Bone cancer, whose scientific name is bone tumor, is insidious and dangerous, which not only causes severe pain but also often results in physical disability or even life threatening. Therefore, bone cancer seems to be synonymous with “amputation”. However, bone tumor has long been transformed from an incurable disease to a treatable disease, and most patients can keep their limbs. What are the categories of bone tumors? What are the most common ones? Bone tumors are generally divided into primary bone tumors and metastatic bone tumors. The proportion of the former is smaller, and the incidence rate in China is about 2~3/100,000 population, accounting for about 0.5%~1% of all malignant tumors. There are hundreds of primary bone tumors, among which osteosarcoma is the most common, accounting for about 35%, followed by chondrosarcoma (25%) and Ewing sarcoma (16%). The incidence of metastatic bone tumors is 30-40 times higher than that of primary ones, and nine out of ten clinically diagnosed bone tumors are metastases. Nowadays, the overall trend of malignant tumors is increasing, and metastatic bone tumors are also increasing, but in general, they are rare tumors in the whole tumor family. Is there any difference between benign and malignant bone tumors? What are the causes of bone tumors? There are benign and malignant bone tumors, and there are more benign tumors than malignant ones. Benign bone tumors include osteoma, giant cell tumor of bone, osteoid osteoma, osteochondroma and bone cyst. Among them, osteoid osteoma and osteochondroma are usually found in the lower limb bone stem of adolescents, which grow very slowly and can be “painless”, sometimes with pressure pain, and generally do not require surgery. Giant cell tumor of bone accounts for 4%-5% of primary bone tumors, which has potential malignant tendency and sometimes requires surgical treatment. The cause of primary bone tumors is still unclear, genetics is the most important risk factor and has little relationship with modern lifestyle. The adolescent period is in the stage of rapid growth and development, which is most vulnerable to stimulation and disturbance. The process of human growth and development is that old cells keep dying and new cells keep arising. If the new cells are stimulated by external stimulation or environmental disturbance in the process of arising, mutation and variation will occur in the process of growth and development. Metastatic bone tumors are often metastasized from tumors in lung, liver, prostate, breast and thyroid through blood circulation, with breast, lung and prostate cancers being the most common. Bone is the most popular site for cancer cells to metastasize except for lung and liver. At what age do bone tumors have a high incidence? For example, osteosarcoma is more common in adolescents and the epiphysis of long bones (near the knee joint and elbow joint); chondrosarcoma is more common in middle-aged people in their 40s and 50s and the end of long bones and pelvis; Ewing sarcoma is more common in children and adolescents and the pelvis and spine. Metastatic bone tumors mostly occur in middle-aged and elderly people in their fifties and sixties, and most commonly affect the spine, followed by the extremities. What are the typical disease signals of bone tumor? Bone joint pain, bony mass and dysfunction are the three main symptoms of bone tumor in the late stage, but in the early stage, there is no obvious symptom, and patients often suddenly feel a “bag” growing in knee joint and shoulder joint when changing clothes or taking a bath. Primary bone tumors mostly occur in adolescents with vigorous bone growth and are often accompanied by growing pains during the developmental period, which are easy to be ignored by children and parents. Pelvic tumors are also difficult to detect, and they often come to the clinic only after they have grown so large that they compress the nerves and cause severe pain or compress the bladder and rectum and cause difficulty in urination and defecation. Metastatic bone tumors often show pathological fractures, and also cause severe cancer pain due to nerve compression and paralysis due to spinal cord compression. In addition, when cancer cells metastasize to limb bones, local mass is often the first symptom, and when metastasized to trunk, pain is the first symptom. V. Can bone tumor be cured now? Does it require amputation? Thirty years ago, patients with bone tumors basically had to have their limbs amputated. What is more frustrating is that even the five-year survival rate of amputation patients is less than 20%, and 80% of patients will still die because the cancer cells metastasized to the lung and liver. As for osteosarcoma, which is a kind of dangerous tumor, it is basically a “death sentence”, and up to 90% of patients will eventually die. This is because bone tumors are less sensitive to chemotherapy drugs, for example, methotrexate is commonly used in hematology according to milligrams, while in orthopedics it is generally calculated in grams, and the risk of side effects is great with high doses. Radiotherapy is also ineffective for most bone tumors, only for Ewing sarcoma and a few metastatic bone tumors. Radiotherapy burns cartilage and skin very much, the skin will become hard, and the incision always grows badly after surgery, leading to higher infection rate. In recent years, there has been a fundamental change in the treatment of bone tumors, especially “neoadjuvant chemotherapy”, which makes limb preservation possible. In particular, neoadjuvant chemotherapy has made limb-preserving treatment possible. The specific practice is to administer one and a half months of high-dose chemotherapy before surgery to shrink the tumor and reduce intraoperative bleeding, and then add six months of chemotherapy after surgery. Today, the five-year survival rate for bone tumor treatment can reach 60% to 70%. It should be explained that the five-year survival rate is not equal to patients living only five years after surgery, but rather five years without recurrence. All in all, the survival rate of bone tumor treatment is higher than that of lung and liver cancer. With the improved survival rate, patients are more interested in limb preservation. The first step to limb preservation is to cut the tumor clean. Figuratively speaking, bone tumor is like the yolk inside an egg, we have to cut the egg and take out the yolk, but we cannot let the yolk (remaining cancer cells) have a trace of residue, so a thin layer of egg white has to cover it when we take it out. In clinical practice, taking out only the “yolk” is called marginal resection, while taking out even the “white” is called extensive resection. In order to preserve the limb, we must try to achieve wide resection in order to control the local recurrence rate to the prescribed level. 6. How to detect bone tumor early? Which high-risk groups need extra attention? People with family history of tumor should be alert when they have bone and joint pain. For example, many people have experienced back pain, which may be triggered by lumbar disc herniation, soft tissue injury, inflammation and so on. However, the pain of bone tumor is the most intense, characterized by pain that worsens at night, and the quieter it is, the more painful it is, and the pain is relieved when the activity is opened. Another example is teenage knee pain, children and parents may think it is growing pain caused by playing too much, sports injury or growing, but growing pain is usually paroxysmal, while bone tumor pain will continue to worsen, not relieved for a week or two, and may be accompanied by low fever, at this time, we must go to hospital to take a film.