Detection of radiation-induced, accelerated atherosclerosis in patients with osteoradionecrosis by panoramic radiography

Purpose: Osteoradionecrosis (ORN) of the mandible has long been considered the most destructive complication of head and neck irradiation. Recently, therapeutic irradiation has been implicated as the cause of induced/accelerated atherosclerosis of the cervical carotid artery and subsequent stroke. Panoramic radiography, previously shown to be capable of identifying carotid artery atherosclerosis in nonirradiated individuals, was used to assess the carotid vasculature of patients being treated for ORN. Patients and Methods: The panoramic radiographs of 61 men (mean age, 60.5 years; range, 41 to 77 years) who received therapeutic irradiation to the neck 36 months or more previously were assessed for the presence of carotid artery atherosclerotic lesions. Sixty-one control subjects who never received therapeutic irradiation, but who were similarly susceptible to atherosclerosis by virtue of age, were assessed in a like manner. Results: The irradiated individuals sustained a dose of 40 to 72 Gy to the area of the carotid bifurcation. Seventeen individuals (27.9%) with an irradiation dosage to the carotid bifurcation that averaged 59.2 Gy had a panoramic radiograph with a carotid atheroma (11 with unilateral lesions and six with bilateral lesions). The radiographs of the control subjects showed that three individuals (4.9%) had calcified carotid lesions. The mean age of these subjects was 66.1 years; two had unilateral lesions, and one had bilateral lesions. The difference in the proportion of individuals with ORN who manifested carotid artery atherosclerosis on their panoramic radiographs was statistically significant (P = .001) when compared with the nonirradiated control subjects. The lesions seen in both populations had a similar morphologic appearance and were radiographically located within the soft tissues of the neck 1.5 to 4.0 cm inferior-posterior to the angle of the mandible. Conclusions: Individuals with radiation doses sufficient to cause osteoradionecrosis of the mandible are at significantly higher risk of developing carotid artery atherosclerotic lesions than age-matched, nonirradiated controls.