Objective

To determine the prevalence and correlation of various risk factors [radiation dose, periodontal status, alcohol and smoking] to the development of osteoradionecrosis (ORN).

Patients and methods

The records of 1023 patients treated with IMRT for oral cavity cancer (OCC) and oropharyngeal cancer (OPC) between 2004 and 2013 were retrospectively reviewed to identify patients who developed ORN. Fisher exact tests were used to analyze patient characteristics between ORN patients with OCC and OPC. Paired Wilcoxon tests were used to compare the dose volumes to the ORN and contralateral non-ORN sites. To evaluate an association between ORN and risk factors, a case-control comparison was performed. One to 2 ORN-free patients were selected to match each ORN patient by gender, tumor site and size. General estimation equations models were used to compare the risk factors in ORN cases and matched controls.

Results

44 (4.3%) patients developed ORN during a median follow-up time of 52.5months. In 82% of patients, ORN occurred spontaneously. Patients with OPC are prone to develop ORN earlier compared to patients with OCC (P=0.03). OPC patients received a higher Dmax compared to OCC patients (P=0.01). In the matched case-control analysis the significant risk factors on univariate analysis were poor periodontal status, history of alcohol use and radiation dose (P=0.03, 0.002 and 0.009, respectively) and on multivariate analysis were alcohol use and radiation dose (P=0.004 and 0.026, respectively).

Conclusion

In our study, higher radiation dose, poor periodontal status and alcohol use are significantly related to the risk of developing ORN.