The specific contents of our research include the basic information of breast cancer patients with bone metastasis in the early stage, neoadjuvant therapy, surgery and postoperative pathology, and adjuvant therapy; The time and location of recurrence and metastasis, treatment plan, and information related to bone metastasis include time, location, diagnosis method, treatment, occurrence of SRE, and changes in CT values of bone lesions before and after drug treatment. The objective is to understand the risk factors of bone metastasis-free survival (BMFI) of breast cancer patients with bone metastases in the real world, provide evidence and data for clinical accurate screening, observe the CT value changes of bone lesions through imaging (CT quantitative), and explore a new method for evaluating the efficacy of bone metastases.