Treatment of bone metastases from kidney cancer should be a combination of mainly medical treatment. Removal of the primary renal lesion may improve the efficacy of interferon (IFN)-α or (and) interleukin (IL)-2 in the treatment of metastatic renal cancer. For isolated bone metastases arising after resection of concomitant renal cancer or renal primary lesions, surgical treatment can be chosen if the patient is in good physical condition and has a low prognostic risk factor score for metastatic renal cancer, the latter can also be performed simultaneously with renal surgery or staged according to the patient’s physical condition. For patients with pathological fracture of bone metastasis of kidney cancer or with fracture risk of weight-bearing bone, surgical treatment should be preferred if the patient is in good physical condition. Previously, high-dose IL-2, IFN-α, gemcitabine, capecitabine, fluorouracil deoxynucleoside, and 5-Fu were used as first-line treatment regimens for metastatic kidney cancer, and adriamycin was only used as first-line treatment for patients with renal non-clear cell carcinoma with sarcomatoid differentiation in the cancerous tissue. since 2006, the NCCN and EAU have included molecularly targeted therapeutic agents (sorafenib, sunitinib Temsirolimus, bevacizumab combined with IFN-α) as the first and second-line treatment for metastatic renal cancer (level of evidence Ib). （In 2007, Escudier et al. reported the phase III global evaluation of treatment approaches in renal cancer (mRCC) with sorafenib in the metastatic renal cell carcinoma (mRCC). The interim results of the global evaluation trial (TARGETs) showed that sorafenib was 10% effective in treating metastatic renal clear cell carcinoma that had failed primary systemic anti-cancer therapy, with progression-free survival (PFS) of 24 weeks, a 1-fold increase compared to the placebo control group. Tumor lesions remained stable in 74% of patients, and the disease control rate [(complete response (CR) + partial responses (PR) + stable disease (SD)] was 84%. Between April 2006 and August 2007, Academician Sun Yan led a study to analyze the safety and efficacy of sorafenib in Chinese patients with advanced renal cell carcinoma, which was an open, multicenter, uncontrolled clinical study. 62 patients with advanced renal cancer were enrolled, 5 were withdrawn due to toxic side effects, and 57 patients were evaluable. The median age of the entire group was 53 years, 43 men received sorafenib 400 mg twice daily for at least 2 months. The results were 1 CR (1.75%), 11 PR (19.3%), 36 SD (63.16%), with a disease control rate of 84.21%, median PFS time of 41 weeks, and median overall survival (OS) not achieved. hypertension (12.9%), leukopenia (3.2%), and hyperuricemia (9.7%). The disease control rate (CR+PR+SD) was consistent with that reported in a phase III randomized double-blind controlled study of sorafenib abroad (TARGET trial). The recommended dosage of sorafenib is 400 mg bid/day (recommendation grade B). 2) Sunitinib Sunitinib has an efficiency of 24.8% and a PFS of 11.2 months in the treatment of metastatic renal clear cell carcinoma, which is significantly better than IFN-α. 3) Temsirolimus Temsirolimus has an efficiency of 9% and a disease control rate of 49% in the treatment of advanced patients with poor prognosis, and significantly prolongs overall survival compared with the IFN-α group (10.9 months vs. 7.3 months). (4) Bevacizumab combined with IFN-α Bevacizumab combined with IFN-α for advanced renal clear cell carcinoma had an effective rate of 30.6% and significantly prolonged PFS compared with the IFN-α monotherapy group (10.2 Vs 5.4 months). 2. Cytokine therapy 1) IL-2 IL-2 can be used as the first-line treatment for metastatic clear cell carcinoma (level of evidence Ib). Between July 2004 and June 2006, an open, multicenter, uncontrolled clinical study was conducted in China on the efficacy and safety of single-agent recombinant humanized IL-2 (Proleukin) administered subcutaneously for the treatment of metastatic renal cancer. Forty-one patients with pathologically confirmed metastatic kidney cancer were enrolled. The patients received IL-2, 9 million IU, once every 12 hours on days 1 to 5 in the first week, and IL-2, 9 million IU, once every 12 hours on days 1 to 2 in the second three weeks, and IL-2, 9 million IU, once daily on days 3 to 5 in the third week; the treatment was discontinued in the fifth week. A total of 2-4 cycles. 5 cases were discharged from the group due to toxic side effects, 36 cases could be evaluated for objective efficacy, 0 CR, 7 PR (19.4%), 16 SD (44.4%), 13 PD (36.1%), disease control rate 63.9%, median PFS not yet reached but more than 12 months. Serious adverse reactions (≥ grade 3) were rare, mainly manifested as mild to moderate adverse reactions of grade 1 to 2 in multiple systems. The results of the study showed that the efficacy of low to moderate dose IL-2 in the treatment of metastatic kidney cancer in Chinese is the same as that reported abroad. The recommended dose of IL-2: 18 million IU/day, subcutaneous injection, 5 days/week for 5-8 weeks (recommended level B). IFN-α IFN-α is effective in patients with metastatic renal clear cell carcinoma with low and intermediate risk factors (level of evidence Ⅰb). Combined with the domestic situation in China, IFN-α is recommended as the first-line treatment option for patients with metastatic renal clear cell carcinoma with low- or intermediate-risk factors (recommendation level A). The recommended therapeutic dose of IFN-α: 9 million IU/dose, intramuscular or subcutaneous injection, 3 times/week, 12 weeks as a course of treatment. IFN-α can also be used in stepwise increments, with 3 million IU per dose in week 1, 6 million IU per dose in week 2, and 9 million IU per dose in week 3. IFN-α has an efficiency of 15% in the treatment of metastatic RCC, with a median survival time of 8.5 to 13 months. 3. Chemotherapy Chemotherapy is mainly used as the first-line treatment option for patients with metastatic non-clear cell carcinoma (level of evidence III). The main chemotherapeutic agents used to treat mRCC are gemcitabine, fluorouracil, capecitabine and cisplatin. Gemcitabine combined with fluorouracil or capecitabine is mainly used for clear cell-dominant mRCC; gemcitabine combined with cisplatin is mainly used for non-clear cell-dominant mRCC; if the tumor tissue contains sarcomatoid differentiation components, adriamycin can be combined in the chemotherapy regimen. The efficiency of chemotherapy is about 10%-15%. Chemotherapy combined with IFN-α or (and) IL-2 has also not shown an advantage. （The recommended bisphosphonates include pamidronate disodium and zoledronic acid, but the efficacy of zoledronic acid is better than that of pamidronate disodium. (iii) Surgical treatment of RCC bone metastases are mostly osteolytic and prone to complications such as pathological fracture or spinal cord compression,. The most effective treatment for bone metastases is to apply surgical methods to remove the metastases. For patients with resectable primary lesions or resected primary lesions with a single bone metastasis (not combined with other metastatic lesions), aggressive surgical treatment should be performed. Patients with bone metastases with weight-bearing bone at risk of fracture should undergo prophylactic internal fixation to avoid fracture. Patients who have developed pathological fractures or compression symptoms of the spinal cord should be first selected for orthopedic surgery if the following three conditions are met: (1) the patient’s survival is expected to be >3 months; (2) the physical status is good; and (3) the postoperative period can improve the patient’s quality of life and help to receive radiotherapy, chemotherapy and care. Surgical procedures targeting bone metastases are mostly palliative treatments, mainly used to treat and prevent pathological fractures and relieve spinal cord compression. It can achieve the purpose of relieving symptoms, avoiding nerve damage or even paraplegia, preserving or restoring limb function and bladder and other functions, and improving the quality of life. Surgical resection of isolated bone metastases may prolong the survival of some patients. (iv) Local radiotherapy External radiation radiotherapy mainly treats single bone metastases and multiple bone metastases with obvious painful sites, with the main purpose of relieving bone pain, restoring function and preventing further development of local lesions leading to pathological fractures and spinal cord compression. At present, it is believed that local radiotherapy is an effective method for local pain relief treatment of kidney cancer bone metastases, which can relieve the pain of 70% of patients. (v) Drug analgesic treatment is one of the main methods to relieve the pain of kidney cancer bone metastasis. The treatment of analgesic drugs should follow the WHO basic principles of cancer treatment, and analgesic drugs can be combined with bisphosphonates or radiotherapy to relieve the pain of patients with kidney cancer bone metastases to the maximum extent.