Does intensity-modulated radiation therapy lower the risk of osteoradionecrosis of the jaw? A long-term comparative analysis.

The aim of this study was to analyze the impact of different radiation techniques on the long-term incidence of osteoradionecrosis in head and neck cancer. Risk factors and the occurrence of osteoradionecrosis were analyzed in a retrospective, comparative, observational study. Medical files and radiological images of 109 patients treated with primary intensity-modulated radiation therapy (IMRT) and 129 patients treated with primary three-dimensional conformal radiotherapy (3D-CRT) were evaluated. Proportional hazards models were used to analyse the effects of the radiation modality and patient characteristics on the necrosis risk. Twenty-two patients developed osteoradionecrosis (9.2%) during a mean follow-up of 4.3 years. A numerical difference was observed, with more osteoradionecrosis after 3D-CRT (n=18) than after IMRT (n=4). After correction for group differences and confounders, no statistical difference in risk was observed between the two treatment groups (P=0.37). Multivariate analysis showed evidence of a higher osteoradionecrosis risk for patients with a tumour of the oropharynx and for patients with tooth extraction after radiation therapy. Although the incidence of osteoradionecrosis tended to be lower after IMRT, due to the multifactorial aetiology it remains a severe problem and cannot be prevented by new radiotherapy techniques. Continuous efforts are necessary to control additional risk factors and avoid osteoradionecrosis.