Is chemotherapy effective for osteosarcoma? A large number of clinical data show that a large amount of tumor necrosis can be seen on postoperative pathology in osteosarcoma, with many specimens having a tumor necrosis rate of 90% or more. It is due to the widespread use of chemotherapy that the survival rate of osteosarcoma has increased from less than 20% to the current 50-80%, and the limb preservation rate has reached nearly 90%. Chemotherapy for osteosarcoma therefore occupies an important place in treatment and has become the standard of care. Is high-dose chemotherapy for osteosarcoma dangerous? Whether preoperatively or postoperatively, high-dose strong chemotherapy is used for osteosarcoma, such as high-dose methotrexate, cisplatin, anthracyclines, isocyclophosphamide, etc. The side effects of chemotherapy with these drugs are strong, such as severe bone marrow suppression combined with infection, bleeding, gastrointestinal reactions, damage to multiple organ functions such as heart, liver and kidney, etc. Patients will suffer greater pain and burden physically, mentally and economically. Each drug has different characteristics in use, such as hydration, alkalinization, detoxification, and supportive therapy, etc. It is important to receive chemotherapy under the guidance of an experienced physician to minimize the side effects and risks that patients experience. Why should preoperative neoadjuvant chemotherapy be implemented? Pre-operative neoadjuvant chemotherapy is a prerequisite for limb-preserving treatment and has guiding significance for post-operative chemotherapy. (a) Effective neoadjuvant chemotherapy can necrotize a large number of tumor cells and shrink the tumor, which obviously improves the rate of limb preservation and reduces the chance of postoperative recurrence; (b) It can control the micro-metastases and blood-type dissemination and reduce the chance of metastasis; (c) The tumor necrosis rate is used to evaluate the sensitivity of tumor to chemotherapy drugs, which helps the selection of postoperative chemotherapy regimen; (d) It reduces the activity of tumor cells and reduces the chance of tumor cell spread during surgery (e) The risk of neoadjuvant chemotherapy is that for patients with ineffective chemotherapy, it can increase the possibility of tumor progression and metastasis during chemotherapy. Do I still need chemotherapy after surgery? Adjuvant chemotherapy after surgery is necessary to remove any microscopic lesions that may remain in the body and reduce the chance of recurrence and metastasis. If the pathology shows more than 90% tumor necrosis, the preoperative chemotherapy regimen can still be used after surgery, but in cases less than 90%, the regimen needs to be changed. Is radiotherapy effective for osteosarcoma? The literature reports that normal doses of external irradiation have limited effect on osteosarcoma, but some results have been reported with intraoperative megadose radiotherapy without ex vivo inactivation of the tumor segment bone. Normal-dose radiotherapy can be considered for the treatment of metastases or palliative treatment for symptom relief. In conclusion, osteosarcoma is a common malignant tumor in children and adolescents with a high degree of malignancy, but if detected early and treated with standardized comprehensive treatment, most patients can not only survive for a long time but also may retain their limbs to obtain a better quality of life. Regardless of whether there is trauma or not, parents should seek medical attention as soon as they find pain and swelling in their children’s limbs to facilitate early detection of osteosarcoma. Because the treatment process of osteosarcoma is complicated, limb preservation surgery is difficult, and irregular treatment can affect the limb preservation rate and survival rate of patients. Therefore, once osteosarcoma is suspected, one should visit a hospital with treatment experience to receive standardized diagnosis and treatment.