Prospective Cohort Study of Carotid Intima-media Thickness after Irradiation

Risk, prevention, screening and management of carotid artery stenosis in head & neck cancer patients-An evidence based review

Our review aims to clarify the incidence of carotid artery stenosis, risks of development, screening, management, and primary prevention strategies documented in the literature after radiation therapy for head and neck cancers. The high prevalence of carotid stenosis after radiation therapy for head and neck cancers has made surveillance and risk stratification critical. In addition to general cardiovascular risk factors such as smoking, diabetes, and dyslipidemia, risk factors for carotid artery stenosis after head and neck radiation included total plaque score, radiotherapy use and dosage, length of time after radiotherapy, and age greater than 50. Cancer subtype, namely nasopharyngeal cancer, may be correlated with increased risk as well, though contrasting results have been found. Interestingly, however, no significant relationship has been found between radiotherapy dose and stroke risk. Surgical management of post-radiation carotid stenosis is similar to that of stenosis unrelated to radiation, with carotid endarterectomy considered to be the gold standard treatment and carotid artery stenting being an acceptable, less-invasive alternative. Medical management of these patients has not been well-studied, but antiplatelet therapy, statins, and blood pressure control may be beneficial. The mainstay of screening for radiation-induced stenosis has been Doppler ultrasound, with measurement of changes in the intima-media thickness being a primary marker of disease development. A literature review was carried out using the MeSH terms "Carotid Artery Stenosis," "Head and Neck Neoplasms," and "Radiotherapy."

Vascular events in patients with head and neck cancer: A systematic review and meta-analysis

OBJECTIVE

To assess the incidence of vascular events in patients with head and neck cancer.

REVIEW METHODS

Primary studies identified through April 2023. Meta-analysis was performed.

RESULTS

There were 146 studies included in the systematic review. Rates of events were collected in the overall group, those with chemoprophylaxis, and those that underwent surgery, radiation, or chemotherapy. Of 1 184 160 patients, 4.3% had a vascular event. Radiation therapy had highest risk of overall events and stroke when compared to surgery and chemotherapy. Chemotherapy had a higher risk of stroke and overall events when compared to surgery.

CONCLUSIONS

Vascular events occur in 4%-5% of patients with head and neck cancer. Our data does not support the use of routine anticoagulation. Patients undergoing radiation therapy had the highest frequency of events.

Traditional risk factors and cancer-related factors associated with cardiovascular disease risk in head and neck cancer patients

Background

Risk of incident cardiovascular disease (CVD) in head and neck squamous cell carcinoma (HNSCC) patients is under-reported. We assessed the association of HNSCC-related factors and traditional risk factors with 1- and 5-year CVD risk in HNSCC patients without prevalent CVD at cancer diagnosis.

Methods

A clinical cohort of 1,829 HNSCC patients diagnosed between 2012 and 2018, at a National Cancer Institute (NCI)-designated cancer center was included. Information on HNSCC-related factors [HNSCC anatomical subsite, stage at diagnosis, treatment, and tumor human papillomavirus (HPV) status] were extracted from the tumor registry. Data on traditional risk factors (hypertension, dyslipidemia, diabetes, tobacco smoking status, and obesity) were extracted from the electronic health records system (EHR) at baseline (HNSCC diagnosis). A composite of ischemic heart disease, heart failure, and ischemic stroke was the outcome of interest in time to event analysis. Hazard ratio (HR) (95% CI) were reported with death as a competing risk.

Results

In patients diagnosed with HNSCC, 10.61% developed incident CVD events by 1-year post cancer diagnosis. One-year CVD risk was lower in patients using antihypertensive medications at baseline, compared to patients without baseline hypertension [HR (95% CI): 0.41 (0.24-0.61)]. One-year CVD risk was high in patients receiving HNSCC surgery. Patients receiving radiation therapy had a higher 5-year CVD risk than surgery patients [HR (95% CI): 2.17 (1.31-3.04)]. Patients using antihypertensive medications had a lower 5-year CVD risk than patients without baseline hypertension [HR (95% CI): 0.45 (0.22-0.75)]. Older age and diabetes were associated with increased 1- and 5-year CVD risk. HPV-negative patients were older (p 0.006) and had a higher 5-year cumulative incidence of CVD (p 0.013) than HPV-positive patients.

Conclusion

Traditional risk factors and cancer-related factors are associated with CVD risk in HNSCC patients. Future research should investigate the role of antihypertensive medications in reducing CVD risk in HNSCC patients.

Magnetic resonance guided elective neck irradiation targeting individual lymph nodes: A new concept

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Individual elective lymph nodes can be identified using multiple Dixon T2-weighted turbo spin echo with fat suppression.

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Magnetic Resonance guided individual lymph node irradiation results in lower dose to the organs at risk.

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Especially the submandibular glands, carotid arteries and thyroid can be spared.

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The magnetic field on the magnetic resonance imaging - linear accelerator did not lead to increased skin dose depositions.

Background and purpose

Conventional elective neck irradiation (ENI) in head and neck cancer consists of radiotherapy (RT) to the regional lymph node (LN) levels contoured on computed tomography. Hybrid Magnetic Resonance (MR) - RT modalities, such as combined magnetic resonance imaging - linear accelerators (MRLs), might enable new ENI strategies in which individual non-suspect lymph nodes (i-LNs) are targeted. In this treatment planning study, new MR-based strategies targeting i-LNs (i-ENI) were compared to conventional treatment.

Materials and methods

All i-LNs were delineated on MR images of ten retrospectively selected patients with T2-4aN0M0 laryngeal cancer. Three strategies were considered. Strategy A: Conventional ENI delivered with a conventional linear accelerator (35x 1.55 Gy). Strategy B: MRL-based i-ENI (35x 1.55 Gy) to the individual lymph nodes including a background dose to the conventional elective neck volumes (35x 1.03 Gy). Strategy C: Same as Strategy B, but without background dose. In all plans the dose prescription to the primary tumor was 35x 2 Gy. Mean dose (D_mean) reductions in the organs at risk (OAR) were compared using the Wilcoxon signed rank test.

Results

Compared to conventional ENI (strategy A), significant D_mean reductions of 6.0 Gy and 8.0 Gy were observed in the submandibular glands, of 9.4 Gy and 13 Gy in the carotid arteries and of 9.9 Gy and 19.4 Gy in the thyroid for strategy B and C, respectively. Large inter-patient variations of D_mean reductions were observed in all OARs.

Conclusion

MRL-based i-ENI is a new promising concept that could reduce the mean dose to OARs in the neck significantly for patients with laryngeal cancer.

Screening for irradiation vasculopathy by intima-media thickness sonography in head and neck cancer patients

Purpose

Post-irradiation vasculopathy is a severe form of atherosclerosis and affects the prognosis of head and neck cancer survivors. Sonographic intima-media thickness (IMT) precedes stenosis, plaque formation, and cerebrovascular events. Therefore, IMT may be a valuable screening marker for post-irradiation toxicity. However, the critical irradiation dose and the onset of IMT increase remain unclear.

Methods

The cross-sectional study analysed the carotid artery IMT in 96 irradiated patients and 41 controls regarding irradiation dose, post-irradiation-interval, and cardiovascular risk factors. Distinct irradiation doses to the tumour side and the contralateral hemineck enabled detection of dose depended effects within one patient and control of risk factors.

Results

Radiotherapy caused a dose-dependent increase in IMT. The toxicity did not have saturation effects for > 60 Gy. The IMT increase occurred in short-term following radiotherapy and the risk for a pathological value (> 0.9 mm) rose significantly. The correlation between IMT and radiotherapy was comparable to established cardiovascular risk factors.

Conclusion

Radiotherapists should consider the additional toxicity of high doses for non-metastatic head and neck cancer. If neck metastases require radiotherapy with boost, IMT measurement is suitable for early detection of carotid artery damage.

Changes in the Common Carotid Artery after Radiotherapy: Wall Thickness, Calcification, and Atherosclerosis

BACKGROUND AND PURPOSE

Since the long-term survival rate has improved in laryngeal cancer patients who receive radiotherapy, concerns about postradiation complications (including carotid atherosclerosis) have increased. We followed changes in the common carotid artery (CCA) after radiotherapy and identified the underlying risk factors.

METHODS

Consecutive patients with laryngeal cancer who underwent radiotherapy between January 1999 and December 2009 and who had received computed tomography (CT) both pre- and postradiotherapy were enrolled. Changes in the wall thickness and in the vessel and lumen areas as well as the presence of calcification or atherosclerosis were investigated. Demographics and risk factors were compared between patients with and without atherosclerosis at follow-up CT.

RESULTS

In total, 125 patients were enrolled. The wall thickness had increased and the lumen area had decreased several months after radiotherapy. These changes were not associated with vascular risk factors and were not progressive. Calcification and atherosclerosis were observed in 37 (29.6%) and 71 (56.8%) patients, respectively. Diabetes was associated with calcification (p=0.02). The prevalence of hyperlipidemia was higher in patients with atherosclerosis (28.2% vs. 11.1%, p=0.02) and for a longer period postradiation [62.7±32.1 vs. 40.0±24.2 months (mean±SD), p<0.001]. Atherosclerosis occurred mostly in the middle portion of the CCA (n=31, 24.6%), followed by the proximal CCA at the intrathoracic level (n=26, 20.6%) and the distal CCA (n=6, 4.8%). Positive remodeling was also observed, but this was less common in patients with calcification (p=0.02).

CONCLUSIONS

Various types of postradiation changes occur in the CCA and can be easily observed in postradiation CT. The prevalence and burden of postradiation atherosclerosis increased in a close relationship with baseline cholesterol levels and the time after radiotherapy. Postradiation atherosclerosis was observed at unusual sites of the CCA.

Intensity-modulated radiotherapy for early glottic cancer: transition to a new standard of care?

For decades, the standard of care for radiation treatment of early larynx cancers has been conventional treatment using opposed lateral fields encompassing the larynx and overlying neck structures, including the adjacent carotid arteries. While intensity-modulated radiotherapy (IMRT) has replaced conventional radiotherapy for all other head/neck cancer situations, the use of IMRT to treat early glottic cancers remains controversial. The article reviews the published experience with IMRT for this clinical situation and provides a detailed review of the literature on radiation-induced carotid toxicity and how it might apply to the controversy. Finally, we discuss whether the radiation oncology community should transition to IMRT as a new standard of care for the treatment of early glottic cancers.