Pediatric Craniofacial Osteosarcoma: The Milano Experience

Abstract

Background: Craniofacial osteosarcoma (CFOS) is a rare tumor, typically affecting patients over 60, with a low incidence of metastasis at diagnosis as well as at relapse.

Patients and methods: This study analyzed patients treated for high-grade CFOS at Fondazione IRCCS Istituto Nazionale dei Tumori between 1991 and 2021, focusing on histological characteristics, systemic and local treatment, and outcome.

Results: Eleven patients (7F/4M) were included, with a median age of 15 years. Eight patients had an unfavorable site of origin (maxilla, cranial fossae, skull), seven had an unfavorable histology (i.e., chondroblastic subtype), and four had a high-grade tumor (G4). Five had both unfavorable histology and primary tumor site, and three of the five a G4 tumor. Chemotherapy (MAP or MAPI regimen) was administered to all, with five receiving neoadjuvant treatment. Surgery was performed on all, achieving clear margins in eight patients (four of them had received neoadjuvant CT). Two of three patients with R1 surgery received adjuvant radiotherapy (RT) and are still alive and disease-free. Three patients died of relapse, all with unfavorable primary tumor sites, G4 tumors, and two with unfavorable histology; one patient with positive margins had not received RT. At a median follow-up of 65.8 months, 5-year PFS was 100% for favorable tumor sites, 50% for unfavorable sites, and 85% for G3 tumors compared to 25% for G4 tumors.

Conclusion: Unfavorable tumor sites and G4 tumors may be indicative of a worse prognosis, especially as all relapsed patients had both. RT should be considered for R1 surgery. Due to the disease's rarity and complexity, specialized centers with expertise in head and neck sarcoma are essential for managing these patients.

Keywords: chemotherapy; grading; histologic subtype; osteosarcoma; primary tumor site; radiotherapy; sequelae; surgery.