Do traditional risk stratification models for cerebrovascular events apply in irradiated head and neck cancer patients?

BACKGROUND: Primary radical radiotherapy (RT) for head and neck cancer (HNC) often results in significant radiation dose to the carotid arteries. AIM: We assessed whether HNC patients are at increased risk of a cerebrovascular event primarily due to RT or other risk factors for atherosclerosis by (i) risk-stratifying patients according to validated QRISK-2 and QSTROKE scores and (ii) comparing the prevalence of carotid artery stenosis (CAS) in irradiated and unirradiated carotid arteries. DESIGN: HNC patients treated with an RT dose >50 Gy to one side of the neck ≥2 years previously were included. METHODS: QRISK-2 (2014) and Q-STROKE (2014) scores were calculated. We compared the prevalence of CAS in segments of the common carotid artery on the irradiated and unirradiated sides of the neck. RESULTS: Fifty patients (median age of 58 years (interquartile range (IQR) 50-62)) were included. The median QRISK-2 score was 10% (IQR 4.4-15%) and the median QSTROKE score was 3.4% (IQR 1.4-5.3%). For both scores, no patient was classified as high risk. Thirty-eight patients (76%) had CAS in one or both arteries. There was a significant difference in the number of irradiated arteries with stenosis (N = 37) compared with unirradiated arteries (N = 16) (P < 0.0001). There were more plaques on the irradiated artery compared with the unirradiated side - 64/87 (73.6%) versus 23/87 (26.4%), respectively (P < 0.001). CONCLUSIONS: Traditional vascular risk factors do not play a role in radiation-induced carotid atherosclerosis. Clinicians should be aware that traditional risk prediction models may under-estimate stroke risk in these patients.

Clinical features of radiation-induced carotid atherosclerosis.

Carotid arteries frequently receive significant incidental doses of radiation during the treatment of malignant diseases, including head and neck cancer, breast cancer and lymphoma. Vascular injury after treatment may result in carotid artery stenosis and increased risk of neurological sequelae, such as stroke and transient ischaemic attack. The long latent interval from treatment to the development of clinical complications makes investigation of this process difficult, particularly in regard to the design of interventional clinical studies. Nevertheless, there is compelling clinical evidence that radiation contributes to carotid atherosclerosis. This overview examines the effect of radiotherapy on the carotid arteries, the underlying pathological processes and their clinical manifestations. The use of serum biomarkers in risk-prediction models and the potential value of new imaging techniques as tools for defining earlier surrogate end points will also be discussed.

The increased prevalence of left ventricular hypertrophy and concentric remodeling in U.K. Indian Asians compared with European whites.

Individuals of Indian Asian ethnicity living in the U.K. have at least a 50% excess of cardiovascular disease (CVD) mortality compared with European whites, yet there are no validated tools capable of identifying this excess risk. Left ventricular hypertrophy (LVH) is a powerful prognosticator for future CVD events but its prevalence in Indian Asians is unknown. We examined the prevalence of LVH and the degree of concentric remodeling amongst healthy U.K. Indian Asians compared with European whites recruited to the LOLIPOP (London Life Sciences Prospective Population) study. Transthoracic echocardiography was performed in 2127 subjects aged 35-75 years without history of clinical CVD events. The prevalence of LVH was defined and relative wall thickness was calculated to provide a measure of concentric remodeling. The prevalence of LVH was significantly higher amongst Indian Asian men as compared with European white men, with an unadjusted odds ratio (OR) of 1.8 (95% CI: 1.4-2.6). Following adjustment for clinical and hemodynamic variables, the magnitude of this effect increased (OR 2.8, 95% CI: 1.9-4.2). The degree of concentric remodeling was higher amongst Indian Asians as compared with European whites (adjusted relative wall thickness for men: 0.41 vs. 0.39, P<0.001; women: 0.40 vs. 0.38, P<0.01). An almost threefold higher prevalence of LVH amongst Indian Asian men and a greater degree of concentric remodeling amongst Indian Asian men and women was evident. Investigation of the mechanisms underlying the pathogenesis of LV remodeling and blood pressure etiology may help redress the excess CVD mortality observed in Indian Asians.