Predictors of the Extent of Carotid Atherosclerosis in Patients Treated with Radiotherapy for Nasopharyngeal Carcinoma

Abstract

ObjectiveTo determine the predictors of the extent of carotid atherosclerosis in patients treated with radiotherapy (RT) for nasopharyngeal carcinoma (NPC).MethodsThe present study investigated 129 post-RT NPC patients. Carotid atherosclerotic parameters, such as carotid intima-media thickness, carotid arterial stiffness and carotid plaque burden (plaque score, the presence of plaque and ≥50% stenosis) were assessed using ultrasonography. The association between carotid atherosclerotic parameters and nine potential predictors, including age, gender, post-RT duration, radiation dose, chemotherapy, diabetes mellitus, hypertension, hypercholesterolemia, and smoking, were determined using multiple regression. The cutoff values of age, post-RT duration and number of cardiovascular risk factors for the presence of carotid plaque or ≥50% carotid stenosis were analyzed using receiver operating characteristic (ROC) curve analysis. Multiple testing was corrected using Benjamini-Hochberg false discovery rate.ResultsAge, post-RT duration and number of cardiovascular risk factors were significantly associated with carotid plaque burden (corrected P value, Pcor<0.05). Age of 44.5 years (sensitivity = 99.2% and specificity = 50%, Pcor<0.01) and post-RT duration of 8.5 years (sensitivity = 75.7% and specificity = 64.3%, Pcor<0.001) were the cutoff values for detecting carotid plaque, while post-RT duration of 13.5 years (sensitivity = 66.7% and specificity = 71.6%, Pcor<0.001) and 1.5 cardiovascular risk factors (sensitivity = 40.7% and specificity = 84.3%, Pcor<0.05) were the cutoff values for screening ≥50% carotid stenosis.ConclusionsAge, post-RT duration and number of cardiovascular risk factors are significant predictors of carotid atherosclerosis in post-RT NPC patients. Post-RT NPC patients, who are at least 45 years old, with post-RT duration of 9 years or above, and/or have ≥2 cardiovascular risk factors, are more susceptible to carotid atherosclerosis.

Comparison of Significant Carotid Stenosis for Nasopharyngeal Carcinoma between Intensity-Modulated Radiotherapy and Conventional Two-Dimensional Radiotherapy

“…The difference may be attributed to different measurement methods as was discussed by the authors. Another study identified carotid stenosis (≥50%) in 20.9% of 129 NPC patients who underwent 2D-RT, similar with our result for all patients 20 . However, their published incidence rate was lower than ours for the 2D-RT group and higher for the IMRT group.…”

Longitudinal atherosclerotic changes after radio(chemo)therapy of hypopharyngeal carcinoma

“…Progressive carotid stenosis was observed over several years after radiotherapy [5,10,17], with the same observation being made for the general plaque burden [18,19]. With regards to IMT, long-term progression was seen in some but not all studies [19][20][21][22]. Most of these results, however, are based on cross-sectional studies.…”

“…The deleterious effect of radio(chemo)therapy on the carotid arteries is well known [11,[14][15][16]. Progressive carotid stenosis was observed over several years after radiotherapy [5,10,17], with the same observation being made for the general plaque burden [18,19]. With regards to IMT, long-term progression was seen in some but not all studies [19][20][21][22].…”

Bilateral thalamic and mesencephalic infarctions with hypopituitarism as long-term complications postradiotherapy

“…[ 17 ] Intima-media thickness of the common carotid artery is a marker of early changes in atherosclerosis, which could be measured by modern high-resolution ultrasound machines and has proved to be a powerful predictor of future cerebrovascular disease. [ 5 ] Early changes in postradiation carotid injury are asymptomatic; hence, it is recommended to regularly monitor the intima-media thickness of the common carotid artery after irradiation and perform timely interventions to avoid the occurrence of radiogenic vascular events.…”

“…[ 3 , 4 ] Exposure to radiation can result in accelerated atherosclerosis; both large extracranial arteries and intracranial arteries are reportedly damaged after radiotherapy, which may further lead to stenosis of the cranial arteries and increased risk of cerebral infarction or transient ischemic attack. [ 5 ] Therefore, radiation-induced cerebral infarction often develops after radiation treatment. [ 6 ] On the contrary, the hypothalamic-pituitary axis is an extraordinarily radiosensitive range of the central nervous system, and hypopituitarism is usually induced by radiotherapy.…”