Assessment of the Advancement of Alveolar Bone Loss in Canine Patients Receiving Definitive Radiotherapy for Sinonasal Tumors

Radiotherapy for the treatment of sinonasal tumors in dogs is generally well tolerated, but the range of long-term adverse effects remains poorly understood. In people receiving radiation for head and neck tumors, existing dental disease is a predisposing factor for radiation-induced oral complications that can lead to worsening periodontal disease long-term. Periodontal disease is widespread amongst the population of senior dogs typically undergoing radiotherapy, and the aim of this retrospective cohort study was to determine if there is evidence of increased alveolar bone loss in these patients. Computed tomography scans from canine patients undergoing definitive intent radiotherapy for sinonasal tumors at a veterinary teaching hospital from 2013 to 2022 were utilized to assess alveolar bone loss in the maxillary and mandibular premolars and molars at multiple follow-up time points. As the radiation dose delivered was concentrated to the maxilla, the mandibular teeth served as a control for the expected degree of alveolar bone loss. Analysis indicated that there is an increase in alveolar bone loss over time, but that there is no difference between the mandible and maxilla. This finding provides evidence that the risk of radiotherapy worsening alveolar bone loss is low in canine patients and is the first study evaluating the relationship between alveolar bone loss and radiation-induced side effects in dogs. Continued long-term follow-up, along with similar investigations for tumors more directly affecting the oral cavity, is essential to appropriately guide patient risk assessment and prophylaxis.