Axial skeletal osteosarcoma: a 25-year monoinstitutional experience in children and adolescents.

The survival of patients with axial skeletal or pelvic osteosarcoma (OS) remains poor, and the management of these patients is challenging. The object of this study is a cohort of unselected patients aged < 19 years with primary high-grade pelvic/axial OS. Patients were treated with high-dose methotrexate, doxorubicin, cisplatin, ifosfamide followed or preceded by local treatment (surgery and/or radiotherapy). Twenty patients aged 3-19 years were treated. Eight patients had pelvic OS, 8 axial OS and 4 mandible/maxilla OS. All patients received chemotherapy, after which necrosis was evaluable in 9 patients (≥ 90% in 3). Sixteen patients underwent surgery. Radiotherapy was administered to 8 patients (total dose 34-60 Gy). The median follow-up was 35 months (8-276), and the 5-year disease-free survival and overall survival rates were 37 and 40%, respectively. Six patients were alive at the time of this report: 2 with pelvic OS (both responded well to chemotherapy, one underwent hemipelvectomy and the other had non-radical surgery plus radiotherapy); 1 with axial and multicentric OS (with a good histological response and radical surgery); 3 with mandible/maxilla OS. Two patients died of secondary tumors (one bone and one breast cancer). It is worth noting that 4 patients had a p53 mutation: 1 is alive, 2 died of their OS, 1 of breast cancer. Adequacy of local treatment and pathological response influenced the prognosis for axial OS, which remained dismal. A high incidence of p53 mutation emerged in our series of patients.