What is osteosarcoma? Is it a “bone cancer”? From the patient’s point of view, osteosarcoma can be thought of as cancer of the bones. However, from a professional point of view, lesions that originate from epithelial tissues are called “cancer”, such as stomach cancer, liver cancer, skin cancer, etc.; lesions that originate from mesenchymal tissues are called “sarcoma”, including osteosarcoma, chondrosarcoma, synovial sarcoma, etc. In other words, there is a certain difference between “cancer” and “sarcoma”. In other words, there is a certain difference between “cancer” and “sarcoma”, but it is acceptable for people to call osteosarcoma as bone cancer. Is the incidence and mortality rate of osteosarcoma high? According to foreign literature, the incidence rates of osteosarcoma among blacks, Hispanics and whites are 6.8, 6.5 and 4.6 per million people per year, i.e., about 5-6 out of 1 million people will develop the disease each year. In contrast, osteosarcoma has the eighth highest incidence of malignancies in children. Osteosarcoma is the most common primary malignant tumor of orthopedics, accounting for 44% of all primary malignant tumors of orthopedics. Therefore, the incidence of osteosarcoma is relatively high. Osteosarcoma is a highly malignant tumor. Before the 1970s, the mortality rate of the disease reached over 90% and the five-year survival rate was less than 10%. Nowadays, with the continuous efforts of bone oncology specialists in research and with active and correct treatment, the five-year survival rate of patients is about 70%, and the treatment of osteosarcoma in our department has reached the top level in China and is leading in the world.