The overall treatment strategy for bone metastases is palliative treatment, which can be broadly categorized into two main groups: 1. Improvement of symptoms, prevention and treatment of bone-related events, and improvement of quality of life; 2. Anti-tumor therapy to prolong survival time. I. Improvement of symptoms, prevention and treatment of bone-related events, and improvement of quality of life Analgesic treatment: pain is the most important factor affecting the life treatment of patients with bone metastases. Continuous and effective relief of bone pain is the main strategy for the treatment of bone metastases of malignant tumors. Methods to relieve bone pain methods include: analgesic drugs, bisphosphonates, radiation therapy and so on. Analgesic drugs such as opioids can relieve pain timely and effectively, and play an irreplaceable role in the treatment of bone pain.The three-step analgesic treatment proposed by WHO is a worldwide recognized treatment method for cancer pain, which refers to the selection of analgesic of corresponding strength according to the patient’s degree and cause of pain, and the use of the analgesic escalates gradually from weak to strong and the use of the medication is guided by the following principles: 1. Oral and non-invasive routes of administration: oral administration is convenient, safe, and easy to be accepted by patients. Convenient, safe and easy to be accepted by patients, especially the emergence of extended-release preparations is more convenient for long-term oral administration. For those who have difficulty in swallowing, gastrointestinal obstruction or obvious reaction of vomiting after administration, rectal suppository or transdermal patch can be used; 2. Administering drugs on time: the analgesic treatment of cancer pain should avoid the concept of “administering drugs when necessary”, and should be administered according to the law of metabolism of drugs in the body and the play of analgesic effect, and should be given according to a planned schedule. Different drugs should be given at different intervals, for example, morphine immediate-release tablets should be given every 4h, morphine controlled-release tablets should be given every 8-12 hours, and fentanyl transdermal patches should be given every 72 hours. 3. Give drugs according to the ladder: i.e., three-steps of medication should be given, and the main choice of patients with mild pain should be the antipyretic and analgesic analgesic, such as aspirin and paracetamol, and patients with moderate pain should be the main choice of weak opioid analgesic, which is the best choice. For mild pain, patients should mainly use antipyretic analgesics, such as aspirin and paracetamol; for moderate pain, patients should mainly use weak opioid analgesics, such as codeine and tramadol; for severe pain, patients should mainly use strong opioid analgesics, such as morphine and fentanyl patches; 4. Individualization of the dosage of medication: there are large differences in the degree of response to analgesic medication between different patients, so analgesic treatment should be individualized to achieve an ideal analgesic effect by choosing the appropriate analgesic medication and dosage. 5: During the treatment period, attention should be paid to the observation of efficacy and adverse reactions, timely adjustment of the dose of medication, if the number of times per day temporary addition to the number of times more than 3 times, should be considered to increase the daily dose of medication on time, if there is a significant adverse reaction, it should be timely to replace the analgesic drugs or reduce the dose. Bisphosphonate drug therapy: bisphosphonates have the effect of selectively inhibiting osteoclast activity and inhibiting osteolysis and resorption, which can relieve bone pain, restore normal function and reduce the risk of bone-related events. a meta-analysis of bisphosphonate studies published by Ross et al. in 2003 showed that most of the findings support the conclusion that bisphosphonates can relieve bone pain and reduce bone-related events. Bisphosphonates are commonly used in clinical practice. Commonly used bisphosphonates in clinical practice include clodronic acid, pamidronic acid, ibandronic acid, and zoledronic acid, which have been widely used in the treatment of bone metastases from multiple myeloma, breast cancer, prostate cancer, lung cancer, and many other solid tumors. The dosage and usage of commonly used bisphosphonates: pamiphosphate: 90mg iv >2h, repeated every 3-4 weeks; ibandronate: 6mg iv >2h, repeated every 3~4 weeks; zoledronate 4mg iv >15min, repeated every 3-4 weeks. Bisphosphonates can also be administered by the oral route. Moreover, it has been shown that there is no difference in efficacy between oral and intravenous administration for bone-related events. Oral administration provides easy application and good tolerability, which increases patients’ adherence to treatment. Radiation therapy:Radiation therapy can kill bone tissue tumor cells, reduce the size of the tumor, reduce periosteal tension, and inhibit the release of pain-causing chemicals from bone cells, thus reducing or relieving pain, and at the same time, it can also reduce the occurrence of pathologic fracture and reduce the compression of the tumor on the spinal cord, and the occurrence of bone-related events, which can significantly improve the quality of survival of patients with bone metastatic tumors. The methods of radiation therapy are divided into extracorporeal irradiation and intracorporeal irradiation. Extracorporeal irradiation is a common and effective method for palliative treatment of bone metastases, and it is routinely used in low-division radiotherapy or word radiotherapy techniques. There are two common dosages and division methods for low-division radiotherapy: 300cGy/times, 10 times in total; 400cGy/times, 5 times in total; and a single irradiation dose of 800cGy. The advantages of single irradiation are that the near-term therapeutic efficacy and adverse effects are the same as those of multiple-division irradiation, and the treatment cycle is short and the cost is low, which is especially suitable for patients with bone metastases who have a short life expectancy, as well as patients who have difficulty in moving and lifting. It is also used for patients with difficulty in mobility and lifting. The disadvantage of single radiation therapy is that long-term survivors of irradiation site pain in radiotherapy and the incidence of pathologic fracture is higher than that of fractionated radiation therapy. Systemic radionuclide internal irradiation therapy is effective in relieving bone pain in systemic extensive bone metastases. At present, the more commonly used internal radiotherapy drugs 89Sr and 153Sm-EDTMP, etc., the domestic use is more 153Sm-EDTMP, EDTMP is ethylenediamine tetramethylenephosphonate, play the role of carrier, 153Sm-EDTMP in the lesion of the bone affinity is 16 times higher than that of the normal bone, can be more specific to the tumor cells to produce radiotherapy, and 153Sm-EDTMP is easy to prepare, and 153Sm-EDTMP can be more specific for tumor cells, but also can be more specific for tumor cells, and 153Sm-EDTMP is easy to prepare, and 153Sm-EDTMP is easy to use. EDTMP is easy to prepare, inexpensive, and can be used multiple times. The incidence of myelosuppression in systemic radionuclide therapy is relatively high and recovery is slow, and patients who have received high-dose radiotherapy are prone to severe myelosuppression, so it is only selectively applied to patients with systemic extensive bone metastases. Management and prevention of bone-related events: For pathologic fractures, spinal instability, and spinal cord compression caused by bone metastases, non-surgical treatments are usually difficult to achieve definitive efficacy, and often require surgical intervention. For pathological fractures of the extremities, we advocate surgical internal fixation if the patient’s general condition permits. The principle of surgery should be: remove part of the diseased bone tissue and perform strong internal fixation, even if the fracture does not heal after surgery, it can reduce the pain of the patient after surgery and improve the quality of life. Interlocking intramedullary nails should be the first choice of fixation equipment. Interlocking intramedullary nails have high strength, the locking nail is far away from the fracture, and the fixation is firm, so there is no need to assist the external fixation of plaster after the operation, and the patient can carry out appropriate activities without weight bearing in the early stage, and the disadvantage that the nails and plates are not solidly fixed after fixation of the steel plate due to the destruction of the bone at the place of the pathologic fracture can be avoided. Bone cement has the advantages of filling irregular cavities and immediate weight bearing, especially for the treatment of trochanteric fractures, it can fill the medial cortical defect and reduce the tendency of inversion, and it can restore the role of tension trabeculae when combined with metal internal fixation and overcome the rotational torque force, which can greatly improve the upper end of the femur’s pressure-bearing capacity. If the pathologic fracture occurs at one end of the long bones of the limb, such as the femoral neck and the intertrochanteric femur, the upper humerus, the distal femur and the proximal tibia, artificial arthroplasty can be performed, and the distal end of the prosthesis can be fixed with bone cement. Pathological fractures of the distal extremities, such as around the forearm and ankle joints, are often well fixed by external fixation with plaster or braces. Prophylactic internal fixation can be performed for bone metastases that are heavily weight-bearing and have severe bone destruction.The Mirels scoring system quantifies bone metastases on the verge of pathological fracture according to the location of the metastasis, the degree of pain, and the nature and extent of the destruction (Table 1). When the score is ≤7, the possibility of fracture is small, and non-surgical treatment, such as radiotherapy, bisphosphonate treatment, etc., is feasible; when the score is ≥8, the possibility of fracture is large, and internal fixation should be done first to prevent the occurrence of pathological fracture. Table 1 Bone metastases on the verge of pathological fracture scoring table 1 score 2 scores 3 scores Part Upper limb Lower limb Femoral rotor part Pain degree Mild Moderate Severe (functional impact) Nature of destruction Osteogenic Mixed Osteolytic Range of destruction 1/3 1/3~2/3 2/3 Spinal metastasis can cause spinal instability, spinal cord compression, and even complete paraplegia, which seriously threaten the patients’ life and quality of survival. The indications for surgery of spinal metastases are as follows: (1) spinal instability caused by spinal metastases; (2) pain that cannot be relieved by radiotherapy, or recurrence or worsening after radiotherapy or chemotherapy; (3) progressive spinal cord or nerve function impairment; (4) unknown primary tumor or unknown histopathological diagnosis, surgery is performed at the same time of taking biopsy. Traditional surgery can be divided into anterior surgery, posterior surgery and combined anterior and posterior surgery. Anterior surgery, because of the proximity of abdominal blood vessels and other organs, has relatively more complications. It is suitable for those whose tumors are mainly located in the vertebral body and the compression comes from the front, and it is feasible to use anterior decompression, artificial vertebral body or cement fixation; posterior surgery is less traumatic, and can be very good for patients with the pain caused by nerve root compression, and it is suitable for those whose tumors are located in the back, or when more than two consecutive vertebral bodies are involved, and it is feasible to use laminectomy and decompression and internal fixation. For cervical and thoracic metastases, the anterior tumor resection should be completed first, and if the posterior accessory system is destroyed by the tumor, or if it is difficult to fix the low lumbar vertebrae anteriorly, the anterior and posterior combined fixation can be considered. If the spinal metastases do not have pathological fracture, or if compression fracture has occurred without obvious nerve compression symptoms, percutaneous vertebroplasty (PVP) can be used.PVP was firstly used for painful vertebral hemangiomas, and then it was gradually popularized to be used with vertebral compression fracture caused by osteoporosis or malignant tumors, and it can rapidly provide pain relief, increase spinal strength and stability for spinal metastases, PVP is to inject the debugged bone cement into the damaged vertebral body with a puncture needle under fluoroscopic monitoring to support and stabilize the spine, and the surgery has the advantages of minimally invasive, safe, and effective, which is now receiving more and more attention and promotion. Second, anti-tumor treatment, prolong survival time Most of the malignant tumors with bone metastases have already received chemotherapy for many times, and they are already resistant to many kinds of chemotherapeutic drugs, so the traditional chemotherapy is often ineffective in relieving bone pain and treating bone metastases. However, some data show that combination chemotherapy can obtain a certain remission rate and prolongation of survival [8]. The choice of chemotherapeutic agents is mainly based on the cytologic nature of the primary foci. The chemotherapy regimen mostly adopts triple drugs,? The commonly used drugs include paclitaxel, cisplatin, pirarubicin, fluorouracil, gemcitabine, and vincristine. Patients who are resistant to multiple chemotherapeutic drugs but in good general condition are encouraged to participate in clinical trials. Endocrine therapy is mainly used for hormone-dependent tumors such as breast cancer, prostate cancer and thyroid cancer. Endocrine therapy drugs can not only inhibit the growth of tumor cells, but also provide pain relief for patients with bone metastases. It is also important for patients with bone metastasis in terms of pain relief, improvement of quality of life and reduction of bone marrow suppression with chemotherapy. Commonly used endocrine therapy drugs for breast cancer include aromatase inhibitors (AIs), progestins and anti-estrogens. , progestins and anti-estrogens (triamcinolone acetonide, anastrozole), for hormone-positive breast cancer bone metastases,? Endocrine therapy is especially important. Inhibiting or controlling the growth of prostate cancer cells by lowering the level of androgen or blocking its binding to the receptor is the most basic treatment for advanced prostate cancer, and most of the patients have a good therapeutic effect. The methods of endocrine treatment include: drug and surgical debulking and combination of debulking and androgen receptor blockers. Commonly used drugs are mainly luteinizing hormone-releasing hormone (LHRH)? analogs (? such as inhibinatone and norethindrone)? , steroids and non-steroidal anti-androgens. In terms of immunotherapy, the epidermal growth factor receptor (EGFR) and its inhibitors have been the most studied this year. Overexpression of EGFR is associated with poor prognosis, rapid metastasis, and short survival.EGFR inhibitors have the potential to achieve their anti-tumor effects through pro-apoptosis, anti-angiogenesis, anti-differentiation and proliferation, and anti-cell migration. They are often used in combination with chemotherapy and radiotherapy to achieve synergistic effects. Currently, the more commonly used EGFR inhibitors include Iressa (Iressa), Cetuximab (Ebituxan), Tarceva (Tarceva) and so on. It is mainly used in the treatment of advanced gastric cancer, colon cancer, pancreatic cancer, lung cancer, etc. Herceptin also plays an important role in the treatment of breast cancer, and is mainly applied to patients with positive expression of human epidermal growth factor receptor-2 (HER-2), which is an inhibitor of HER-2, accelerating the degradation of HER-2 and inhibiting the malignant transformation of tumor cells, thus playing an anti-tumor role. and thus exerts anti-tumor effects. In addition, more research has been done on angiogenesis inhibitors in recent years. Avastin (bevacizumab) is a recombinant human anti-vascular growth factor (VEGF) monoclonal antibody, which is mainly used in the treatment of metastatic colorectal cancer, breast cancer, renal cancer and lung cancer.