Osteosarcoma
80% already have potential lung metastases at the time of initial presentation
Prior to the advent of adjuvant chemotherapy, the 5-year survival rate was only 10-20%, and 90% of patients died of lung metastases two years after surgery
Neoadjuvant chemotherapy has made a quantum leap in the treatment of osteosarcoma.
The significance of preoperative chemotherapy
Determine the sensitivity of tumors to chemotherapy and adjust the postoperative chemotherapy regimen for those who are not sensitive in order to improve tumor-free survival.
Considering from the perspective of tumor growth kinetics, tiny metastases are more sensitive to chemotherapy than large primary foci and smaller metastases. In order to avoid the delay of waiting for surgery and recovery period after surgery, and to more effectively eliminate metastases, control primary foci and cooperate with surgery, chemotherapy for osteosarcoma has been changed from simple postoperative chemotherapy to comprehensive chemotherapy before and after surgery.
Post-chemotherapy tumor necrosis is an important indicator to judge the prognosis. In patients with neoadjuvant chemotherapy for osteosarcoma of the limb, chemotherapy-induced necrosis, in addition to being associated with the long-term outcome of treatment, is also an independent factor affecting local recurrence.
Bacci et al. noted that in neoadjuvant chemotherapy treatment of osteosarcoma, the degree of necrosis in resected tumor specimens predicted disease-free survival (DFS), and the higher the degree of necrosis in the primary tumor, the higher the disease-free survival.
Diagnostic and treatment pathway for classic osteosarcoma
Sequential dosing
Drug administration
Combination of drugs
More than two
Pre-operative drug duration
2-3 months
4-6 cycles
Post-operative medication time
8-12 months
(12-18 cycles)
High-dose methotrexate with formyltetrahydrofolate relief (HD-MTX-CF-R) is one of the most important regimens of chemotherapy for osteosarcoma . It is chemotherapy administered to patients with dosages of MTX that are tens or hundreds of times higher than the conventional dosage to improve the efficacy. Safety can be guaranteed as long as it is coupled with blood concentration monitoring and laminar flow ward and hemodialysis conditions.