[Clinical analysis of mandibular osteoradionecrosis].

Radiotherapy thought vital in treating head and neck cancer, occasionally causes seriously local complications such as mandibular osteoradionecrosis (ORN). An analysis of mandibular ORN cases showed 16 in 638 subjects treated by radiotherapy, for an ORN rate of 2.5%. This rate was highest in subjects with oral cancer excluding the tongue, administered 81 Gy radiation dose, using X-ray plus electronic beams. 8 cases of ORN occurred within 1 year following radiation, and the 8 others within 5 years. Preservation treatment was successful in 44% of ORN cases, including surgery, for which the rate of final cure was 63%. With case of cancer recurrence, the rate was 25%. In 2 subjects dying of aspiration pneumonia, the cause should be a particular point for reflection. Radiotherapy involving mandibular bone should include special consideration related to the radiation source, radiation dose. Once ORN occurred, we should take care of the mixed cancer and dysphagia in the treatment.