Lack of efficacy of neoadjuvant chemotherapy in adult patients with maxillo-facial high-grade osteosarcomas: A French experience in two reference centers

INTRODUCTION: Neoadjuvant chemotherapy (neo-CT) for osteosarcomas is the standard of care. Management of maxillo-facial osteosarcomas (MFOS) is challenging. In this rare disease, we collected a large cohort of patients with the aim to report the histological and radiological local response rates to neo-CT. PATIENTS AND METHODS: All consecutive adult patients treated between 2001 and 2016 in two French sarcoma referral centers (Pitié-Salpêtrière Hospital, APHP, RESAP France and Gustave Roussy Institute France), for a histologically proved MFOS were included. Clinical, histological and radiological data were independently reviewed. Tumor response to neo-CT was assessed clinically, radiologically with independent review using RECIST v1.1 criterion and pathologically (percentage of necrosis). Multivariate analysis was done for outcomes, tumor response and disease-free survival (DFS). RESULTS: A total of 35 high grade MFOS were collected. The clinical tumor response was 4% (1/24 receiving neo-CT), the radiological response was 0% (0/18 with available data) and the pathological response was 5% (1/20 with available data). Three patients (12.5%) initially resectable became unresectable due to clinical and radiological progression during neo-CT. Tumor size and R0 (clear margins) surgical resections were significantly associated with DFS. CONCLUSION: MFOS is a rare disease. This large retrospective cohort of MFOS indicates the lack of benefit and potentially deleterious effects of neo-CT. We suggest privileging primary surgery in initially localized resectable MFOS. The benefit of adjuvant chemotherapy should be prospectively studied.