The role of panoramic radiography in determining an increased risk of cervical atheromas in patients treated with therapeutic irradiation.

PURPOSE Therapeutic irradiation of the neck is a common component of treatment for those with carcinoma of the oral cavity, pharynx, and larynx. Such irradiation, however, has been implicated as the cause of accelerated atherosclerosis of the cervical carotid artery and subsequent stroke. Panoramic radiography, previously shown to be capable of identifying carotid artery atherosclerosis in non-irradiated individuals, was used to assess the carotid vasculature of patients who had been treated for cancer with therapeutic irradiation. METHODS The panoramic radiographs of 33 male subjects who had received therapeutic irradiation (> or = 50 Gy) to the neck 30 or more months previously were assessed for the presence of calcified carotid artery atherosclerotic lesions. Age-matched controls, similarly liable for oropharyngeal malignancy and atherosclerosis by virtue of their medical and habitual risk factors (hypertension, smoking, obesity) were assessed in a like manner. RESULTS The panoramic radiographs of the irradiation-treated subjects (age range, 32 to 84 years; mean age, 66.1 years) showed that 21% (7 of 33 subjects) had calcified atherosclerotic lesions. The mean age of these seven subjects was 64.6 years; four had unilateral lesions and three had bilateral lesions. The radiographs of the control subjects showed that 4.7% (5 of 107 subjects) had calcified atherosclerotic lesions. The mean age of these five subjects was 67; three had unilateral lesions and two had bilateral lesions. The lesions seen in the two populations had similar morphologic appearances. The discrete radiopaque calcifications were located within the soft tissues of the neck, approximately 2.5 cm inferior-posterior to the angle of the mandible. CONCLUSIONS Subjects who had received therapeutic irradiation of the neck had a statistically higher risk (p = 0.007, according to Fisher's Exact Test) of the development of calcified carotid artery atherosclerotic lesions than age-matched, risk-matched, non-irradiated control subjects. These lesions can be detected on routine panoramic radiographs.