Metastatic osteosarcoma at diagnosis: prognostic factors and long-term outcome--the French pediatric experience.

BACKGROUND: The objective of this report was to estimate long-term outcome and prognostic factors in children and adolescents who presented with metastatic osteosarcoma at diagnosis. Patients were treated in six French pediatric oncology centers with surgery and multiagent chemotherapy, mainly with high-dose methotrexate. Their medical records were reviewed retrospectively.

METHODS: The medical records of patients who were treated for metastatic osteosarcoma from 1987 to 2000 were reviewed. Patients were treated with the chemotherapy regimens recommended for nonmetastatic disease in children (the French Society of Pediatric Oncology OS 87 and OS 94 protocols) or, in a few patients, with other chemotherapy regimens. Surgical excision of the primary tumor and, when possible, of all metastatic sites was performed based on a personalized assessment of each patient's situation.

RESULTS: Seventy-eight patients age < 20 years were treated. Forty-six patients (59%) had only 1 metastatic site (35 to the lungs and 11 to bone). Twenty-eight patients (36%) achieved a complete remission after combination chemotherapy and surgery. The event-free survival and overall survival rates at 5 years were 14% and 19%, respectively. To date, 14 patients (18%) have remained alive with a median follow-up of 112 months. Pretreatment features associated with a shorter event-free survival in the multivariate analysis were metastasis to at least two organs and high alkaline phosphatase level. Patients with at least 1 of these poor prognostic factors had a 2.6% event-free survival rate at 5 years despite treatment.

CONCLUSIONS: The survival of patients with metastatic osteosarcoma were treated with conventional chemotherapy and surgery remained very poor. Patients should be classified into different prognostic groups and treated accordingly. New therapeutic approaches are warranted to improve the prognosis for patients with the most severe disease.