The incidence of bone metastasis in advanced breast cancer is 65% to 70%, and the first symptom is bone metastasis in 27% to 50% of patients. The persistent pain and functional impairment caused by bone metastases seriously affect the quality of life of patients. The so-called “bone-related events (SREs)”, which are the observed endpoints of clinical studies of drugs in clinical trials, include increased bone pain or new bone pain, pathological fractures (vertebral fractures, non-vertebral fractures), vertebral compression, deformation, spinal cord compression, symptoms after bone radiotherapy (due to bone pain or prevention of pathological fractures or spinal cord compression), and progression of bone metastases (emergence of new or multiple bone metastases, enlargement of existing bone metastases) and hypercalcemia, which are the main factors affecting the patient’s ability to move autonomously and quality of life. The main objectives of comprehensive treatment of breast cancer bone metastases are to control pain, prevent or treat the occurrence of bone metastasis-related events, and improve the quality of life. Clinical presentation and diagnosis Breast cancer bone metastasis itself is not directly life-threatening, but seriously affects the quality of life. Pain is the first symptom in most patients with bone metastases, and in some cases, pain occurs when the lesion is very small. The initial pain of patients is mostly intermittent. Tumor compression of nerves may cause severe radiating pain in the corresponding distribution area. With the development of the disease, the pain may turn into continuous pain, which is aggravated by activity and not relieved after rest, especially at night when the pain is more obvious. In case of crippling 7 gastric analysis, severe pain, deformity and dysfunction may occur. The vertebral body is the common site of bone metastasis from breast cancer, followed by the rib cage, pelvis, skull, humerus, femur, tibia-fibula and scapula. Bone metastasis sites mainly present as osteolytic lesions. Bone radionuclide scan (ECT) is more sensitive and less specific, and can detect bone metastases early, but it is not easy to distinguish osteogenic lesions from osteolytic lesions, and it cannot show the degree of bone destruction, so it can only be used as a primary screening diagnosis of bone metastases. eCT is recommended for routine primary screening of suspected bone metastases in the presence of bone pain, fracture, elevated alkaline phosphatase or hypercalcemia, T, N.M. or routine screening for patients with recurrent metastatic breast cancer. X-ray plain film/CT or magnetic resonance imaging of the site of suspected bone metastases as indicated by ECT can determine the extent of bone destruction and bone stability. Current. Positron emission computed tomography and biochemical index of bone metabolism cannot be used as routine diagnostic methods. For suspected bone metastases, especially single bone lesions without visceral metastases, performing bone puncture} tongue examination and molecular typing can make a clear diagnosis, which is significant to guide the next treatment. Treatment strategy The goals of treatment for breast cancer bone metastases are to prevent and treat SREs, relieve pain. Restore function, improve quality of life, control Iill mid-tumor progression and prolong survival t, t interval. Breast cancer bone metastasis is a systemic disease, its treatment is also based on systemic treatment, chemotherapy, endocrine therapy, targeted therapy, bisphosphonates can prevent and treat SREs. reasonable local treatment can better control the symptoms of bone metastasis, among which surgery is an active means to treat single bone metastasis lesions, and radiation therapy is an effective local treatment. Systemic systemic therapy Effective systemic antitumor therapy is crucial in the treatment of breast cancer bone metastases, and chemotherapy is an important component of systemic therapy for breast cancer bone metastases. Among patients with recurrent breast cancer, estrogen receptor-positive patients are twice as likely to develop bone metastases as estrogen receptor-negative patients. Related studies have shown that the incidence of bone metastases is significantly higher in breast cancer patients with the Luminal type than in the epidermal growth factor receptor (HER) overexpressing and basal cell types. Current guidelines recommend. Endocrine therapy can be preferred for patients with hormone-responsive breast cancer with slow disease progression, chemotherapy should be preferred for patients with recurrent metastases with rapid disease progression, and trastuzumab alone or in combination can be considered for patients with HER I-2 overexpression type. Bone metastasis of basal breast cancer itself generally does not pose a direct threat to life, and if not combined with visceral metastasis, patients have a relatively long survival period, so unnecessary and intense chemotherapy should be avoided as much as possible. Patients with advanced breast cancer that has been stable for more than 6 months have the same survival as complete remission + partial remission. If the disease remains stable for a long time after treatment then it should be considered as clinical benefit. Endocrine therapy is more suitable for long-term use and the duration of treatment dosing can be maximized to prolong disease control. Everolimus is an inhibitor of the mammalian target of rapamycin and can be used to treat women with advanced postmenopausal breast cancer who are positive for the hormone receptor HER I-2. The results of the BOLERO1 phase I clinical trial suggest that everolimus treatment may be effective in reducing bone metastases from breast cancer. Treatment of Complications Osteolysis is one of the major causes of pain in intractable bone metastases. Osteoclasts accumulate in mineralized bone matrix and lead to bone resorption through enzymatic hydrolysis, while bisphosphonates precisely inhibit osteoclast-mediated bone resorption, and also inhibit the maturation of osteoclasts, and the function of mature osteoclasts and the aggregation of osteoclasts at the site of bone resorption, with tumor cells spreading, infiltrating and adhering to the bone matrix. The National Institute for Health and Clinical Excellence in the UK has suggested that bisphosphonates could be widely used to treat bone complications in patients with advanced breast cancer. And subsequent clinical studies have demonstrated that bisphosphonates can prevent SREs in patients with bone metastases from breast cancer. patients with bone metastases from breast cancer who have an expected survival of >3 months and a myohypophysis <265.2 umol/L should be given bisphosphonates promptly along with chemotherapy and hormonal therapy. Zoledronic acid has been recommended by the American Society of Clinical Oncology as the first-line treatment for bone metastases. The total efficiency of zoledronic acid in relieving cancer pain in patients with breast cancer bone metastases is 92.3%, and the adverse effects are small. Radiation therapy Radiation therapy is an effective method of palliative ron treatment for breast cancer bone metastases, which can prevent or alleviate the symptoms or functional impairment brought about by bone metastases during the survival time of tumor patients. The main role of radiotherapy for the treatment of breast cancer bone metastases is to relieve bone pain and reduce the risk of fractures occurring in the pathology. The effectiveness of treatment can be greatly improved by combining it with bisphosphonates and antitumor therapeutic agents targeting molecular typing. Although radiotherapy is an important local treatment to relieve symptomatic bone metastases. However, it needs to exert anti-tumor effects by receiving radiation and achieve a certain degree of bone repair to show symptom relief, so radiation therapy cannot replace bisphosphonate therapy. For patients who do not achieve definite symptom relief or whose pain is not fully controlled by treatment, pain medication still needs to be given according to the three-step principle. Surgical treatment Surgical treatment can maximize the problem of bone strength loss and nerve compression by pathological gastric tumors in patients with bone metastases from breast cancer, and can reduce pain, restore limb function and improve patients' quality of life. Patients with bone metastases should be closely followed up and observed for early detection of bone metastases, and proper judgment should be made on whether long bones with potential pathological fractures need surgery, so as to strive for effective surgical treatment before fracture and before paraplegia. Surgical treatment of bone metastases from breast cancer includes: (1) simple internal fixation; (2) lesion removal plus internal fixation; (3) lesion removal plus artificial joint replacement; (4) decompression of the spinal cord after compression and reconstruction of spinal stability. Fixation therapy may be considered electively for the treatment of pathologic fractures or for patients with bone metastases from breast cancer with an expected survival time of >34 months after decompression due to spinal cord compression. Prophylactic immobilization may be considered electively for patients with breast cancer metastases with an expected survival time >3 months and with: (1) femoral metastases >2.5 cm in length; (2) femoral neck bone metastases; (3) gastric cortical destruction >50%. Pain medication is the main method to relieve the pain of breast cancer metastases. Pain medication for bone metastases should follow the World Health Organization’s three-step cancer pain management guidelines: (1) Preferred oral and non-invasive routes of administration; (2) Stepwise administration; (3) On-demand administration; (4) Individualized administration; (5) Attention to specific details. Analgesic drugs include NSAIDs, opioid analgesics, and adjuvant medications. NSAIDs are the basic drugs for pain management of bone metastases, and opioid analgesics are recommended when there are several results of pain relief or moderate to severe pain. Timely application of opioid extended-release agents is beneficial for sustained relief of bone pain. However, about 63% of patients with painful bone metastases have sudden onset of pain along with persistent chronic pain. In patients with frequent episodes of sudden pain, pain relief can be achieved by increasing the on-time dose of pain medication. In a minority of patients, pain cannot be controlled by increasing the dose of pain medication on schedule, or even by increasing the dose of medication on schedule because of intolerable adverse drug reactions. The main method of controlling sudden onset pain is to use rapid-acting or short-acting painkillers at a single dose of 5% to 10% of the daily dose. For patients with intractable sudden-onset pain. Consider using the patient-controlled drug pump method of drug administration. When neuropathic pain occurs, adjuvant medication should be selected according to the condition. It should be noted that pain medication can be combined with bisphosphonates and radiation therapy.