Tumor bone metastasis is a serious complication in patients with advanced tumors. With the improvement of tumor efficacy and prolongation of survival period, the incidence of metastatic bone tumors has increased significantly in recent years, and according to statistics, the incidence of metastatic bone tumors accounts for about 15-20% of the whole body metastases, second only to lung metastasis and liver metastasis, and occupies the third place, about 70% of the patients with pro-osteopathy tumors, such as breast cancer, prostate cancer, etc., suffer from bone metastasis in their natural disease process. About 70% of patients with breast cancer, prostate cancer and other bone-friendly tumors have bone metastasis during the natural course of the disease. Bone metastasis is often the first station of distant metastasis of breast cancer, and the bones of prostate cancer patients are often the first part of metastasis or recurrence, and about 46% of the recurrence of lung cancer patients show bone metastasis, and about 90% of the patients with bone metastasis are suffering from pain, of which about 73% of the patients with bone metastasis of breast cancer, prostate cancer and lung cancer. Cancer bone metastasis is one of the main causes of cancer pain, and the pathological fracture, spinal cord compression, hypercalcemia and bone marrow failure it causes accelerate the progression of the disease and seriously affect the quality of patient’s survival. With the change of people’s concept of treating bone metastasis and the improvement of treatment methods, appropriate treatment can reduce the risk of bone-related events to relieve bone pain, restore normal function and improve the quality of life. Quality of life. 1.1 Chemotherapy, endocrine therapy and molecular targeted therapy Systemic therapy mainly includes combined chemotherapy, endocrine therapy, nuclide therapy and traditional Chinese medicine for primary tumor, bone metastasis should be regarded as systemic disease, and effective systemic therapy can eradicate the cause of bone metastasis and other metastatic foci of malignant tumors in some patients, and it has been proved that chemotherapy is useful for bone metastasis of breast cancer, small cell lung cancer, lymphoma and germ cell tumor, and germ cell tumors. Regardless of whether the primary tumor is resected or recurrent, chemotherapeutic agents that are effective for the primary tumor can be combined to eliminate subclinical foci and microscopic metastases and reduce the metastatic rate. Systemic chemotherapy has been shown to prolong the survival of patients with bone metastases from non-small cell lung cancer and small cell lung cancer, and combination chemotherapy with platinum and newer drugs are recommended for patients with better physical status. Breast cancer is often sensitive to combination chemotherapy and endocrine therapy. For postmenopausal patients with positive estrogen and progesterone receptors, endocrine therapy is also a very important treatment, which can effectively control the progression of the disease and relieve cancer pain. The emergence of new drugs has brought light to patients with advanced tumors. In 2004, pemetrexed was approved by the US FDA as a second-line treatment for locally advanced or metastatic non-small cell lung cancer, and fossella et al. found that the efficacy of pemetrexed in treating non-small cell lung cancer was significantly better than that of optimal supportive therapy or placebo treatment, which further affirmed the value of pemetrexed in the treatment of advanced non-small cell lung cancer. This result further affirms the value of pemetrexed in the treatment of advanced non-small cell lung cancer. Bone is the most common target organ for distant metastasis of prostate cancer, and chemotherapy was once considered ineffective for androgen-independent prostate cancer. In recent years, new progress has been made in the research of chemotherapy, and paclitaxel analogues, especially doxorubicin, have shown certain advantages in the treatment, and the anti-tumor mechanism of doxorubicin mainly lies in the inhibition of depolymerization of microtubules and the inhibition of oncogenes bcl-2 and bcl-xl expression, and the recent studies have shown that doxorubicin can be used to treat advanced non-small-cell lung cancer. Studies have shown that doxorubicin can significantly prolong life and reduce symptoms, and control prostate-specific antigen, doxorubicin is the first chemotherapeutic drug that can significantly prolong the survival of patients with androgen-naïve prostate cancer, and at present, the U.S. Food and Drug Administration has approved doxorubicin in combination with prednisone for the comprehensive treatment of advanced androgen-naïve prostate cancer. Endocrine therapy is an important part of the comprehensive treatment of prostate cancer, which can be treated with surgical removal of the testes or chemical de-escalation or the use of anti-androgen drugs. Molecular targeted therapy is to select the specific molecular target of cancer cells and apply the drugs against the target for treatment, which can achieve obvious curative effect while avoiding the harm to normal cells, and now there are many kinds of targeted therapeutic drugs approved by the U.S. Food and Drug Administration (FDA). Bevacizumab (bevacizumab) is a humanized monoclonal antibody against VEGF-A. Hurwitz et al. reported the results of a phase III clinical trial in patients with primary-treated metastatic colon cancer (CRC), with significant advantages in terms of time to tumor remission and survival. Sorafenib is a multi-targeted biologically targeted new drug, approved by the US FDA in 2005 for the treatment of advanced renal cell carcinoma, preclinical studies and clinical trials suggest that sorafenib and a wide range of anti-tumor effects, in a randomized non-continuous Ⅱ of its clinical trials initially observed that sorafenib treatment of renal cell carcinoma has a significant efficacy [9]. 1.2 Radionuclide therapy Radionuclides can effectively relieve bone pain caused by bone metastases, especially when multiple lesions need to be treated, these drugs are 89 strontium, 153 samarium, and 32 phosphorus [11], and most of the experimental results of their drugs come from this breast cancer and prostate cancer. 89sr is similar to calcium and is mainly distributed in the bone tissues, especially in the areas where osteoblasts are active. 89 strontium has a half-life of 4-5 days, and a single dose of 148MBB has a significant effect. days, a single dose of 148 MBq administered by routes other than oral, pain is relieved within 7 to 12 hours, and efficacy lasts an average of 6 months, so it is recommended in patients with moderate pain with a similar expected survival.The mechanism by which strontium 89 relieves pain in bone metastases is not well understood, but is related to the amount of resorption by the bone and the tumor tissues, and different studies have shown varying rates of efficiency for strontium 89, with some studies have shown no benefit for pain improvement, while others have shown a 77% response rate, with the known associated toxicity being temporary bone marrow suppression. Samarium 153 consists of an ethylenediamine tetramethylene phosphonic acid complex (153SMI-EDTMP), which, like 89Sr, is enriched in association with osteogenic activity. 153SMI-EDTMP has a half-life of 1-9 days and is usually administered intravenously, and is characterized by low toxicity, making it the most widely used nuclidinium therapeutic drug in the U.S. for pain relief, with 83% of patients with bone metastases having Pain relief. 1.2 Bisphosphonates should be transported Bisphosphonates can be adsorbed on the combination of minerals, interfere with the attachment of osteoclasts, make the ultrastructure and morphology of mature osteoclasts undergo minor changes, thus inducing apoptosis of osteoclasts, effectively inhibiting osteoclasts from resorbing and resorbing bone, and at the same time, it can affect the adhesion, invasion, and proliferation of tumor cells, which enhances the effect of cytotoxic drugs in a synergistic manner. Mcc0rmack et al. concluded that ibandronic acid can inhibit osteoclast-mediated bone resorption, effectively prevent the occurrence of bone-related events to improve the quality of life of patients with breast cancer bone metastases, and that it is equally effective when administered orally and intravenously. [Body et al [13] reported that oral and intravenous ibandronate had the effect of reducing bone-related events and prolonging the time to the appearance of the first bone-related event. Zoledronic acid significantly reduced the incidence of bone metastasis-related events in prostate cancer and improved survival time for up to 24 months [14]. Zoledronic acid is effective in breast cancer, prostate cancer, metastatic lung cancer, renal cell carcinoma and other solid tumors, and has been proven to be effective for osteolytic metastases in addition to mixed and osteogenic metastases with significant clinical efficacy. 2.1 Radiation therapy: Radiation therapy is mostly used for the treatment of pain in bone metastases, and recent studies have shown that a single dose of irradiation can provide long-term relief of pain after bone metastases [15], and the specific mechanism of pain relief is not very clear, and one of the mechanisms is through a direct effect on tumor cells. External irradiation is an important palliative treatment for patients with bone metastases, and it is very effective in relieving bone pain, as pain relief can be achieved within 48 hours of the start of radiotherapy, and overall, 70-75% of patients have at least partial relief of their pain after treatment, and 40-60% have complete relief, and external irradiation is the most effective means of relieving bone pain if the disease is confined and there is a condition for high-dose radiotherapy to be given to a single lesion. Many studies have attempted to determine the optimal dose fractionation that achieves the most effective treatment while minimizing side effects. Typical radiotherapy doses include 800 cGy/10 treatments or 2000 cGy/5 treatments or 3000 cGy/10 treatments. None of the dose splits has shown an advantage in lung cancer, perhaps because there is so much variation between patients and between treatments, and many factors including extent of disease, comorbidities, patient behavioral status, dose, initial size of the lesion, and number of treatments potentially influence efficacy. In general, higher split doses seem to provide better pain relief and longer periods of remission in patients with lung cancer. Hemifractional radiotherapy and wide-field radiotherapy can be used for multiple bone metastases and also play a role. 2.2 Surgery Surgery is another option for relieving pain and restoring organ function in patients with bone metastases. Complications of bone metastases that require surgical intervention are mainly neurological symptoms caused by pathologic fractures or spinal cord compression. Surgical management of pathological fractures is mainly: internal fixation, spinal canal decompression, osteosynthesis, partial resection, joint fusion/replacement, and repair and replacement, and the purpose of these surgeries is to restore the strength of the bone, alleviate pain, and enable the bone to bear weight after surgery. The consequences of pathologic fractures are extremely serious, so there is a greater need to anticipate the risk of fracture at the metastatic site and to perform prophylactic surgery; intervening before a fracture occurs is a much easier and safer strategy, and the patient recovers more quickly in this scenario. 2.2.1 Surgical treatment of long bone metastases Not all bone metastases require surgical treatment; the size and location of the lesion as well as the patient’s general condition and life expectancy are factors that should be taken into account when determining the optimal treatment plan. Metastases that accumulate less than 50% of the bone cortex or those that accumulate non-weight-bearing bone (e.g., the fibula) may not require surgical treatment, but only close follow-up. Also patients with severe comorbidities or short life expectancy are not candidates for surgical treatment. The Mirels scoring system has been evaluated for the need for surgical treatment, with a score of ≤7 the likelihood of fracture is low and non-surgical treatment is feasible, if the score is ≥8 the likelihood of fracture is high and prophylactic fixation should be performed, but this scoring method does not take into account the patient’s functional needs, life expectancy, and the patient’s pre-existing risk of osteoporosis. katakami concluded that bone metastases from lung cancer Prophylactic internal fixation in patients is used for patients with 30-50% cortical destruction of long bones, pain that persists after radiotherapy, and an expected survival of greater than 3 months. The choice of surgical method, for pathological fractures of extremity backbone, the most appropriate method is to use interlocking intramedullary pin internal fixation, biomechanical confirmation of interlocking intramedullary nails through the axial fixation and fixation of the arm is long, and compared with the steel plate has a good compression and torsion, which is conducive to early weight-bearing, and can be early out of bed after surgery, femoral neck fracture can be used with a long-handled femoral prosthesis or a total hip replacement, femur rotary area fracture Fractures of the femoral rotor area can be reconstructed with a long-stemmed femoral prosthesis or proximal femoral replacement. The pointers for prosthesis replacement in patients with bone metastases include extensive osteolytic lesions, pathological fractures with substantial bone loss, and patients who need revision surgery due to failure of internal fixation or disease progression. Bone metastases with pathologic fractures adjacent to the articular region are currently unable to achieve strong and firm internal fixation using any internal fixation, and studies have confirmed that the application of tumor-based artificial joints can reconstruct large bone defects after complete or partial resection of the metastases [20]; the proximal femur, a frequent site of bone metastases, also often suffers from pathologic fractures, and pain due to pathologic fractures is an indication for surgical procedures, and resection of the tumor segments and Subsequent arthroplasty is the most effective, Chrobok et al. treated patients with pathologic fractures of the proximal femur with Austin-moore artificial hip replacement, and 67% of the patients had good results based on Merle’s score. Whether it is necessary to scrape the metastatic lesions while performing immobilization or prosthetic reconstruction lacks definite evidence to support, but there are theoretical advantages for some patients to be treated in this way, for example, renal cell carcinoma is ineffective for local adjuvant therapy such as radiotherapy, and its metastatic foci have been recently reported to be applied with wide excision or intra-lesional scraping in relatively non-operative patients, and the combination of aggressive local control measures and adjuvant therapy can clearly improve the survival rate. clearly improve survival, but there was no difference in survival between patients with wide resection and intra-lesional curettage. The risk of using a long-stemmed prosthesis (250-350 cm) is cardiopulmonary damage due to thromboembolism during femoral marrow cavity preparation or cement injection. Recent research material has shown that cardiopulmonary complications associated with long-handled prostheses can be greatly reduced if appropriate precautions are applied. 2.2.2 Pelvic Metastases Because of the complexity and uniqueness of the pelvis, it is a great challenge for tumor resection and postoperative reconstruction. Surgery is not necessary for metastases that are properly controlled by radiotherapy and systemic systemic therapy, but it is required for possible or already existing metastases that involve the acetabulum and sacroiliac joints and affect the patient’s walking, because pelvic surgery is long, bleeding and dangerous, and it is expected that the patient can survive for more than 4 months before surgical treatment is performed. For metastases in the acetabulum, cemented total hip arthroplasty is usually used, combined with the use of Stippling pins, bone cement and acetabular strengthening cup reconstruction. 2.2.3 Spinal metastases Surgery is one of the main treatments for spinal metastases. The goals of surgery are to relieve pain, decompress the spinal cord, restore or preserve neurologic function, reestablish spinal stability, and improve quality of life. Ghogawala et al. formulated an intuitive surgical criteria according to the clinical manifestations of MST patients: ① pain or obvious spinal instability due to structural damage, compression; ② obvious symptomatic mechanical compression of spinal cord nerves; ③ progressive spinal cord nerve damage caused by intravertebral space occupation or other compression; ④ the primary tumor is not known, but there is an obvious metastatic lesion in spine; ⑤ metastatic lesion of spine ineffective in radiotherapy; ⑥ metastatic lesion in radiotherapy; and ⑥ metastatic lesion in the spinal cord is not known in the spinal canal, but there are obvious metastatic foci in spine. The primary tumor is unknown, but there are obvious metastatic lesions in the spine; ⑤ metastatic lesions in the spine that are not effective for radiotherapy; ⑥ pain and neurological symptoms are obviously aggravated during or after radiotherapy. The choice of surgical access requires good exposure and maneuvering space, which is conducive to tumor resection and stability reconstruction, and can be divided into anterior, posterior and combined anterior and posterior approaches.Ernstberger et al.[28] reviewed 24 cases of laminectomy and vertebral body replacement in MST, and found that 85% of the postoperative pain was relieved, and 57.1% of the patients’ neurological symptoms were alleviated, with an average survival rate of 15.6 months, and concluded that vertebral body replacement could directly improve the pain and neurological symptoms. The average survival of all patients was 15.6 months. It is believed that vertebral body replacement can directly restore spinal stability and reduce tumor-related symptoms. Guo et al[29] performed anterior laminectomy for spinal structural stability reconstruction in 93 patients with MST, 87 patients (93.5%) had pain relief, 47 patients had neurological improvement, and the one-year survival rate was 85%. The posterior route is simple, with little tissue damage and little effect on spinal stability. Laminectomy with internal fixation was used to treat metastatic cancer of the spine, and neurological function was improved after the operation, and patients’ pain was significantly relieved. Since the spinal cord compression mainly comes from the anterior vertebral body, it is difficult to resect the vertebral body in the posterior route, and the long-term efficacy is poor. For multiple spinal metastases, the tumor involves the three column structures of the spine, and it is difficult to fully resect the tumor by anterior surgery, it is feasible to use posterior lateral approach, segmental internal fixation, and if necessary, decompression is relieved by one side transverse process and pedicle root approach, although there are certain limitations, the decompression effect in the short term is exact and reliable. Compared with simple anterior or posterior surgery, especially for patients with tumors involving vertebral bodies and accessories of the spine, combined anterior and posterior approach can achieve complete resection of the tumor, complete decompression of the spinal canal and restoration of spinal stability.Fourney et al[30] achieved good results with combined anterior and posterior approach for 26 patients with metastatic cancer of the spine. Most of MST is located in the vertebral body, and spinal stability needs to be reconstructed after tumor resection. Usually, vertebral defects are reconstructed with autologous/allogeneic bone, bone cement, and/or Cage (artificial vertebral body), and Liu et al. believed that anterior cervical reconstruction of structure and stability is an effective end of the treatment of MST.Tao et al.[32] surgically treated 63 patients with MST, and 41 patients were treated with anterior total vertebral resection and decompression of total vertebral body or semi-vertebral body, reconstruction of internal fixation, and 8 cases of anterior and posterior combined approach were treated. In the first 63 cases of MST, 41 cases of total or half vertebral body resection and decompression with structural reconstruction and internal fixation, 8 cases of laminectomy and internal fixation, and 14 cases of total vertebral body resection and decompression with structural stability reconstruction by single-segment anterior and posterior combined approach, the spine was stabilized by radiological assessment in the postoperative period of more than 6 months, and the pain was relieved in 57 cases with improvement in the quality of life, and neurological function was improved in 41 cases with no serious complication. Conventional post-laminectomy defects are filled by bone cement, which can obtain both temporal stability and prevent tumor erosion, especially suitable for patients with a life expectancy of no more than 6 months, while wire or screw cement can also be applied to improve stability with adjacent vertebrae [33], for anterior reconstruction with a life expectancy of more than 6 months, direct interbody fusion and Cage can be used [34], and for posterior reconstruction most scholars favor the endofacial fixation tethered approach. Malignant tumors have a high rate of spinal metastasis, and specific treatment options should be based on evaluation criteria and surgical pointers.Ecker et al. concluded that the optimal treatment plan for patients with MST should be selected based on the assessment of neurological function, anatomical site, general health status, age, and quality of life. Tumor treatment requires close collaboration of multiple disciplines, and the treatment of bone metastases is an important part of comprehensive tumor treatment, which should not only focus on the treatment of bone metastases but neglect the treatment of primary tumor, and the efficacy of comprehensive treatment is better than single method treatment. The treatment of lung cancer bone metastasis patients requires comprehensive treatment such as radiotherapy, surgery, chemotherapy, analgesic treatment, bisphosphonate treatment, etc. Prostate cancer is most prone to bone metastasis, in addition to palliative treatment at the appropriate time applying radiotherapy, surgery can prolong the life of patients, and the combination of chemotherapy, endocrine therapy, new anticancer drugs, application of bisphosphonates, and strontium can further increase the therapeutic efficacy. Adhere to the principle of moderate treatment, for patients with less malignant degree, moderate differentiation or single bone metastases with long expected survival time, more active treatment means can be adopted, such as radical surgical treatment, while for patients with poorer prognosis and multiple metastases, moderate treatment should be based on the principle of reducing patient’s pain and improving the quality of survival, and the symptomatic treatment mainly focusing on nutritional support and effective analgesia. What is more important in the treatment of bone metastases is that clinicians should reasonably choose different therapeutic arms such as surgery, chemotherapy, radiotherapy, nuclide therapy, bisphosphonate drugs, analgesic therapy and so on according to the specific conditions of the patients, so as to minimize the pain of the patients, improve the quality of life and prolong the survival period. The principle of individualization should be adhered to in the choice of treatment methods.