By analyzing the clinical data of patients with advanced breast cancer with bone metastasis admitted to our center from January 1, 2021 to February 28, 2023, this study aims to understand the real-world clinical diagnosis and treatment of breast cancer with bone metastasis, including the epidemiology of bone metastasis, screening and diagnosis methods, selection of clinical treatment methods, and occurrence of SRE. To explore the risk factors related to bone metastasis-free survival (BMFI). In addition, we will explore the use of quantitative analysis of CT values to evaluate bone metastases of breast cancer, aiming to provide a new method for imaging quantitative efficacy evaluation of bone metastases.

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.

Inclusion Criteria:

1. Age ≥18y;
2. Advanced breast cancer is clearly diagnosed;
3. Imaging or pathology confirmed at least 1 bone metastasis;
4. No history of other malignant tumors at the time of initial diagnosis;
5. The physical status score of Eastern Tumor Collaboration Group (ECOG) was ≤2 points;
6. Complete clinical and follow-up data.

Exclusion Criteria:

Exclusion is defined as meeting 1 of the following exclusion criteria:

1. Patients with other malignant tumors;
2. History of hyperthyroidism and hypothyroidism, abnormal parathyroid function;
3. History of bone metabolic diseases.

All eligible patients admitted to Zhejiang Cancer Hospital from January 1, 2021 to February 28, 2023 were included