Osteosarcoma is a primary malignant tumour of the skeleton characterised by the direct formation of immature bone or osteoid tissue by the tumour cells. The classic osteosarcoma is a rare (0.2% of all malignant tumours) highly malignant tumour, with an estimated incidence of 3 cases/million population/year. Osteosarcoma arises predominantly in the long bones and rarely in the soft tissues. In about 75% of cases, patients with osteosarcoma are between 15–25 years of age. Male are more frequently affected than female (ration 1.5:1).
Osteosarcoma rarely occurs in patients younger than 6 years or older than 60 years. Tumours observed in older age usually develop secondary to Paget's disease, radiation or dedifferentiated chondrosarcomas. Drugs used in treatment of osteosarcoma are high-dose Methotrexate (HDMTX), Cisplatin (CDP), Adriamycin (ADM) and Ifosfamide (IF), generally used in combination. It is not clear if a 4-drugs combination (HDMTX, CDP, ADM, IF) offers advantages over a 3-drugs combination (HDTX, CDP, DM) treatment. In some centres, ADM and CDP are delivered intra-arterially.