Irradiation. A significant risk factor for carotid atherosclerosis.

Radiation exacerbates the development of atherosclerosis in the large arteries of animals and is postulated to do likewise in human beings. To study this relationship, we used high-resolution B-mode ultrasonography to measure carotid artery wall thickness in 29 previously irradiated head and neck cancer patients and compared the results with those of nine epidemiologically similar but nonirradiated head and neck cancer patients. Maximal intima-media thickness was greater in the study group (mean, 1.28 +/- SE 0.06 mm) than in the control group (mean, 0.90 +/- SE 0.05 mm). Even after the effects of age, hypertension, and tobacco consumption were controlled, these differences remained statistically significant. This study suggests that irradiation may contribute to the development of more severe and extensive carotid atherosclerosis in head and neck cancer patients who receive radiation therapy.