Low back and leg pain is one of the common reasons for middle-aged and elderly people to visit the hospital. As we age, degenerative changes in bones occur, leading to osteophytes or osteoporosis, which is the most common cause of back and leg pain in middle-aged and elderly people. More than 90% of thoracic and lumbar spine tumors are metastatic tumors, and most patients only draw attention when the tumors metastasize to the bones and produce obvious pain; many patients often do not pay enough attention to this pain at the beginning, and often treat this pain as common lumbar pain or lumbar disc herniation, sciatica, etc., thus delaying the treatment. On the other hand, doctors tend to neglect to investigate the rare causes of low back and leg pain, which leads to misdiagnosis and mistreatment. Differentiation between low back pain and pain caused by metastatic cancer of thoracic and lumbar vertebrae Low back pain is mainly caused by acute lumbar sprain or leg muscle strain, lumbosacral strain, skeletal strain, lumbar disc herniation, etc. Most of the causes are traumatic (sprain) injury, weight-bearing, cold and dampness; restriction of lumbar or spinal activities; increased pain from sitting or bending over for a long period of time; stiffness of the lumbar and leg in the morning, which can be relieved after activities; X-ray examination can reveal Bone destruction, fractures, and some may show osteophytes; patients with lumbar disc herniation can be clearly diagnosed and localized by CT or magnetic resonance imaging (MRI). It can also be differentiated from intravertebral tumor. The characteristics of cancer pain are different; firstly, patients have a history of cancer tumor, and pain is the main symptom of patients with skeletal metastatic cancer, and most patients complain that it is mainly at night. For example, the radiating pain from metastatic cancer of thoracic vertebral segment is like a band around the thoracic back, feeling like the chest is strangled by a bundle of cloth; while the pain from metastatic cancer of lumbar vertebrae radiates to the sacrum, anterior superior skeletal spine or groin on one or both sides. If the cancer cells invade the sacrum, pain in the lower back or sacrococcygeal area may also occur, and it may also radiate to the perineum or around the anus. Key points to note in screening tumor bone metastasis It is because the manifestation of bone metastasis tumor is not characteristic, and the first manifestation is only unexplained lumbar pain, greedy blood, recurrent lung infection, or even unexplained fast blood sedimentation and proteinuria found during health checkup, etc., coupled with the lack of awareness and vigilance of clinicians about this disease, resulting in a high misdiagnosis rate of this disease, which is often misdiagnosed as lumbar degenerative changes, lumbar muscle strain, Chronic nephritis, nutritional anemia, senile pneumonia, etc. are often misdiagnosed as degenerative changes of the lumbar spine, lumbar muscle strain, chronic nephritis. When middle-aged and elderly people have the above-mentioned manifestations for unknown reasons, they should consider the possibility of this disease and go to the hospital as soon as possible for necessary examinations, such as blood biochemistry, immunoglobulin determination, bone marrow aspiration and bone imaging, etc., in order to clarify the diagnosis and treat the disease as soon as possible. To detect cancer bone metastasis as early as possible, there are mainly the following clinical examination methods: ① It is difficult to diagnose by early X-ray plain film, which can be observed only when the bone destruction of the spine reaches more than 1 cm and the bone decalcification reaches 50%-70%; ② Isotope bone scan is one of the highly sensitive methods to check whether the bone has been invaded by cancer, and some studies have shown that it can be detected 6 months earlier than X-ray examination; ③ Bone metastasis can be detected by CT scan. For example, malignant tumors from lung, kidney and gastrointestinal tract are often osteolytic; while malignant tumors from breast and prostate are mostly osteogenic; ④ Magnetic resonance examination is more than 90% accurate in detecting bone metastases, and through certain examination methods, spinal bones, spinal cord, nerves and soft tissues can be observed. ⑤ PET/CT (electron emission computed tomography) examination can detect microscopic lesions that are difficult to be detected by general examination; if bone aspiration biopsy can be done, the pathological type of bone metastases can be clarified, which is very important for guiding treatment. Treatment related to tumor bone metastasis Although cancer has developed to the stage of bone metastasis, the opportunity of early treatment has been missed; however, after combined chemotherapy or endocrine therapy, immunotherapy, nuclear therapy and Chinese herbal medicine, many patients’ pain and other symptoms can be significantly relieved. For example, systemic treatment: It mainly includes combined chemotherapy or immunotherapy, nuclear therapy and Chinese herbal medicine for the primary tumor to contain the tumor development at the source. Radionuclide therapy: using osteophilic radiopharmaceuticals for in vivo radiation treatment of bone metastases, it can effectively reduce pain, decrease the dosage of painkillers and improve the quality of life. Bisphosphonates treatment: these drugs have high affinity with bone and are effective in both osteolytic mixed and osteogenic metastases, it can inhibit bone destruction and induce apoptosis of osteoclastic cancer cells, and it has obvious pain relief; it has light damage to kidney function and is a common drug for treating bone metastases. Radiation therapy (radiotherapy), commonly known as “electrotherapy”, is effective in relieving bone pain, reducing the occurrence of pathological fracture and alleviating the compression of bone tumor on spinal cord. 70% to 100% of patients can have their bone pain reduced or disappeared. Surgical treatment: Surgery can directly remove the metastatic tumor, remove the cause of bone pain, reduce the pressure of tumor on spinal cord and improve the survival quality of patients. If surgical treatment can be combined with chemotherapy and radiotherapy, it will have a significant effect on the life expectancy and quality of life of patients.