Systematic review of the incidence and risk factors for cerebral vasculopathy and stroke after cranial proton and photon radiation for childhood brain tumors

Radiation therapy for childhood-onset craniopharyngioma: systematic review and meta-analysis

BACKGROUND

Craniopharyngioma (CP), a benign tumor originating from remnants of Rathke's pouch in the sellar region, accounts for approximately 30% of all cases of craniopharyngioma. Radiation therapy has been used to treat CP patients for decades; however, there is still a lack of systematic reviews on the long-term tumor control outcomes in pediatric CP patients treated with external radiation therapy.

METHODS

We conducted a comprehensive search of multiple databases for studies on the tumor progression rates of childhood-onset CP(COCP) patients who received external radiotherapy. We also recorded morbidities related to hypopituitarism and vasculopathy. A meta-analysis was performed to calculate the pooled incidence rates. Meta-regression was applied to explore potential sources of heterogeneity in the tumor progression rates.

RESULTS

A total of 22 studies were included after screening and eligibility assessment in accordance with PRISMA guidelines. The median (mean) follow-up period ranged from 2 to 14.9 years. The pooled overall tumor progression rate was 0.10 (95% CI 0.07-0.15). The recurrence rates were 0.14 (95% CI 0.09-0.19) for photon therapy and 0.04 (95% CI 0.01-0.07) for proton therapy. Meta-regression indicated that none of the following underlying risk factors significantly affected the heterogeneity of the recurrence rate: radiation modality (photon vs. proton), median (mean) follow-up duration, or the proportion of patients who did not undergo surgical resection. The pooled incidence of growth hormone deficiency (GHD), thyroid hormone deficiency (THD), adrenocorticotropic hormone deficiency (ACTHD), gonadotropin-releasing hormone deficiency (GnRHD), and diabetes insipidus (DI) were 0.81 (95% CI 0.70-0.90), 0.88 (95% CI 0.79-0.95), 0.69 (95% CI 0.52-0.85), 0.43 (95% CI 0.38-0.49), and 0.56 (95% CI 0.33-0.78), respectively. The pooled morbidity rate for vasculopathy was 0.06 (95% CI 0.04-0.09), with similar rates observed for both photon and proton therapy.

CONCLUSION

Radiotherapy is a suitable adjuvant or alternative treatment method for childhood CP patients. However, patients inevitably face significant long-term treatment-related complications.

Moyamoya syndrome after proton beam therapy in a pediatric patient with a pineal germ cell tumor and a germline polymorphism in RNF213

The effects of RNF213, which leads to moyamoya disease susceptibility, on radiation-induced moyamoya syndrome (MMS) remain unknown. We report a case of MMS after proton beam therapy (PBT) was deployed to treat a brain tumor in a patient with an RNF213 polymorphism. An 8-year-old boy underwent whole ventricular and local PBT for a pineal germ cell tumor and was diagnosed with radiation-induced MMS 9 months later. He underwent right and left revascularization surgeries for cerebral hemodynamic compromise at 17- and 18-years of age, respectively. Genetic analysis revealed a heterozygous germline polymorphism RNF213 p.R4810K. This is the first report to suggest an association between RNF213 polymorphism and radiation-induced MMS.

Feasibility of transcranial Doppler to evaluate vasculopathy among survivors of childhood brain tumors exposed to cranial radiation therapy

BACKGROUND

The ability of transcranial Doppler (TCD) to detect asymptomatic cerebrovascular disease among childhood brain tumor survivors following exposure to cranial radiation therapy has not been established.

METHODS

Survivors of childhood brain tumors, more than 3 years since diagnosis and exposed to greater than 30 Gy cranial radiation, underwent a history and physical exam, laboratory biomarkers of cerebrovascular disease (cholesterol, high-density lipoprotein cholesterol (HDL), low-density lipoprotein cholesterol (LDL), high-sensitivity CRP, hemoglobin A1C, apoprotein A, and apoprotein B), and a TCD evaluation of their cerebral arteries.

RESULTS

In all 165 cerebral arteries from 13 patients (medulloblastoma = 10; germ cell tumor = 3; females = 5; mean age at diagnosis = 8.0 years; mean age at time of study = 20.9 years) were examined. Twenty-eight of 165 (17%) were considered abnormal by pre-specified criteria. Total 114 cerebral arteries from 13 patients were assessed for greater than 50% stenosis velocities. Arteries most likely to be considered abnormal included the distal bilateral vertebral arteries (right 38%, left 30%), basilar artery 30%, bilateral siphon internal carotid arteries (right 30%, left 23%), bilateral middle cerebral arteries (23% bilaterally), and bilateral anterior cerebral arteries (7% bilaterally). Two vessels had mean flow velocities consistent with ≥ $ \ge $ 50% stenosis (1.8%). No vessels were found to have greater than 80% stenosis.

CONCLUSIONS

TCD may be a useful and practical tool to examine asymptomatic cerebrovascular disease among childhood brain tumor survivors after exposure to cranial radiation therapy. Posterior circulation vessels appear to have the highest burden of disease in this group of brain tumor survivors, a majority of whom had medulloblastoma.

Proton Radiation Therapy: A Systematic Review of Treatment-Related Side Effects and Toxicities

Cancer is the second leading cause of death worldwide. Around half of all cancer patients undergo some type of radiation therapy throughout the course of their treatment. Photon radiation remains (RT) the most widely utilized modality of radiotherapy despite recent advancements in proton radiation therapy (PBT). PBT makes use of the particle's biological property known as the Bragg peak to better spare healthy tissue from radiation damage, with data to support that this treatment modality is less toxic than photon RT. Hence, proton radiation dosimetry looks better compared to photon dosimetry; however, due to proton-specific uncertainties, unexpected acute, subacute, and long-term toxicities can be encountered. Reported neurotoxicity resulting from proton radiation treatments include radiation necrosis, moyamoya syndrome, neurosensory toxicities, brain edema, neuromuscular toxicities, and neurocognitive toxicities. Pulmonary toxicities include pneumonitis and fibrosis, pleural effusions, and bronchial toxicities. Pericarditis, pericardial effusions, and atrial fibrillations are among the cardiac toxicities related to proton therapy. Gastrointestinal and hematological toxicities are also found in the literature. Genitourinary toxicities include urinary and reproductive-related toxicities. Osteological, oral, endocrine, and skin toxicities have also been reported. The side effects will be comparable to the ones following photon RT, nonetheless at an expected lower incidence. The toxicities collected mainly from case reports and clinical trials are described based on the organs affected and functions altered.

Clinical significance of cerebral microbleeds in patients with germinoma who underwent long-term follow-up

PURPOSE

This study identified the factors affecting cerebral microbleed (CMBs) development. Moreover, their effects on intelligence and memory and association with stroke in patients with germinoma who had long-term follow-up were evaluated.

METHODS

This study included 64 patients with germinoma who were histologically and clinically diagnosed with and treated for germinoma. These patients were evaluated cross-sectionally, with a focus on CMBs on susceptibility-weighted magnetic resonance imaging (SWI), brain atrophy assessed through volumetric analysis, and intelligence and memory.

RESULTS

The follow-up period was from 32 to 412 (median: 175.5) months. In total, 43 (67%) patients had 509 CMBs and 21 did not have CMBs. Moderate correlations were observed between the number of CMBs and time from initial treatments and recurrence was found to be a risk factor for CMB development. Increased temporal CMBs had a marginal effect on the processing speed and visual memory, whereas brain atrophy had a statistically significant effect on verbal, visual, and general memory and a marginal effect on processing speed. Before SWI acquisition and during the follow-up periods, eight strokes occurred in four patients. All of these patients had ≥ 15 CMBs on SWI before stroke onset. Meanwhile, 33 patients with < 14 CMBs or 21 patients without CMBs did not experience stroke.

CONCLUSION

Patients with a longer time from treatment initiation had a higher number of CMBs, and recurrence was a significant risk factor for CMB development. Furthermore, brain atrophy had a stronger effect on memory than CMBs. Increased CMBs predict the stroke onset.

Stroke in Asia

BACKGROUND

There is a significant burden of stroke in Asia. Asia has the largest population in the world in 2023, estimated at 4.7 billion. Approximately 9.5-10.6 million strokes will be anticipated annually in the backdrop of a diverse group of well-developed and less developed countries with large disparities in stroke care resources. In addition, Asian countries are in varying phases of epidemiological transition.

SUMMARY

In this review, we examined recent epidemiological features of ischaemic stroke and intracerebral haemorrhage in Asia with recent developments in hyperacute stroke reperfusion therapy and technical improvements in intracerebral haemorrhage. The article also discussed the spectrum of cerebrovascular diseases in Asia, which include intracranial atherosclerosis, intracerebral haemorrhage, infective aetiologies of stroke, moyamoya disease, vascular dissection, radiation vasculopathy, and cerebral venous thrombosis.

KEY MESSAGES

The review of selected literature and recent updates calls for attention to the different requirements for resources within Asia and highlights the breadth of cerebrovascular diseases still requiring further research and more effective therapies.

Outcome after proton beam therapy versus photon-based radiation therapy in childhood-onset craniopharyngioma patients-results of KRANIOPHARYNGEOM 2007

Background

Proton beam therapy (PBT) is being increas16ingly used to treat residual craniopharyngioma (CP) after hypothalamus-sparing surgery. Compared to photon-based radiation therapy (XRT) with PBT, less irradiation in the penumbra reduces the scattered dose to critical organs neighboring but outside the area of treatment, minimizing the risk of sequelae.

Patients and methods

Between 2007 and 2019, 99 of 290 (34%) childhood-onset CP patients recruited in KRANIOPHARYNGEOM 2007 received external radiation therapy (RT) (65% PBT, 35% XRT). Outcome was analyzed in terms of survival, endocrinological and anthropometric parameters (BMI and height SDS), quality of life (QoL using PEDQOL), and functional capacity (FMH) with special regard to irradiation technique.

Results

PBT became predominant (used in 43% and 72% of all irradiated patients registered within the first and second halves of the recruitment period, between 2008 and 2013 and 2013 and 2018, respectively). Five-year event-free survival rates after PBT or XRT were comparable (92% ± 4% vs. 91% ± 4%, p = 0.42) and higher than for the whole cohort since diagnosis, including non-RT patients (37% ± 4%). Radiation doses to the hypothalamus and pituitary did not differ between PBT and XRT. Endocrine deficits due to disturbances of the hypothalamic-pituitary axis (HPA) were already common before irradiation. During the first 5 years after CP diagnosis/RT, no differences between PBT, XRT, and non-RT CP patients concerning functional capacity and anthropometric parameters have been obtained. Only for the PEDQOL domain "physical function", parental-assessed QoL was lower 12 months after PBT versus XRT or non-RT patients.

Conclusion

QoL, functional capacity, degree of obesity, and endocrinopathy varied over time from diagnosis, but by 5 years, there was no significant difference between PBT and XRT upfront or delayed, nor was there any compromise in historic survival rates, which remained high >90%. RT of any type is extremely effective at stabilizing disease after hypothalamic-sparing surgery. The purported specific benefits of PBT-reducing sequelae are not proven in this study where the organ of critical interest is itself diseased, increasing an urgent need to better address and treat the tumor-induced endocrine harm from diagnosis in dedicated pituitary services. Other hypothesized benefits of PBT versus XRT on vascular events and secondary cancers await longer comparison.

Clinical trial registration number

https://clinicaltrials.gov/study/, identifier NCT01272622.

The tumor micro-environment in pediatric glioma: friend or foe?

Brain tumors are the leading cause of morbidity and mortality related to cancer in children, where high-grade glioma harbor the worst prognosis. It has become obvious that pediatric glioma differs significantly from their adult counterparts, rendering extrapolations difficult. Curative options for several types of glioma are lacking, albeit ongoing research efforts and clinical trials. As already proven in the past, inter- and intratumoral heterogeneity plays an important role in the resistance to therapy and thus implicates morbidity and mortality for these patients. However, while less studied, the tumor micro-environment (TME) adds another level of heterogeneity. Knowledge gaps exist on how the TME interacts with the tumor cells and how the location of the various cell types in the TME influences tumor growth and the response to treatment. Some studies identified the presence of several (immune) cell types as prognostic factors, but often lack a deeper understanding of the underlying mechanisms, possibly leading to contradictory findings. Although the TME in pediatric glioma is regarded as "cold", several treatment options are emerging, with the TME being the primary target of treatment. Therefore, it is crucial to study the TME of pediatric glioma, so that the interactions between TME, tumoral cells and therapeutics can be better understood before, during and after treatment. In this review, we provide an overview of the available insights into the composition and role of the TME across different types of pediatric glioma. Moreover, where possible, we provide a framework on how a particular TME may influence responses to conventional- and/or immunotherapy.

Review of Cerebral Radiotherapy-Induced Vasculopathy in Pediatric and Adult Patients

Radiation therapy (RT) causes radiation-induced vasculopathy, which requires clinicians to identify and manage this side effect in pediatric and adult patients. This article reviews previous findings about the pathophysiology of RT-induced vascular injury, including endothelial cell injury, oxidative stress, inflammatory cytokines, angiogenic pathways, and remodeling. The vasculopathy is categorized into ischemic vasculopathy, hemorrhagic vasculopathy, carotid artery injury, and other malformations (cavernous malformations and aneurysms) in populations of pediatric and adult patients separately. The prevention and management of this RT-induced side effect are also discussed. The article summarizes the distribution and risk factors of different types of RT-induced vasculopathy. This will help clinicians identify high-risk patients with corresponding vasculopathy subtypes to deduce prevention and treatment strategies accordingly.

Adult Moyamoya Disease and Syndrome: Current Perspectives and Future Directions: A Scientific Statement From the American Heart Association/American Stroke Association

Adult moyamoya disease and syndrome are rare disorders with significant morbidity and mortality. A writing group of experts was selected to conduct a literature search, summarize the current knowledge on the topic, and provide a road map for future investigation. The document presents an update in the definitions of moyamoya disease and syndrome, modern methods for diagnosis, and updated information on pathophysiology, epidemiology, and both medical and surgical treatment. Despite recent advancements, there are still many unresolved questions about moyamoya disease and syndrome, including lack of unified diagnostic criteria, reliable biomarkers, better understanding of the underlying pathophysiology, and stronger evidence for treatment guidelines. To advance progress in this area, it is crucial to acknowledge the limitations and weaknesses of current studies and explore new approaches, which are outlined in this scientific statement for future research strategies.

The incidence of radiation-induced moyamoya among pediatric brain tumor patients who received photon radiation versus those who received proton beam therapy: a systematic review

Cranial irradiation is associated with several adverse events such as endocrinopathy, growth retardation, neurocognitive impairment, secondary malignancies, cerebral vasculopathy, and potential stroke. The better side effects profile of proton beam therapy compared with that of photon radiation therapy is due to its physical properties, mainly the sharp dose fall-off after energy deposition in the Bragg peak. Despite the better toxicity profile of proton beam therapy, the risk of  moyamoya syndrome still exists. We conducted a systematic review of the existing literature on moyamoya syndrome after receiving cranial radiation therapy for pediatric brain tumors to investigate the incidence of moyamoya syndrome after receiving photon versus proton radiation therapy. In this review, we report that the incidence of moyamoya syndrome after receiving proton beam therapy is almost double that of photon-induced moyamoya syndrome. Patients who received proton beam therapy for the management of pediatric brain tumors are more likely to develop moyamoya syndrome at the age of less than 5 years. Meanwhile, most patients with proton-induced moyamoya are more likely to be diagnosed within the first 2 years after the completion of their proton beam therapy.

Proton therapy for pediatric diencephalic tumors

Diencephalic tumors tend to be low grade tumors located near several critical structures, including the optic nerves, optic chiasm, pituitary, hypothalamus, Circle of Willis, and hippocampi. In children, damage to these structures can impact physical and cognitive development over time. Thus, the goal of radiotherapy is to maximize long term survival while minimizing late effects, including endocrine disruption leading to precocious puberty, height loss, hypogonadotropic hypogonadism, and primary amenorrhea; visual disruption including blindness; and vascular damage resulting in cerebral vasculopathy. Compared to photon therapy, proton therapy offers the potential to decrease unnecessary dose to these critical structures while maintaining adequate dose to the tumor. In this article, we review the acute and chronic toxicities associated with radiation for pediatric diencephalic tumors, focusing on the use of proton therapy to minimize treatment-related morbidity. Emerging strategies to further reduce radiation dose to critical structures will also be considered.

Head and Neck Cancer Types and Risks of Cervical-Cranial Vascular Complications within 5 Years after Radiation Therapy

Background and purpose: to investigate the frequency of cervical−cranial vascular complications soon after radiation therapy (RT) and identify differences among patients with various types of head and neck cancer (HNC). Methods: We enrolled 496 patients with HNC who had received their final RT dose in our hospital. These patients underwent carotid duplex ultrasound (CDU) for monitoring significant carotid artery stenosis (CAS). Brain imaging were reviewed to detect vertebral, intracranial artery stenosis, or preexisted CAS before RT. Primary outcome was significant CAS at the internal or common carotid artery within first 5 years after RT. We categorized the patients into nasopharyngeal carcinoma (NPC) and non-NPC groups and compared the cumulative occurrence of significant CAS between the groups using Kaplan−Meier and Cox-regression analyses. Results: Compared to the NPC group, the non-NPC group had a higher frequency of significant CAS (12.7% vs. 2.0%) and were more commonly associated with significant CAS after adjusting the covariates (Adjusted hazard ratio: 0.17, 95% confident interval: 0.05−0.57) during the follow-up period. All the non-NPC subtypes (oral cancer/oropharyngeal, hypopharyngeal, and laryngeal cancers) were associated with higher risks of significant CAS than the NPC group (p < 0.001 respectively). Conclusion: Significant CAS was more frequently noted within 5 years of RT among the patients with non-NPC HNC than among the patients with NPC. Scheduled carotid artery surveillance and vascular risk monitoring should be commenced earlier for patients with non-NPC HNC. By contrast, vascular surveillance could be deferred to 5 years after RT completion in NPC patients.

Short and Long-Term Toxicity in Pediatric Cancer Treatment: Central Nervous System Damage

Simple Summary

The purpose of this review is to describe central nervous system side effects in the treatment of pediatric cancer patients. Unfortunately, we must consider that the scarce data in the literature does not allow us to expand on some issues, especially those related to innovative immunotherapy. We have described the major neurotoxicities arising with the various types of treatment to help specialists who approach these treatments recognize them early, prevent them, and treat them promptly.

Abstract

Neurotoxicity caused by traditional chemotherapy and radiotherapy is well known and widely described. New therapies, such as biologic therapy and immunotherapy, are associated with better outcomes in pediatric patients but are also associated with central and peripheral nervous system side effects. Nevertheless, central nervous system (CNS) toxicity is a significant source of morbidity in the treatment of cancer patients. Some CNS complications appear during treatment while others present months or even years later. Radiation, traditional cytotoxic chemotherapy, and novel biologic and targeted therapies have all been recognized to cause CNS side effects; additionally, the risks of neurotoxicity can increase with combination therapy. Symptoms and complications can be varied such as edema, seizures, fatigue, psychiatric disorders, and venous thromboembolism, all of which can seriously influence the quality of life. Neurologic complications were seen in 33% of children with non-CNS solid malign tumors. The effects on the CNS are disabling and often permanent with limited treatments, thus it is important that clinicians recognize the effects of cancer therapy on the CNS. Knowledge of these conditions can help the practitioner be more vigilant for signs and symptoms of potential neurological complications during the management of pediatric cancers. As early detection and more effective anticancer therapies extend the survival of cancer patients, treatment-related CNS toxicity becomes increasingly vital. This review highlights major neurotoxicities due to pediatric cancer treatments and new therapeutic strategies; CNS primary tumors, the most frequent solid tumors in childhood, are excluded because of their intrinsic neurological morbidity.

Delineation atlas of the Circle of Willis and the large intracranial arteries for evaluation of doses to neurovascular structures in pediatric brain tumor patients treated with radiation therapy

BACKGROUND

Survivors of pediatric brain tumors are susceptible to neurovascular disease after radiotherapy, with dose to the chiasm or Circle of Willis (CW) as risk factors. The aims of this study were to develop a delineation atlas of neurovascular structures, to investigate the doses to these structures in relation to tumor location and to investigate potential dose surrogates for the CW dose.

MATERIAL AND METHODS

An atlas of the CW, the large intracranial arteries and the suprasellar cistern (SC) was developed and validated. Thirty proton plans from previously treated pediatric brain tumor patients were retrieved and grouped according to tumor site: 10 central, 10 lateralized, and 10 posterior fossa tumors. Based on the atlas, neurovascular structures were delineated and dose metrics (mean dose (D_mean) and maximal dose (D_max)) to these structures and the already delineated chiasm were evaluated. The agreement between dose metrics to the CW vs. chiasm/SC was investigated. The minimal Hausdorff distance (HD_min) between the target and SC was correlated with the SC D_mean.

RESULTS

The median D_mean/D_max to the CW were 53 Gy(RBE)/55 Gy(RBE) in the central tumors, 18 Gy(RBE)/25 Gy(RBE) in the lateralized tumors and 30 Gy(RBE)/49 Gy(RBE) in the posterior fossa tumors. There was a good agreement between the D_max/D_mean to the CW and the SC for all cases (R²=0.99), while in the posterior fossa group, the CW D_max was underestimated when using the chiasm as surrogate (R²=0.76). Across all patients, cases with HD_min < 10 mm between the target and the SC received the highest SC D_mean.

CONCLUSION

The pattern of dose to neurovascular structures varied with the tumor location. For all locations, SC doses could be used as a surrogate for CW doses. A minimal distance larger than 10 mm between the target and the SC indicated a potential for neurovascular dose sparing.