Spontaneous osteoradionecrosis—features and characteristics: the Memorial Sloan Kettering Cancer Center experience

Objectives Osteoradionecrosis (ORN) is a complication of head and neck radiation therapy (RT) and is associated with significant morbidity. The incidence of ORN is variable, and it has been speculated to be lower with advanced RT techniques. Risk factors that have been associated with the development of ORN mainly include trauma and a radiation dose to the head and neck region greater than 60 Gy. However, in a study conducted by our group, ORN developed spontaneously (without any known history of trauma or dentoalveolar procedure) in 82% of the ORN cohort following intensity-modulated radiation therapy (IMRT).The purpose of this study was to characterize spontaneous ORN and to compare spontaneous ORN with nonspontaneous ORN (e.g., related to trauma or dentoalveolar procedures). Study Design Following approval by the Institutional Review Board of the Memorial Sloan Kettering Cancer Center (MSKCC), the treatment records of 44 patients with spontaneous ORN (group A) and 24 patients with nonspontaneous ORN (group B) treated with IMRT at the MSKCC for head and neck cancer (HNCa) were identified and retrospectively reviewed. Average prescribed mean and maximum radiation doses for the region of ORN were calculated by using MSKCC's proprietary radiation treatment planning software. Furthermore, Fischer's exact test was used to compare patient characteristics, such as primary site, tumor stage, smoking status, and other comorbidities, between the spontaneous ORN group and the nonspontaneous ORN group. Results According to preliminary data from 12 patients in group A and 6 patients from group B, the patients in group A appeared to have been exposed to higher radiation doses (Dmax; greater than 70 Gy) compared with group B. Furthermore, no statistical significance was noted between the 2 groups with regard to primary tumor, tumor stage, smoking status, and comorbidities, such as cardiovascular disease and hypertension (P > .05). However, statistical significance was evident for diabetes in group B (P Conclusions Collection of data on the expanded cohort of patients from each group, as well as other variables, such as radiation therapy fractionation, is ongoing. Our initial data indicates that increased radiation dose greater than 70 Gy may be associated with the development of spontaneous ORN.