR+/HER2- postoperative high-risk breast cancer patients. During the study, investigators also utilized PRO scales (FACT-B, FACT-ES, FACT-F) to evaluate patients' multidimensional experiences, such as physical function, emotional state, and treatment-related symptoms, thereby obtaining more authentic and reliable data for symptom assessment and patient benefit.