Osteoradionecrosis After Modern Radiotherapy for Oral Cavity Cancer: Incidence and Risk Factors

Objectives: Osteoradionecrosis (ORN) incidence after head and neck cancer (HNC) directed radiation therapy has recently been reported to be 1%-40%. The objective of this study is to establish contemporary incidence of ORN for patients treated with IMRT exclusively for oral cavity squamous cell carcinoma (OCSCC). Methods: This study is a retrospective chart review of 172 patients treated for OCSCC at a single institution from 2013 to 2022. All patients received adjuvant radiation with or without chemotherapy. Patient charts were reviewed to identify ORN. ORN was defined as exposure of bone with radiographic findings and/or physical exam findings. Data collected including age, gender, smoking status, AJCC 8th edition stage, mandibulectomy or maxillectomy as part of surgery, hospitalization in between surgery and RT, and concurrent chemotherapy. Results: Mean follow up for the entire cohort was 46.1 months. The incidence of ORN in our cohort of patients was 24% at 3 years. 51.5% of patients underwent mandibulectomy or maxillectomy prior to radiation. 28.4% of patients with mandibulectomy or maxillectomy developed ORN. 18.1% of the patients treated without mandibulectomy or maxillectomy went on to develop ORN. Hazard ratio for development of ORN when patients underwent mandibulectomy or maxillectomy was 1.93. Conclusion: ORN development is higher in oral cavity SCC when compared to published ORN rates in mixed HNC cohorts. Mandibulectomy and/or maxillectomy as part of surgical treatment for OCSCC increases risk for ORN development. Level of Evidence: Level 3.