Role of TKI for Metastatic Osteogenic Sarcoma.

Osteosarcomas (OS) belong to a large family of mesenchymal tumor entities which exhibit heterogenous histological, genetic, and molecular features. Current OS treatment regimen consists of the combination of surgery and intensive multi-agent chemotherapy. Ever since the introduction of chemotherapy, 5-year survival rate among OS patients has improved to 60-75%. However, 30-35% of OS patients are associated with pulmonary metastasis and relapse, which have significantly poor prognosis, with an overall 5-year survival rate of about 20%. The fact that OS are both rare forms of cancer and highly heterogeneous may explain why patients' survival has not improved in the past three decades, especially for metastatic/relapsed and unresectable osteosarcomas. Patients who experience relapse with metastatic disease have limited therapeutic options, often receiving additional cytotoxic therapy such as ifosfamide and etoposide and/or carboplatin or gemcitabine plus docetaxel. Novel precise OS-targeted thrapies are being developed with the hope of improving metastatic/relapsed OS prognosis. This review provides an overview of the most updated targeted therapies in relapsed/metastatic osteosarcoma and dicusses some clinical options in order to improve progression-free survival.