Carotid endarterectomy for postradiation carotid stenosis in patient with hypopharyngeal cancer: a case report

Abstract

Background

Radiation therapy for head and neck tumors is associated with radiation-induced carotid injury, which increases the risk of carotid artery stenosis and cerebrovascular events. Despite the well-established risks, routine screening for these complications has not been incorporated into clinical practice. This case emphasizes that, despite severe fibrosis and adhesion in the neck tissues resulting from radiation therapy, a well-structured surgical evaluation can still lead to favorable outcomes. It highlights the importance of timely surgical intervention in such cases.

Case presentation

A 60-year-old male of Asian descent presented with a 1-month history of episodic dizziness, persistent headache, and right lower limb weakness. Imaging studies demonstrated severe stenosis (70–99%) at the origin of the left internal carotid artery, accompanied by reduced cerebral perfusion in the left hemisphere and inadequate collateral circulation. The patient had a prior history of hypopharyngeal cancer treated with surgery, chemotherapy, and radiotherapy 4 years earlier, which subsequently led to radiation-induced carotid artery stenosis. He underwent left carotid endarterectomy, which revealed substantial fibrosis and dense adhesions, complicating the dissection. An eversion technique was employed to achieve complete plaque removal, and postoperative angiography confirmed restored vascular patency. Histopathological analysis showed marked intimal thickening, collagen deposition, and calcification. The patient’s recovery was uneventful, with full resolution of symptoms by postoperative day 4 and follow-up imaging demonstrating significantly improved cerebral perfusion.

Conclusion

Carotid endarterectomy can safely and effectively improve cerebral perfusion and alleviate symptoms in patients with carotid artery stenosis following radiation therapy, provided there is thorough preoperative evaluation and meticulous surgical exposure. In addition, it is essential to strengthen carotid artery assessment and long-term follow-up for survivors of head and neck radiation therapy.

Background

Patients with head and neck tumors often undergo RT as a primary treatment. While RT is effective in cancer treatment, it also induces several radiation-related side effects, particularly damage to the carotid artery [1]. Radiation-induced carotid injury (RICI) is a common complication of RT. It can lead to carotid artery stenosis (CAS) and significantly increase the risk of cerebrovascular events (CVE) and stroke [2, 3]. Existing literature indicates that RT-induced CAS typically develops several years after RT. Its severity may worsen over time [4]. In recent years, although the damage caused by RT to neck tissues is increasingly recognized, routine screening and treatment protocols for carotid artery stenosis are still lacking in clinical guidelines. Some studies suggest that carotid endarterectomy (CEA) is an effective treatment for symptomatic severe CAS in patients with RT-induced carotid artery stenosis. However, owing to the destruction of neck structures by RT, especially the fibrosis and adhesion formation, CEA procedures are associated with higher risks [5]. This case reports a patient with severe carotid artery stenosis caused by postoperative RT for hypopharyngeal cancer. It explores the application and outcomes of CEA in such cases, providing a reference for the diagnosis and treatment of similar patients.

Case report

A 60-year-old male patient of Asian descent was admitted with a 1-month history of episodic dizziness, persistent headache, and right lower limb weakness. Clinical examination revealed weakened muscle strength in the right lower limb, suggesting potential neurological impairment. Upon admission, a carotid computed tomography angiography (CTA) was performed, which revealed severe stenosis at the origin of the left internal carotid artery, with the degree of stenosis estimated to be approximately 70–99% (Fig. 1a–c). In addition, arterial spin labeling (ASL) imaging showed significantly reduced perfusion in the left frontal, temporal, parietal, and occipital lobes, with insufficient collateral circulation (Fig. 1d). At 4 years earlier, the patient was diagnosed with hypopharyngeal cancer and subsequently underwent partial laryngectomy, resection of the hypopharyngeal malignancy, and pharyngeal reconstruction. At 3 months after surgery, the patient began chemotherapy with a TP regimen, consisting of liposomal paclitaxel 300 mg on day 1 and nedaplatin 150 mg on day 1, administered every 30 days for a total of three cycles. Approximately 10 days after completing the final chemotherapy cycle, the patient initiated radiotherapy with a total dose of 6600 cGy delivered in 30 fractions, administered five times per week over three cycles. Approximately 3 years and 3 months after treatment, the patient began to experience symptoms of dizziness and headache; however, no carotid artery assessments had been performed. Based on the available imaging results and the patient’s medical history, a preliminary diagnosis of radiation-induced carotid artery stenosis was made. To treat the patient’s carotid artery stenosis, a left CEA was planned. During the procedure, exposure of the carotid artery revealed that the subcutaneous fat, muscle tissue, and other normal structures were severely damaged by radiation, resulting in significant fibrosis and dense adhesions. After clamping the superior thyroid artery, external carotid artery, internal carotid artery, and common carotid artery in sequence, the internal carotid artery (ICA) was transected transversely at its origin. Circumferential dissection was performed along the intimal-medial plane of the ICA, allowing the arterial wall to be everted in a sleeve-like fashion to expose and separate the atherosclerotic plaque. The dissection continued proximally until a transition zone with healthy intima was reached, at which point the plaque was sharply excised. Subsequently, plaques in the common and external carotid arteries were removed. Finally, the transected end of the ICA was reanastomosed to its original position using an end-to-side technique. A eversion technique was used to successfully remove the plaques from both the internal and common carotid arteries (Fig. 2a, b). After plaque excision, vascular reconstruction was performed, and intraoperative angiography showed widening of the internal carotid artery lumen with restored blood flow (Fig. 2c, d). The postoperative pathological report indicated significant thickening of the carotid intima with collagen deposition, focal necrosis, foam cell accumulation, and calcification (Fig. 3a, b). Postoperatively, the patient recovered well, with complete resolution of headache, dizziness, and right lower limb weakness by the fourth day after surgery. The cranial nerve function was not impaired. Follow-up CTA demonstrated a marked widening of the previously stenosed carotid artery segment (Fig. 4a–c). ASL imaging also showed significant improvement in perfusion in the left frontal, temporal, parietal, and occipital lobes compared with preoperative scans (Fig. 4d). The patient was discharged and continued on atorvastatin 20 mg daily and aspirin 100 mg daily for lipid-lowering and antiplatelet therapy. Subsequent follow-up indicated no recurrence of symptoms.

Fig. 1.

Carotid computed tomography angiography reveals severe stenosis at the origin of the left internal carotid artery, with an estimated stenosis degree of 70–99% (A–C). The position marked by the red arrow is the location of carotid artery stenosis. Arterial spin labeling shows reduced perfusion in the left frontal, temporal, parietal, and occipital lobes, along with insufficient collateral circulation (D)

Fig. 2.

Plaque distribution in the internal carotid artery is relatively extensive (A, B). Intraoperative angiography reveals that the plaque is primarily located at the origin of the left internal carotid artery (C). Post-plaque removal and vascular anastomosis, follow-up angiography shows an enlarged internal carotid artery diameter with restored blood flow (D)

Fig. 3.

Histopathological findings: the specimen revealed intimal thickening with atherosclerotic plaque formation. Microscopically, the vessel wall showed prominent thickening with collagenization, focal necrosis with foam cell aggregation, and calcium salt deposition. (A) Hematoxylin–eosin stain, × 100; (B) Hematoxylin–eosin stain, × 200

Fig. 4.

Postoperative carotid computed tomography angiography demonstrates a significant increase in the diameter of the previously stenotic segment of the left internal carotid artery (A–C). The position marked by the red arrow is the surgical location. Arterial spin labeling shows marked improvement in perfusion in the left frontal, temporal, parietal, and occipital lobes compared with preoperative findings (D)

Discussion

RT is one of the primary treatment modalities for head and neck cancer (HNC). Ongoing research into the mechanisms of RT-induced damage has led to increasing attention towards RICI. A recent meta-analysis of 35,000 HNC survivors showed that, when accounting for risk factors such as diabetes, coronary artery disease, peripheral artery disease, and smoking, neck radiation significantly increases the risk of CAS and CVE. The risk was found to increase by a factor of 3.98 [6]. The time interval for the first detection of CAS after RT varies in the literature. Some studies suggest that CAS can be detected within 1–2 years, while others report it may take 10–15 years [7], Furthermore, the severity of CAS typically worsens over time [3, 8]. Owing to the limited follow-up period after RT, late-stage vascular events may not be captured in a timely manner, complicating the establishment of a clear dose–response relationship. Currently, carotid artery screening is not routinely performed in patients with HNC who have undergone neck RT. Most radiotherapy oncology centers treating patients with HNC have not incorporated routine CAS screening into their clinical protocols, likely owing to a lack of sufficient clinical evidence and guidance [9].

The surgical treatment of CAS following RT primarily includes CEA and carotid artery stenting. According to the guidelines from the Society for Vascular Surgery, CEA should be considered the first-line treatment for symptomatic severe CAS [10]. Existing studies suggest that, compared with carotid artery stenting, CEA is associated with a lower incidence of perioperative complications, including cerebrovascular accidents, myocardial infarction, and death. In addition, CEA offers similar mid- and long-term outcomes in the treatment of RT-induced CAS [11]. However, the long-term restenosis rate after carotid artery stenting is significantly higher than that after CEA. On the other hand, despite the favorable outcomes of CEA, it may carry a higher risk of nerve injury. Overall, both CEA and carotid artery stenting are safe and effective treatment options, with the choice of procedure depending on the patient’s specific condition and risk assessment [12–14]. The guidelines do not distinguish RICS as a separate treatment category. The 2023 Clinical Practice Guidelines of the European Society for Vascular Surgery address RICS as a distinct clinical entity. While acknowledging the lack of randomized controlled trials specific to RICI, the guidelines suggest that treatment decisions should be individualized on the basis of lesion characteristics, such as length, plaque morphology, and neck anatomy altered by prior radiation [10]. In patients with high surgical risk due to severe fibrosis or scarring from previous radiation therapy, carotid artery stenting may be considered a reasonable alternative to CEA. These recommendations are classified as weak, supported by low-level evidence, reflecting the need for further research in this area.

Color Doppler ultrasound and carotid CTA are commonly used in the preoperative evaluation of CAS. Both techniques have advantages and limitations in assessing plaque characteristics, the degree and extent of stenosis, and collateral circulation. For a comprehensive evaluation, multidimensional imaging techniques should be employed to obtain the following key parameters: Doppler ultrasound identifies plaque location, extent, maximum thickness, stenosis rate, and peak systolic flow velocity [15]. CTA, on the other hand, further assesses the degree of stenosis, extent, bifurcation location, and the presence of plaque calcification [16]. Thorough preoperative assessment and a detailed surgical plan are essential prerequisites for the successful execution of CEA. RT-induced damage to the neck tissues compromises normal structures such as subcutaneous fat and muscle, leading to severe fibrosis and increased difficulty in surgical exposure. This also increases the risk of nerve injury. The calcification and dense adhesion of plaques further complicate the process of intimal dissection, significantly increasing the likelihood of vascular rupture. Therefore, meticulous and careful dissection and plaque removal during surgery are critical to preventing nerve and vascular injury. Postoperatively, patients must continue lipid-lowering therapy and antiplatelet treatment to reduce the risk of restenosis [13, 17].

In the early stages of CAS, most patients receive lipid-lowering and antiplatelet therapy, which effectively slows the progression of RICI-induced CAS. For patients with severe stenosis, the use of lipid-lowering and antiplatelet medications before CEA significantly reduces the risk of perioperative stroke and mortality. Antiplatelet agents such as aspirin and clopidogrel are effective in reducing the risk of stroke, but studies suggest that their combined use does not further enhance the protective effect. The mechanisms underlying RICI remain incompletely understood but primarily involve vascular inflammatory damage, intimal hyperplasia, and adventitial fibrosis [2, 18]. In addition, RT may also lead to the transformation of stable plaques into vulnerable plaques. Radiation-induced plaque pathology resembles that of atherosclerotic plaques. However, the former is more likely to be associated with intimal or medial fibrosis, plaque calcification, foam cell accumulation, and reduced lipid core size. Liposomal paclitaxel and nedaplatin are generally considered to have minimal direct vascular toxicity. While isolated case reports have suggested that paclitaxel may trigger myocardial infarction in patients with severe coronary artery stenosis [19], and nedaplatin has been associated with increased cholesterol levels [20], no large-scale clinical trials have confirmed a causal relationship between these agents and accelerated atherosclerosis. Therefore, we believe that their contribution to carotid artery disease in this case is likely negligible. Traditional atherosclerotic CAS typically occurs at the carotid bifurcation and the origin of the internal carotid artery, while radiation-induced CAS often affects the common carotid artery and presents as more diffuse, widespread, and severe stenosis [21, 22]. Recent studies have indicated that bone marrow mononuclear cells (BMMNCs) may have a potential therapeutic advantage in RICI, as they can reduce carotid artery inflammation, oxidative stress, and delay the progression of atherosclerosis. BMMNCs possess strong proliferative abilities and can secrete a variety of cytokines to modulate immune responses, promote wound healing, inhibit radiation-induced vascular activation, and limit the interaction between leukocytes and endothelial cells [23]. Although the application of BMMNCs in the treatment of RICI holds significant promise, further clinical research is required to validate their use.

Conclusion

Currently, CEA is an effective treatment for CAS following RT. A comprehensive preoperative evaluation is essential, and an individualized surgical plan should be developed for each patient. Owing to RT-induced damage to neck tissues, including the destruction of normal structures and severe fibrosis, the difficulty of surgical exposure is increased. Therefore, meticulous and careful dissection and exposure are key to minimizing the risk of vascular and neurological injury. Rigorous postoperative follow-up is essential to ensure the effectiveness of the treatment. At present, carotid artery screening is not routinely performed following RT for HNC, and further research is needed to refine the risk prediction models for patients with HNC and identify those who would most benefit from targeted screening and early preventive strategies. As our understanding of the mechanisms underlying RICI deepens, more effective treatment options may emerge. Early screening and intervention for RICI will likely become critical strategies to improve patient prognosis and quality of life.

Abbreviations

ASL

Arterial spin labeling

BMMNC

Bone marrow mononuclear cells

CAS

Carotid artery stenosis

CVE

Cerebrovascular events

CEA

Carotid endarterectomy

CTA

Computed tomography angiography

HNC

Head and neck cancer

ICA

Internal carotid artery

RT

Radiation therapy

RICI

Radiation-induced carotid injury

Author contributions

SFL and JWM contributed to the conception and design of the study. MYQ interpreted the data and drafted the manuscript. LC and LY collected clinical data and conducted patient follow-up. All the authors critically revised the manuscript for important intellectual content.

Funding

This study was supported by the National Natural Science Foundation of China (Grant No. 82471427).

Data availability

Data are provided within the manuscript.

Declarations

Ethics approval and consent to participate

The research involving human participants was approved by the Ethics Committee of Qingdao University Affiliated Hospital. These studies were conducted in accordance with local legislation and institutional requirements. Participants provided written informed consent to participate in this study.

Consent for publication

Written informed consent was obtained from the patient for the publication of this case report and any related images. A copy of the written consent is available for review by the editor-in-chief of this journal.

Competing interests

The authors declare that the research was conducted without any commercial or financial relationships that could be construed as potential competing interests.