Magnetic resonance imaging of the carotid artery in long-term head and neck cancer survivors treated with radiotherapy

Carotid Artery Stenosis and Ischemic Stroke in Patients With Head and Neck Cancer Treated With Radiation Therapy: A Critical Review

The purpose of this review is to summarize the literature on carotid artery stenosis (CAS) and ischemic stroke (IS) in patients with head and neck cancer (HNC) treated with radiation therapy (RT) to guide assessment, screening, and management strategies. Patients treated with RT for HNC are at an elevated risk of developing CAS, with published meta-analyses demonstrating that CAS >50% occurs in approximately 25% of patients. Previous research suggests a 10-year cumulative incidence of stroke between 5.7% and 12.5%. Cardiovascular disease (CVD) risk prediction tools such as Qstroke, QRISK-2, and Framingham risk score perform poorly for predicting IS for patients with HNC who received RT. Duplex ultrasound is the most common imaging modality to assess CAS, but controversy remains as to the utility of screening asymptomatic individuals. Only 3 of the 5 major HNC survivorship guidelines acknowledge RT as a risk factor for CAS or IS, while only 1 makes a specific recommendation on screening for CAS (American Head and Neck Society). Within the general population, only 1 CVD guideline discusses RT as a risk factor for CAS (Society for Vascular Surgery). Clinicians involved in the care of patients with HNC treated with RT should be aware of the increased risk of CAS and IS and the challenges in risk prediction. Although there is a lack of evidence to make firm recommendations, HNC survivorship recommendations should ensure HNC survivors and primary care providers are informed of these risks and the importance of assessment and management of CVD risk factors. Future studies are required to refine risk prediction models in patients with HNC and to determine those most likely to benefit from targeted screening and initiation of early preventative strategies.

Stroke Risk in Survivors of Head and Neck Cancer

Importance

Survivors of head and neck cancers (HNC) have increased risk of stroke. A comprehensive report using standardized methods is warranted to characterize the risk and to inform on survivorship strategy.

Objective

To determine the stroke risk in subpopulations of survivors of HNC in Singapore.

Design, Setting, and Participants

This national, registry-based, cross-sectional study aimed to estimate stroke risk in subgroups of the HNC population between January 2005 and December 2020. Participants were identified from the Singapore Cancer Registry, the Singapore Stroke Registry, and the Registry of Birth and Deaths using relevant International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) and International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, Australian Modification (ICD-10-AM) codes. HNC subgroups were defined based on patient demographic, disease, and treatment factors. Data were analyzed from September 2022 to September 2023.

Exposure

Diagnosis of HNC.

Main Outcomes and Measures

Both ischemic and hemorrhagic stroke were studied. The age-standardized incidence rate ratio (SIRR) and age-standardized incidence rate difference (SIRD) were reported. The Singapore general population (approximately 4 million) served as the reference group for these estimations.

Results

A total of 9803 survivors of HNC (median [IQR] age at diagnosis, 58 [49-68] years; 7166 [73.1%] male) were identified. The most common HNC subsites were nasopharynx (4680 individuals [47.7%]), larynx (1228 individuals [12.5%]), and tongue (1059 individuals [10.8%]). A total of 337 individuals (3.4%) developed stroke over a median (IQR) follow-up of 42.5 (15.0-94.5) months. The overall SIRR was 2.46 (95% CI, 2.21-2.74), and the overall SIRD was 4.11 (95% CI, 3.37-4.85) strokes per 1000 person-years (PY). The cumulative incidence of stroke was 3% at 5 years and 7% at 10 years after HNC diagnosis. The SIRR was highest among individuals diagnosed at younger than 40 years (SIRR, 30.55 [95% CI, 16.24-52.35]). All population subsets defined by age, sex, race and ethnicity, HNC subsites (except tongue), stage, histology, and treatment modalities had increased risk of stroke compared with the general population. The SIRR and SIRD were significantly higher among individuals who had a primary radiation treatment approach (SIRR, 3.01 [95% CI, 2.64-3.43]; SIRD, 5.12 [95% CI, 4.18-6.29] strokes per 1000 PY) compared with a primary surgery approach (SIRR, 1.64 [95% CI, 1.31-2.05]; SIRD, 1.84 [95% CI, 0.923.67] strokes per 1000 PY).

Conclusions and Relevance

In this cross-sectional study of survivors of HNC, elevated stroke risks were observed across different age, subsites, and treatment modalities, underscoring the importance of early screening and intervention.

Assessing radiation-induced carotid vasculopathy using ultrasound after unilateral irradiation: a cross-sectional study

Background

Increased head and neck cancer (HNC) survival requires attention to long-term treatment sequelae. Irradiated HNC survivors have a higher ischemic stroke risk. However, the pathophysiology of radiation-induced vasculopathy is unclear. Arterial stiffness could be a biomarker. This study examined alterations in intima-media thickness (IMT) and stiffness-related parameters, shear wave (SWV) and pulse wave velocity (PWV), in irradiated compared to control carotids in unilateral irradiated patients.

Methods

Twenty-six patients, median 40.5 years, 5–15 years after unilateral irradiation for head and neck neoplasms underwent a bilateral carotid ultrasound using an Aixplorer system with SL18-5 and SL10-2 probes. IMT, SWV, and PWV were assessed in the proximal, mid, and distal common (CCA) and internal carotid artery (ICA). Plaques were characterized with magnetic resonance imaging. Measurements were compared between irradiated and control sides, and radiation dose effects were explored.

Results

CCA-IMT was higher in irradiated than control carotids (0.54 [0.50–0.61] vs. 0.50 [0.44–0.54] mm, p = 0.001). For stiffness, only anterior mid-CCA and posterior ICA SWV were significantly higher in the irradiated side. A radiation dose–effect was only (weakly) apparent for PWV (R²: end-systolic = 0.067, begin-systolic = 0.155). Ultrasound measurements had good–excellent intra- and interobserver reproducibility. Plaques had similar characteristics but were more diffuse in the irradiated side.

Conclusions

Increased CCA-IMT and SWV in some segments were seen in irradiated carotids. These alterations, even in young patients, mark the need for surveillance of radiation-induced vasculopathy.

Trial registration: clinicaltrials.gov (https://clinicaltrials.gov/ct2/show/NCT04257968).

Radiation-Induced Vascular Disease-A State-of-the-Art Review

Since the 1990s, there has been a steady increase in the number of cancer survivors to an estimated 17 million in 2019 in the US alone. Radiation therapy today is applied to a variety of malignancies and over 50% of cancer patients. The effects of ionizing radiation on cardiac structure and function, so-called radiation-induced heart disease (RIHD), have been extensively studied. We review the available published data on the mechanisms and manifestations of RIHD, with a focus on vascular disease, as well as proposed strategies for its prevention, screening, diagnosis, and management.

Prevalence of carotid plaque stenosis after head and neck radiotherapy – an observational study of 156 survivors

Summary: Background: Radiotherapy for head and neck cancer (HNC) represents a well-known predisposing factor for asymptomatic carotid artery lesions and acute cerebrovascular accidents. Our aim is to provide contemporary estimates on the prevalence, severity, and characteristics of carotid artery lesions in HNC survivors. Patients and methods: We prospectively included HNC patients who underwent radiotherapy and were free from the disease at the time of duplex ultrasound evaluation. Patients were re-contacted telephonically and those who agreed to participate were invited for an ambulatory visit when the investigators collected clinical information and performed duplex ultrasound examination based on a predefined protocol. Results: A total of 156 patients were included and underwent duplex ultrasound examination after a mean of 65.2 months from the last session of radiotherapy. A total of 36 patients (23.1%) had normal carotid arteries; mild, non-stenotic lesions were observed in 49.4% (n = 77) of patients; severe stenotic plaques were found in 27.5% (n = 43) of patients. One patient found with an asymptomatic occlusion of the left ICA. The prevalence of major cardiovascular risk factors and high radiation dose increased proportionally with plaque severity. Low echogenicity plaque was found in 59 (37.8%) patients on the right side and 57 (36.5%) on the left side; long segment plaque in 49 (31.4%) patients on the right side and in 47 (30.1%) on the left side; an atypical location of the lesions in 42 (26.9%) patients on the right side and in 48 (30.8%) on the left side. Conclusions: The prevalence of occlusion and severe stenosis after radiotherapy for HNC was very low in our study population. Low echogenicity plaque, long segment plaque, and an atypical location were common findings. Classic cardiovascular risk factors appear to have had a causative role: a routine screening of radiotherapy-treated patients might be necessary only in patients with concomitant cardiovascular risk factors or exposed to high-dose neck radiation.

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

Background

Radiotherapy treatment of head and neck cancer affects local arteries and increases the risk of stroke. This study aimed at a closer characterization of this damage and its development in time with a longitudinal study set up.

Methods

Male patients treated between 2011 and 2016 for hypopharyngeal carcinoma were identified from the in-house clinical data base. They were included into the study if besides the planning CT at least one additional CT image was available from follow-up (13 patients) or at least two MRI scans (16 patients of which 2 were already included). All patients received radiotherapy, and chemotherapy was administered to 16 patients. The time from the beginning of radiotherapy to the last available image ranged from 2 months to 4.5 years.

For six segments of the carotid arteries, the number and volume of atherosclerotic plaques were determined from the CT scans, and the intima media thickness from the MRI scans. Information on comorbid cardiovascular disease, hypertension and diabetes mellitus was retrieved from medical records.

Results

Total plaque volume rose from 0.25 cm³ before to 0.33 cm³ after therapy but this was not significant (p = 0.26). The mean number of plaques increased from 5.7 to 8.1 (p = 0.002), and the intima media thickened from 1.17 mm to 1.35 mm (p = 0.002). However, the mean intima media thickness practically did not change in patients with comorbid diabetes mellitus (p-value for homogeneity: 0.03). For patients without diabetes mellitus, dynamics of both plaque number and intima media thickness, was consistent with an increase until about one year after therapy and no further progression thereafter.

Conclusion

Our study confirmed the thickening of artery walls and the increase in the number of plaques. Results imply that definitive radiation damage to the artery walls can be determined not earlier than about one year after radiotherapy and there is no substantial deterioration thereafter. Reasons for the absence of an observable intima media thickening in patients with diabetes are unclear.

Common carotid artery dissection caused by radiotherapy: A case report

In the present study, a case of acute cerebral infarction with radiation-induced carotid artery dissection is reported. Carotid artery dissection is generally asymptomatic at the early stages. Due to the non-specific clinical manifestations of carotid artery dissection, a detailed inquiry of the past history of a patient has a critical role in making a diagnosis of radiation-induced common carotid artery dissection. Onset of acute ischemic stroke is the predominant manifestation, and for patients with a history of head-and-neck radiotherapy, dissection should be considered. The condition may progress rapidly, and result in a poor prognosis. Therefore, a correct early diagnosis and initiation of appropriate therapy may lead to rapid recovery, and influence the overall prognosis.