Radiotherapy Increases Carotid Intima-Media Thickness in Patients with Nasopharyngeal Carcinoma Compared to a Healthy Control Group: A 6-Year Follow-Up Study

Background/Objective: Vascular abnormalities are the primary histological changes in individuals undergoing radiotherapy for nasopharyngeal carcinoma (NPC). We sought to validate the hypothesis that the duration post-radiotherapy is linked to the progression of carotid intima-media thickness (IMT) and further explored its connection with mortality. Methods: Twenty-nine NPC patients who underwent radiotherapy and seventeen healthy controls were examined by carotid ultrasound for measurement of IMT and carotid plaque score at the common carotid artery (CCA), carotid bifurcation, and internal carotid artery, with follow-ups more than 6 years. Results: Initially, there was no discernible difference in internal carotid IMT between NPC patients and normal controls. However, a noteworthy increase in carotid IMT was observed after 6 years of radiotherapy (p < 0.0001). The carotid plaque score in NPC patients significantly exceeded that of the control group after 6 years (p < 0.0001). Linear regression demonstrated a positive correlation between carotid IMT and the duration post-radiotherapy. Logistic regression suggested that age and carotid IMT were predictors of mortality in NPC patients. Conclusions: Our study substantiates the positive correlation between carotid IMT and the duration of follow-up after radiotherapy. It found an increase in carotid IMT and plaque formation six years after radiotherapy compared to the control group. An increased carotid IMT may be correlated to an increased mortality rate and needs to be explored in future studies. Consequently, we recommend regular follow-up carotid ultrasonography for NPC patients undergoing radiation therapy.