University of Cincinnati - Barrett Cancer Center Bellevue, KY, KY
A. A. Farley1, T. L. Petery1, N. Dick2, and V. Takiar3; 1University of Cincinnati College of Medicine, Cincinnati, OH, 2Independent, Cincinnati, OH, 3Department of Radiation Oncology, University of Cincinnati College of Medicine, Cincinnati, OH
Purpose/Objective(s): Rates of osteoradionecrosis (ORN) incidence after head and neck cancer (HNC) directed radiation therapy have recently been reported to be 5-10%, however these studies either report ORN rates in heterogenous HNC populations, or in oropharyngeal and oral cavity squamous cell carcinoma patients together. Thus, the objective of this study is to establish contemporary incidence for patients treated with IMRT exclusively for Oral Cavity Squamous Cell Carcinoma (OCSCC) as these patients often have disease adjacent to bone. Patient characteristics associated with development of ORN are also evaluated.Materials/
Methods: 172 patients treated for OCSCC at a single institution from 2013-2022 were retrospectively reviewed. All patients received adjuvant radiation with/without chemotherapy. Patients were excluded if they received < 50 Gy, had prior radiation therapy (RT), multiple primary malignancies, progression during treatment, 3D conformal RT or proton RT. All patients charts were reviewed to identify ORN. ORN was defined as exposure of bone with radiographic findings and/or physical exam findings. The initial day of radiation was defined as day 0. Dosimetric data for the mandible (Dmean/Dmax/D40) was collected (110 patients). Cox proportional hazard model was used to assess age, gender, smoking status, 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 (range 0.7-136.1). The pathologic staging of the cohort was 4.6% T1, 22% T2, 22% T3, and 49.4% T4a. 56% of patients received concurrent chemoradiation. 23.4% of patients developed ORN at some point during the follow-up period. The median time to develop ORN was 15.9 months (range 4.2-115.6); mean time to develop ORN was 25.1 months. Of the 172 treated patients, 51.5% of patients underwent mandibulectomy or maxillectomy prior to radiation. Notably, 28.4% of patients with mandibulectomy or maxillectomy developed ORN, while only 18.1% of the patients treated without mandibulectomy or maxillectomy went on to develop ORN. The hazard ratio for development of ORN when patients underwent mandibulectomy or maxillectomy was 1.93 (p=0.059). There was an insignificant hazard ratio associated with active smokers developing ORN of 1.39 (p= 0.422). The mean Dmax, D40, and Dmean of the mandible were 6266, 5255, and 4251 cGy, respectively. Conclusion: The incidence rate of ORN in our cohort of OCSCC patients is higher than historically reported incidence rates. These data highlight the significance of evaluating patients treated for OCSCC independently from those treated for oropharyngeal cancer with surgery. Our data also identify patients who are more likely to develop ORN and may therefore benefit from enhanced prevention and surveillance strategies.
