Abstract Background Proton-beam-therapy (PBT) is being increasingly used, supplementing surgical treatment of central nervous system (CNS) tumours in paediatric patients. PBT enables targeted radiation delivery in skull base, spinal and brain tumours including medulloblastoma. However, concerns exist about related radiation-induced vasculopathy and stroke, which are potential complications. Delayed vascular injury including large vessel stenosis, occlusion, and aneurysm formation can occur thereby necessitating long-term imaging surveillance. In addition, stroke-like migraine attacks after radiation therapy (SMART syndrome) has been reported after PBT, where endothelial dysfunction and hyperexcitability causes clinical presentation of stroke-like neurological deficit with imaging findings of gyral thickening and enhancement. Methods We report two paediatric cases with complications such as radiation-induced vasculopathy and SMART syndrome following PBT. Results 1.A 13-year-old child with craniopharyngioma underwent surgical resection. Tumour recurrence within one year necessitated further surgery followed by proton beam therapy. After seven years, follow-up imaging revealed a progressive stenosis of the left internal carotid artery, although clinically asymptomatic. Repeat magnetic resonance angiography, after a transient ischemic attack, identified severe occlusion of the left ICA, A1 segment and a watershed infarct consistent with Moya Moya disease. An encephaloduroarteriosynangiosisprocedure was subsequently performed. 2.A 6-year-old child with medulloblastoma had debulking surgery and chemotherapy for residual tumour and subsequently underwent PBT craniospinal irradiation achieving remission. The following year, the patient developed epilepsy and experienced a neurovascular event characterized by SMART-like episodes, with MRA revealing narrowing of the right middle cerebral artery which resolved on follow up imaging. Conclusion Childhood cancer survivors receiving PBT remain at risk for radiation-induced vasculopathy, which may have varied or very delayed presentations. Increasing familiarity with clinical and radiological presentations, including rare syndromes such as SMART and Moya Moya and surveillance vascular imaging play an essential role in early detection and treatment and may require support with perfusion techniques.
Aygün et al. (Tue,) studied this question.