Pediatrics Surface Osteosarcomas: A French Multicenter Study (SURFOS), Which is the Most Appropriate Treatment?

Background: Most of osteosarcomas (OS) originate on the medullary canal, and only a small proportion arises from the surface of bone. Surface OS can be divided into three distinct histologic subtypes: parosteal OS, periosteal OS and high-grade surface OS. This national retrospective study was conducted to review the treatment and clinical outcome of children surface’ OS in order to upgrade and homogenize practices. Methods: Data of 28 pediatric patients with surface OS treated in 11 French Cancer Centers (SFCE) between 1990 and 2010 were reviewed. Results: Eleven patients had parosteal, sixteen patients had periosteal and one patient had high-grade surface OS. The median age at the diagnosis was 14.3 years (range, 5.8 –17.9 years). Seven patients were male. None had metastatic disease at diagnosis. All 28 patients were treated with surgery, of whom 21 (7 parosteal, 13 periosteal and 1 high-grade tumors) received chemotherapy (adjuvant or neo-adjuvant). Three patients relapsed (local relapse for 1 patient with parosteal OS and distant relapses for two patients with periosteal OS) and four patients with periosteal OS developed a second cancer (three out of four died). The 11-year overall survival rate was 100% for parosteal OS and 63 ± 18% for periosteal OS. Conclusion: The histologic grade determines the clinical behavior and prognosis in pediatric surface OS. Complete resection is the treatment of choice regardless of pathology. Regarding prognosis, our study argues for the use of adjuvant chemotherapy in periosteal OS, as well as for oncogenetic counseling.