The central nervous system in childhood leukemia. III. Mineralizing microangiopathy and dystrophic calcification

Drug-Induced Seizures: Considerations for Underlying Molecular Mechanisms

A broad spectrum of chemical entities have been associated with drug-induced seizure (DIS), emphasizing the importance of this potential liability across various drug classes (e.g., antidepressants, antipsychotics, antibiotics, and analgesics among others). Despite its importance within drug safety testing, an understanding of the molecular mechanisms associated with DIS is often lacking. The etiology of DIS is understood to be a result of either a deficit in inhibitory (e.g., gamma aminobutyric acid) or an elevated excitatory (e.g., glutamate) signaling, leading to synchronous neuronal depolarization affecting various brain regions and impairing normal neurological functions. How this altered neuronal signaling occurs and how these changes interact with other non-brain receptor driven DIS-associated changes such as metabolic disturbances, electrolyte imbalances, altered drug metabolism, and withdrawal effects are poorly understood. Herein, we discuss important molecular mechanisms identified in DIS for several drugs and/or drug classes. With a better understanding of the molecular mechanisms associated with DIS, in vivo or in vitro models may be applied to characterize and mitigate DIS risk during drug development. Susceptibility stratification for DIS presents species differences in the following order beagle dogs > rodents and cynomolgus monkeys > Göttingen minipigs with a more than 2-fold difference between canines and minipigs, which is important to consider during non-clinical species selection. While clinical signs such as myoclonus, severe muscle jerks, or convulsions are often associated with abnormal epileptiform EEG activity, tremors are most of the time physiological and rarely observed with concurrent epileptiform EEG activity which need to be considered during DIS risk evaluation.

Management and Surveillance of Short- and Long-Term Sequelae of Radiation Therapy for the Treatment of Pediatric Brain Tumors

Radiation therapy (RT) is a mainstay for the treatment of pediatric brain tumors. As improvements in and sophistication of this modality continue to increase the survival of patients, the long-term sequelae of RT pose significant challenges in the clinical management of this patient population as they transition into adulthood. In this special edition, we review the short- and long-term effects of RT for the treatment of pediatric brain tumors and the necessary surveillance required for follow-up.

Recognizing Radiation-induced Changes in the Central Nervous System: Where to Look and What to Look For

Radiation therapy (RT) continues to play a central role as an effective therapeutic modality for a variety of tumors and vascular malformations in the central nervous system. Although the planning and delivery techniques of RT have evolved substantially during the past few decades, the structures surrounding the target lesion are inevitably exposed to radiation. A wide variety of radiation-induced changes may be observed at posttreatment imaging, which may be confusing when interpreting images. Histopathologically, radiation can have deleterious effects on the vascular endothelial cells as well as on neuroglial cells and their precursors. In addition, radiation induces oxidative stress and inflammation, leading to a cycle of further cellular toxic effects and tissue damage. On the basis of the time of expression, radiation-induced injury can be divided into three phases: acute, early delayed, and late delayed. Acute and early delayed injuries are usually transient and reversible, whereas late delayed injuries are generally irreversible. The authors provide a comprehensive review of the timeline and expected imaging appearances after RT, including the characteristic imaging features after RT with concomitant chemotherapy. Specific topics discussed are imaging features that help distinguish expected posttreatment changes from recurrent disease, followed by a discussion on the role of advanced imaging techniques. Knowledge of the RT plan, the amount of normal structures included, the location of the target lesion, and the amount of time elapsed since RT is highly important at follow-up imaging, and the reporting radiologist should be able to recognize the characteristic imaging features after RT and differentiate these findings from tumor recurrence. ^©RSNA, 2020.

Acute Pontine Ischemic Stroke in a Healthy Child With Intracranial Vasculopathy

Here we report the case of a previously healthy 8-year-old boy who presented with altered mental status, right facial droop and right-sided hemiplegia the day after playing in an inflatable bouncer. No head trauma was reported by the patient nor witnessed by the parents. Urgent magnetic resonance imaging (MRI) demonstrated acute ischemic infarction in the left pons; computed tomographic angiography excluded arterial dissection but identified a small hyperdense filling defect in the basilar artery, later confirmed to be a calcification at the origin of a perforating artery. Pediatric National Institutes of Health (PedNIH) Stroke Scale score was 15. Infectious, inflammatory, hypercoagulable and additional vascular causes were excluded. Although the cause of the calcification remains obscure, we speculate that, similarly to mineralizing microangiopathy, a minor trauma led to stroke in this child. To our knowledge, mineralizing microangiopathy, the well-described entity affecting perforating arteries of the anterior circulation in young children leading to basal ganglia stroke following minor head traumas has not been described in the posterior circulation or in previously healthy school-age children.

A comprehensive model of the development of mental handicap in children treated for acute lymphoblastic leukaemia: A synthesis of the literature

Most clinical studies addressing sequelae in children with leukaemia are not theory-driven. Nonetheless, the role of different mediating biological (e.g. cranial irradiation, chemotherapy) and psychosocial variables (e.g. family functioning) has been empirically acknowledged. In these studies, a cause-effect relationship between biological variables and cognitive deficits, sometimes complex due to multiple agents, has been hypothesised. As for the psychosocial consequences, adaptation to the cancer-related stress has been the main focus, at both the individual and family levels. In this paper, we advocate the use of a global model for the development of handicap, derived from the International Classification of Impairments, Disabilities and Handicaps (ICIDH) by the World Health Organisation. This revised model proposes that handicap is the result of complex interactions between the characteristics of a person’s impairment, disabilities, and the characteristics of the environment. At each of these levels, risk/resilience factors are defined. This means that depending on the environmental obstacles they face, persons with an impairment or a disability may or may not experience a situation creating a handicap which is no longer seen as a stable status resulting from a disease to which the individual must adapt. By reviewing animal and clinical studies, current knowledge pertaining to leukaemia sequelae are integrated into the different levels defined by the model: organic impairment, disabilities, environmental obstacles, and handicap situation. Practical implications for research, policies, and individual treatments, and comparisons with existing models, are also outlined.

A Cross-Sectional Cohort Study of Cerebrovascular Disease and Late Effects After Radiation Therapy for Craniopharyngioma

BACKGROUND

The study objective was to describe radiation-induced vascular abnormalities, stroke prevalence, and stroke risk factors in survivors of childhood craniopharyngioma.

PROCEDURE

Twenty survivors of childhood craniopharyngioma who received radiotherapy (RT) were included in the study. A clinical history, quality of life assessment, cognitive functioning assessment, magnetic resonance angiogram or computed tomography angiogram, fasting lipid profile, and fasting glucose or hemoglobin A1c test were obtained.

RESULTS

Median age at diagnosis was 10.3 years and median age at time of study was 29.0 years. Vascular abnormalities were detected in six (32%) of 19 patients' angiograms (vascular stenosis, decreased artery size, aneurysm, cavernoma, and small vessel disease). Five (25%) of 20 patients experienced a stroke after RT. Median time since RT was 27.8 versus 9.1 years in patients with versus without vascular abnormalities (P = 0.02). A low level of high-density lipoproteiin (HDL) was present in 100% (5/5) of patients who had a post-RT stroke as compared with 13% (2/15) of patients who did not have any post-RT stroke (P = 0.02). Previous stroke had occurred in 0% (0/5) of patients receiving growth hormone (GH) replacement at the time of study, compared to 40% (6/15) of patients who were not receiving GH replacement (P = 0.09).

CONCLUSIONS

Patients with craniopharyngioma treated with RT have a high prevalence of stroke and vascular abnormalities, particularly those with low HDL and longer duration of time since RT. There is a trend to suggest that continual GH replacement may reduce the risk of stroke. These patients should undergo careful monitoring and aggressive modification of stroke risk factors.

Review of cranial radiotherapy-induced vasculopathy

Cranial radiation can impact the cerebral vasculature in many ways, with a wide range of clinical manifestations. The incidence of these late effects including cerebrovascular accidents (CVAs), lacunar lesions, vascular occlusive disease including moyamoya syndrome, vascular malformations, and hemorrhage is not well known. This article reviews the preclinical findings regarding the pathophysiology of late radiation-induced vascular damage, and discusses the clinical incidence and risk factors for each type of vasculopathy. The pathophysiology is complex and dependent on the targeted blood vessels, and upregulation of pro-inflammatory and hypoxia-related genes. The risk factors for adult CVAs are similar to those for patients not exposed to cranial radiotherapy. For children, risks for late vascular complications include young age at radiotherapy, radiotherapy dose, NF1, tumor location, chemotherapy, and endocrine abnormalities. The incidence of late vascular complications of radiotherapy may be impacted by improved technology, therapeutic interventions, and appropriate follow up.

Myelopathy mimicking subacute combined degeneration in a Down syndrome patient with methotrexate treatment for B lymphoblastic leukemia: report of an autopsy case

We report clinicopathological features of a 23-year-old woman with Down syndrome (DS) presenting with subacute myelopathy treated with chemotherapy, including intravenous and intrathecal administration of methotrexate (MTX), and with allogenic bone-marrow transplantation for B lymphoblastic leukemia. Autopsy revealed severe demyelinating vacuolar myelopathy in the posterior and lateral columns of the spinal cord, associated with macrophage infiltration, marked axonal loss and some swollen axons. Pathological changes of posterior and lateral columns were observed from the medulla oblongata to lumbar cord. Proximal anterior and posterior roots were preserved. Cerebral white matter was relatively well preserved. There were no vascular lesions or meningeal dissemination of leukemia. Longitudinal extension of cord lesions was extensive, unlike typical cases of subacute combined degeneration (SACD), but distribution of lesions and histological findings were similar to that of SACD. DS patients show heightened sensitivity to MTX because of their genetic background. Risk factors for toxic myelopathy of DS are discussed, including delayed clearance of MTX despite normal renal function, alterations in MTX polyglutamation and enhanced folic acid depletion due to gene dosage effects of chromosome 21. Alteration of folate metabolism and/or vitamin B12 levels through intravenous or intrathecal administration of MTX might exist, although vitamin B12 and other essential nutrients were managed using intravenous hyperalimentation. To the best of our knowledge, this is the first report of an autopsy case that shows myelopathy mimicking SACD in a DS patient accompanied by B lymphoblastic leukemia. The case suggests a pathophysiological mechanism of MTX-related myelopathy in DS patients with B lymphoblastic leukemia mimicking SACD.

Hypoxia inhibits the spontaneous calcification of bone marrow-derived mesenchymal stem cells

Bone marrow-derived mesenchymal stem cells (BM-MSCs) are the popular seed cells for regenerative medicine, and there has been a rapid increase in the number of BM-MSC-based clinical trials. However, the safety of these cells should also be closely studied. In this study, spontaneous calcification of BM-MSCs from rats was evaluated in normoxia (20% O(2)) without osteogenic medium after continuous culture for 21 days; obvious mineralized nodules were observed, which were positive for Alizarin Red, collagen-I (Col-I), osteocalcin (OC) and alkaline phosphatase (ALP), and mainly consisted of C, O and Ca elements. Interestingly, hypoxia (2% O(2)) significantly inhibited this spontaneous calcification. In addition, the ALP and calcium content of rBM-MSCs were sharply reduced. Based on RT-PCR results, the expression of osteogenic genes (Cbfa1/Runx2, Col-I, ALP, and OC) was reduced compared to that in normoxia. These results demonstrate a natural and unique characterization of rat BM-MSCs in normoxia after continuous culture and highlight the inhibiting effects of hypoxia. Finally, this study contributes to the information regarding the application of BM-MSCs in the regeneration of various tissues.

Central nervous system chemotoxicity during treatment of pediatric acute lymphoblastic leukemia/lymphoma

In the last decades, increasing success rates are being obtained in the chemotherapy of pediatric leukemia and lymphoma. However, the cornerstone of this treatment is still formed by a reduced number of drugs with a highly toxic profile. In particular, central nervous system complications remain a challenging clinical problem, requiring rapid detection and prompt treatment to limit permanent damage. Furthermore, clinicians are often challenged to discriminate between CNS involvement by the disease, toxicity of drugs or infections. This clinically oriented review will help recognize and handle the main neurologic adverse effects induced by chemotherapy in pediatric patients with lymphoblastic leukemia/lymphoma. Different clinical entities and putative drugs involved are discussed in each chapter, with clinical cases illustrating the most relevant and challenging events. In addition, specific clinical-radiological patterns of some of these neurologic events are detailed. Finally, the role of pharmacogenetics, with special focus on those polymorphisms that could help explain the occurrence of neurotoxicity, is also discussed.

Stroke and cerebrovascular complications in childhood cancer survivors

The outcomes for childhood cancer have drastically improved over the last several decades. Previously, irradiation was commonly used for blood-borne (leukemia, lymphoma) cancers and neck and brain tumors. Radiation therapy remains the mainstay of treatment for highly malignant cancers of head and neck and for some primary central nervous system tumors. Unfortunately, radiation therapy has been implicated as a contributor to many late effects of treatment, including cerebrovascular disease from large-vessel vascular injury, stroke, moyamoya, mineralizing microangiopathy, to stroke-like migraine. This review summarizes the pathophysiology of these disorders in relationship to treatment with and without radiation as well as the relevant manifestations of radiation-induced cerebrovascular disease. Patient populations at highest risk and current recommendations for health providers and patient education are emphasized when possible.

Imaging features of acquired pediatric metabolic and toxic white matter disorders

Acquired white matter abnormalities in children may be due to a broad spectrum of disorders, with the most significant related to metabolic and toxic etiologies. Recognition of the imaging appearance of neonatal hypoglycemia, nonketotic hyperglycemia, hyperammonemia, hepatic encephalopathy, and central pontine myelinolysis (CPM) is essential because prompt correction of the underlying metabolic abnormality may limit and, in some cases, reverse the cerebral damage. Toxic leukoencephalopathies encompass disorders caused by iatrogenic administration of pharmacologic agents and radiation therapy, poisoning by household substances, and recreational drug use. Although medication-induced leukoencephalopathies often show a propensity for reversibility of clinical and radiologic findings upon discontinuation of the offending substance, recreational drugs may cause white matter toxicity that often portends a poorer prognosis. Our discussion focuses on the clinical aspects, pathophysiological mechanisms, and imaging features of commonly encountered acquired metabolic and toxic leukoencephalopathies in the pediatric population.

Cerebrovascular disease in childhood cancer survivors: A Children's Oncology Group Report

BACKGROUND

Curative therapy for childhood cancer has dramatically improved over past decades. Therapeutic radiation has been instrumental in this success. Unfortunately, irradiation is associated with untoward effects, including stroke and other cerebrovascular disease (CVD). The Children's Oncology Group (COG) has developed guidelines for screening survivors at risk for persistent or late sequelae of cancer therapy.

OBJECTIVES

This review summarizes the pathophysiology and relevant manifestations of radiation-induced CVD and outlines the specific patient groups at risk for early-onset stroke. The reader will be alerted to the availability of the COG recommendations for monitoring, and, when applicable, specific screening and treatment recommendations will be highlighted.

METHODS

A multidisciplinary task force critically reviewed the existing literature and scored the evidence to establish the current COG guidelines for monitoring health of survivors treated with head and neck irradiation.

RESULTS

Previous head and neck exposure to therapeutic radiation is associated with latent CVD and increased risk for stroke in some patient groups. Common manifestations of radiation-induced CVD includes steno-occlusive disease, moyamoya, aneurysm, mineralizing microangiopathy, vascular malformations, and strokelike migraines.

CONCLUSION

Risk for stroke is increased in survivors of pediatric CNS tumors, Hodgkin lymphoma, and acute lymphoblastic leukemia who received radiation to the brain and/or neck. As the population of survivors ages, vigilance for stroke and cerebrovascular disease needs to continue based on specific exposures during curative cancer therapy.

Massive myelinolytic leukoencephalopathy in a patient medicated with low-dose oral methotrexate for rheumatoid arthritis: an autopsy report

The authors describe a 68-year-old female who developed a rapidly progressing leukoencephalopathy involving the cerebrum and brain stem. The disease appeared during low-dose oral methotrexate (MTX) therapy for rheumatoid arthritis. An extensive clinical investigation discounted other possible causes of white matter lesions. Autopsy identified an uninterrupted severe demyelinating, partially liquefactive necrosis-like lesion in the white matter accompanied by astrogliosis and occasional swollen axons therein. The lesion was generally symmetrical, and distributed throughout the whole cerebral white matter except for the bilateral temporal lobes and the rostral part of the frontal lobes. The internal capsules and cerebral peduncles were spongy, and the central and lateral parts of the pons, especially the transverse cerebellopontine tracts, were affected similarly. It was of note that the lesion was accompanied by neither vascular diseases nor lymphocyte infiltration. Thus, the pathological findings were similar to those of a severe form of central and extrapontine myelinolysis, and clearly different from ordinary MTX leukoencephalopathy reported in patients receiving intrathecal or intravenous MTX therapy, known as "disseminated necrotizing leukoencephalopathy". Another possibility is that synergistic effects of several white-matter-damaging disorders may have contributed to the hitherto unknown lesion. To our knowledge, this is the first autopsy record that describes an oral MTX-associated neurological disorder.

Seizures and epilepsy in oncological practice: causes, course, mechanisms and treatment

There are few data available on the causes and mechanistic basis, outcome and treatment of seizures and epilepsy in people with systemic cancer. Seizures and epilepsy in people with cancers other than primary brain tumours are reviewed here. Articles published in English, which discussed the neurological manifestations and complications of cancer and its treatment, were searched and information on the frequency, aetiology, and course of seizures and epilepsy was extracted. The frequency, aetiology and outcome of seizure disorders in patients with cancer differ from those in the general population. Intracranial metastasis, cancer drugs and metabolic disturbances are the most common causes. Infections, cerebrovascular complications of systemic cancer and paraneoplastic disorders are among the rarer causes of seizures in patients with neoplasms. Several drugs used in the treatment of cancer, or complications arising from their use, can trigger seizures through varied mechanisms. Most drug-induced seizures are provoked and do not require long-term treatment with antiepileptic drugs.

Tumor resection cavity administered iodine-131-labeled antitenascin 81C6 radioimmunotherapy in patients with malignant glioma: neuropathology aspects

INTRODUCTION

The neurohistological findings in patients treated with targeted beta emitters such as (131)I are poorly described. We report a histopathologic analysis from patients treated with combined external beam therapy and a brachytherapy consisting of a (131)I-labeled monoclonal antibody (mAb) injected into surgically created resection cavities during brain tumor resections.

METHODS

Directed tissue samples of the cavity walls were obtained because of suspected tumor recurrence from 28 patients. Samples and clinical follow-up were evaluated on all patients (Group A) based on total radiation dose received and a subset of these (n=18; Group B, proximal therapy subset) who had received external beam therapy within <or=3 months of mAb therapy and undergoing 26 biopsies over 37 months. Histologic outcomes were "proliferative glioma," "quiescent glioma" and negative for neoplasm. Statistical analysis was used to assess the casual relation between total absorbed dose ((131)I-mAb+external beam) and histologic diagnosis.

RESULTS

The lesions observed after (131)I-mAb therapy were qualitatively similar to those reported for other types of radiation therapy; however, the high localized dose rate and absorbed doses produced by the short range of (131)I beta particles seem to have resulted in an earlier necrotic reaction in the tumor bed. Among all 28 (Group A) patients, median survival from tissue analysis after mAb therapy depended on histopathology and total radiation absorbed dose. Median survival for patients with tissue classified as proliferative glioma, quiescent glioma and negative for neoplasm were 3.5, 15 and 27.5 months, respectively. Without categorization, total dose was a significant predictor of survival (P<.002) where patients with higher doses had better prognoses. For example, median survival in patients receiving a total radiation dose greater than 86 Gy was 19 months compared with 7 months for those receiving less than 86 Gy.

CONCLUSIONS

Histopathologic analysis correlated with prognosis. Among all patients (Group A) there was a significant correlation between biopsy outcome, survival, and total radiation absorbed dose. Among the Group B proximal therapy patients, the neuropathologic changes were qualitatively similar to those described for external beam therapy and interstitial brachytherapy.

Growth Retardation and Bilateral Cataracts Followed by Anaplastic Meningioma 23 Years after High-Dose Cranial and Whole-Body Irradiation for Acute Lymphoblastic Leukemia: Case Report and Review of the Literature

We report a case of meningioma diagnosed 23 years after high-dose cranial and whole-body irradiation for the treatment of acute lymphocytic leukemia (ALL). Radiotherapy in this case also caused early radiation injury to the lenses and the pituitary gland, with growth retardation and mineralizing angiopathy. Radiation-induced meningiomas are more commonly malignant, more commonly multiple, and more likely to recur after resection than non-radiation-induced meningiomas. Survivors of childhood ALL treated with high-dose cranial irradiation are at risk both for early radiation injury in radiosensitive organs, such as the lens and pituitary gland, and for the later development of a radiation-induced meningioma.

Radiation as a Nervous System Toxin

Neurotoxicity from radiation can range widely and produce effects that may include (1) small absolute increases in cancer risks, (2) subtle effects on higher level functioning in some individuals, (3) severe cognitive impairment in some individuals, (4) severe focal injury tat may include necrosis or irreversible loss of function, and (5) overwhelming and rapidly fatal diffuse injury associated with high-dose, whole-body exposures. An understanding of the implications of nervous system exposure to radiation can guide efforts in radiation protection and aid in the optimization of the medical uses of radiation.

Mesial temporal sclerosis in acute childhood leukemias

PURPOSE

Although seizures are relatively common in acute childhood leukemias, evolution into epilepsy is rare.

METHODS

We describe three patients with acute leukemias who received chemotherapy. One patient also received cranial irradiation.

RESULTS

All three developed recurrent complex partial seizures after initiation of chemotherapy. Initial neuroimaging performed in two patients was normal. Subsequent neuroimaging in all three revealed mesial temporal sclerosis.

CONCLUSIONS

The association of mesial temporal sclerosis in acute childhood leukemias has not been previously described and may be secondary to antileukemic treatment and recurrent seizures.

Central nervous system-directed therapy in the treatment of childhood acute lymphoblastic leukemia and studies of neurobehavioral outcome: Children's Cancer Group trials

Long-term survival rates in childhood acute lymphoblastic leukemia (ALL) have improved due, in part, to the introduction and subsequent refinements in central nervous system (CNS)-directed therapy. Studies of cognitive, motor, and behavioral functioning, which characterize the patterns and severity of CNS sequelae, are being used increasingly as measurable treatment endpoints. This paper summarizes the advances in CNS-directed therapy derived from Children's Cancer Group randomized therapeutic trials. Results from neurobehavioral outcome studies built upon these trials are also presented. A section of this review is focused on CNS-directed treatments and the neurodevelopmental outcomes of infants diagnosed with ALL, an especially high-risk patient subset. Future studies of neurobehavioral outcome are briefly elaborated in the context of current chemotherapy approaches used in the treatment of childhood ALL.

Neuropsychologic sequelae in the long-term survivors of childhood acute lymphoblastic leukemia

The neurotoxicity of either systemic chemotherapy or central nervous system prophylaxis was studied in 19 children treated for acute lymphoblastic leukemia (ALL). They had completed ALL therapy at least a year before and survived more than 5 years after diagnosis. The duration between age at diagnosis and age at investigation was 8.6 +/- 2.7 years (5-15 years). Neuropsychologic tests, cranial magnetic resonance imaging (MRI), and evoked potentials (EP) were studied. Seventeen healthy siblings were taken as a control group. Emotional evaluation was done using the childhood depression inventory and Beck depression inventory. Cognitive functions were evaluated using Wechsler's Intelligence Scale for Children-Revised (WISC-R) or the Wechsler's Adult Intelligence Scale-Revised (WAIS-R) tests, which were adapted to Turkish children. Performance and total IQ scores (94.0 +/- 16.8 and 92.2 +/- 16.5) were significantly low as compared to the control group (112.1 +/- 18.9 and 105.4 +/- 14.2) (p = .007 and p = .02). Abnormal MRI findings were found in 33.3% (6/18). Three out of 18 patients (16.6%) had abnormal auditory while 5 out of 17 patients (29.5%) displayed abnormal visual EPs. Abnormal findings in MRI, cognitive examination, and electrophysiologic testing were not associated with age at diagnosis, radiotherapy doses, intermediate/high-dose systemic methotrexate administration or central nervous system involvement. But more patients must be studied to demonstrate discrete outcomes of neurotoxicity in long-term survivors of childhood leukemia.

[Late effects of radiotherapy in children]

Although most pediatric tumors can be cured with lower doses of radiation than their adult counterparts, long-term radiation-induced complications and sequelae remain a major concern both in terms of frequency and intensity. Most of them have been extensively documented in the pre-chemotherapeutic era like those affecting bone, cartilage and soft tissue growth or CNS and endocrine glands. More recently the emphasis has been put on the apparent increasing incidence of reported second malignancies. This could have been favored by the chemo-radiation combinations used in most children but also has been made possible mainly by the extensive follow-up of the increasing cohort of cured children.

CNS late effects after ALL therapy in childhood. Part I: Neuroradiological findings in long-term survivors of childhood ALL--an evaluation of the interferences between morphology and neuropsychological performance. The German Late Effects Working Group

The effect of cranial irradiation on possible therapy-induced morphological central nervous system (CNS) side effects of children cured from acute lymphoblastic leukemia (ALL) is controversially discussed. In a retrospective multicenter study, 118 former ALL patients in first continuous remission were investigated using cranial computerised tomography (CCT) or magnetic resonance imaging (MRI) scans to evaluate CNS related impairments. Corresponding to the different kinds of CNS prophylaxis, the patient sample was divided: group A (n = 39) receiving intrathecal methotrexate (ITMTX) and systemical medium-high-dose methotrexate (SMHDMTX), group B (n = 41) cranial irradiated (in mean 16.8 Gy) and administering ITMTX and SMHDMTX, group C (n = 38) irradiated (in mean 17.1 Gy) and getting ITMTX. Pathologic scans showed atrophy, leukoencephalopathy, calcifications or grey matter changes. These findings were compared with the neuropsychological test results. Abnormal MRI or CCI scans were found in 61/118 patients (51.7%). Fifteen belonged to group A (38.5%), 23 to B (56.1%) and 23 to C (60.5%). Patients with definite CNS changes show reduced neuropsychological test results. The prevalence of brain alterations seems to appear twice increased after lengthening the posttherapeutic interval in irradiated patients as in nonirradiated patients. Irradiated patients as an age younger than 2 years at diagnosis may show a lower prevalence for developing CNS alterations. CNS alterations are not sex-related. Children treated with cranial irradiation in combination with SMHDMTX and/or ITMTX were at greater risk of developing morphological brain alterations than patients with chemotherapy alone. These alterations are partly correlated with reduced neuropsychological performances and seem to stay with a longer posttherapeutic interval.

Neuropsychological function in adults after high dose fractionated radiation therapy of skull base tumors

PURPOSE

To evaluate the long term effects of high dose fractionated radiation therapy on brain functioning prospectively in adults without primary brain tumors.

METHODS AND MATERIALS

Seventeen patients with histologically confirmed chordomas and low grade chondrosarcomas of the skull base were evaluated with neuropsychological measures of intelligence, language, memory, attention, motor function and mood following surgical resection/biopsy of the tumor prior to irradiation, and then at about 6 months, 2 years and 4 years following completion of treatment. None received chemotherapy.

RESULTS

In the patients without tumor recurrence or radiation necrosis, there were no indications of adverse effects on cognitive functioning in the post-acute through the late stages after brain irradiation. Even in patients who received doses of radiation up to 66 Cobalt Gy equivalent through nondiseased (temporal lobe) brain tissue, memory and cognitive functioning remained stable for up to 5 years after treatment. A mild decline in psychomotor speed was seen in more than half of the patients, and motor slowing was related to higher radiation doses in midline and temporal lobe brain structures.

CONCLUSION

Results suggest that in adults, tolerance for focused radiation is relatively high in cortical brain structures.

Radiosurgery for cerebral AVMs in children and adolescents: the neurobehavioral outcome

Eight patients, ranging in age from 9 to 18 years, were treated for arteriovenous malformations using gamma knife radiosurgery and were evaluated an average of 6 years after treatment to record potential effects of radiosurgery on cognitive and neuropsychological performance. Tests for general intelligence, nonverbal intelligence, memory and its components, and attention performance were administered to patients and compared with test results of age-matched siblings or first cousins. No statistically significant difference was found between the performance of patients and controls in any of the tests administered. Additionally, a specially designed questionnaire completed by the patients, their parents, and their teachers revealed that the patients' emotional and relational behavior was stable and unchanged after treatment. No correlation was found between the neurocognitive test performance and the lesion volumes irradiated, but the lesion site was found to contribute to the type of deficit recorded after treatment. The less invasive nature of the radiosurgical approach, combined with the brevity or absence of hospitalization, presumably contributed to the patients successful physical, mental, and emotional recovery.

Calcifications of the basal ganglia in children with brain tumours

Calcifications in the basal ganglia have been found in nine (5.4%) of all children treated for any kind of brain tumour in our department. This has occurred over a mean period of 2.8 years after diagnosis. The group of patients has been compared with a group of other children, matched for age, sex, histologic diagnosis and tumour treatment, but without calcifications of the basal ganglia. The groups differ from each other with respect to a significantly higher incidence of hypothyroidism and growth hormone deficiency in the group of children with calcifications in the basal ganglia. Moreover the children with calcifications show a larger IQ-loss. Although the pathogenesis of the calcifications of the basal ganglia is not known, an association of damage to the vascular bed of the basal ganglia due to periods of increased intracranial pressure, together with endocrine deficiencies is discussed. We advise an adequate supplementation in cases of endocrine deficiencies in children treated for brain tumours as early as possible.

Lenńox-Gastaut syndrome associated with leukoencephalopathy

We report a 13-year-old boy with Lennox-Gastaut syndrome (LGS) associated with leukoencephalopathy. He was diagnosed with unclassified acute lymphocytic leukemia at the age of 3 years. After initial chemotherapy, he received intravenous methotrexate (total dosage 1,035 mg), intrathecal methotrexate (total dosage 221 mg), and whole brain irradiation (2,400 cGy). From about the age of 8 years, he developed slurred speech, hyperactivity, and mental deterioration. Cranial CT revealed calcification of the subcortical white matter. At age 9 years, he exhibited tonic seizures and atonic seizures. EEG showed diffuse slow spike-wave discharges, which are characteristic of LGS. Although multiple antiepileptic drugs have been prescribed, the frequency of seizures remains unchanged and his mental state is becoming progressively worse.

Minor changes on cranial MRI during treatment in children with acute lymphoblastic leukaemia

Cranial MRI was used to study treatment-related changes in children undergoing therapy for acute lymphoblastic leukaemia (ALL) or lymphoma. Nineteen children (18 with ALL, 1 with lymphoma) underwent MRI at the beginning of treatment and at intervals during it, to a total of 105 imaging studies and a minimum of 3 per case. Nine patients had finished all therapy, all received consolidation treatment. No patient had central nervous system (CNS) leukaemia at diagnosis or developed a CNS relapse. Mild treatment-related white matter changes were observed in only 2 patients after consolidation therapy with three 5 g/m2 pulses of intravenous methotrexate. Transient enlargement of the ventricles and cortical sulci was observed in 13 patients, always temporally related to steroid treatment. These preliminary data suggest that treatment-related white matter changes are rare and no routine MRI follow-up is needed during treatment in asymptomatic children after a baseline assessment.

Cerebro-vasculopathy and malignancy: catastrophic complications of radiotherapy for optic nerve glioma in a von Recklinghausen neurofibromatosis patient

The authors report a unique case of a patient with intraorbital optic nerve glioma and von Recklinghausen neurofibromatosis who developed cerebro-vasculopathy and malignant transformation in the orbit 18 months after radiotherapy treatment. The case is an important reminder of the possibly increased susceptibility of von Recklinghausen neurofibromatosis patients to the complications of radiotherapy.

Central nervous system toxicity of cancer therapy in children

Cancer treatment of the central nervous system has contributed positively to long-term disease-free survival from childhood cancers such as acute leukemia and medulloblastoma. However, intrathecal chemotherapy and whole brain radiation are associated with acute, subacute, and delayed toxicities. The purpose of this review article is to summarize what is known about critical events in prenatal and postnatal brain development; the pathophysiology of radiation and chemotherapy neurotoxicity and clinical manifestations and risk factors for acute, subacute, and delayed toxicities. The importance of long-term follow-up and for multidisciplinary interventions that focus on prevention as well as management of identified problems are addressed.

Mineralizing microangiopathy: CT and MRI

Mineralizing microangiopathy, a distinctive histopathologic process involving the microvasculature of the central nervous system (CNS), is usually seen following combined radiation and chemotherapy for the treatment of CNS neoplasms in childhood. CT typically demonstrates calcification within the basal ganglia and subcortical white matter. The areas of calcification may give paradoxically increased signal on T1-weighted MRI due to a surface-relaxation mechanism, and decreased signal on T2-weighted images.

Radiation response of the central nervous system

This report reviews the anatomical, pathophysiological, and clinical aspects of radiation injury to the central nervous system (CNS). Despite the lack of pathognomonic characteristics for CNS radiation lesions, demyelination and malacia are consistently the dominant morphological features of radiation myelopathy. In addition, cerebral atrophy is commonly observed in patients with neurological deficits related to chemotherapy and radiation, and neurocognitive deficits are associated with diffuse white matter changes. Clinical and experimental dose-response information have been evaluated and summarized into specific recommendations for the spinal cord and brain. The common spinal cord dose limit of 45 Gy in 22 to 25 fractions is conservative and can be relaxed if respecting this limit materially reduces the probability of tumor control. It is suggested that the 5% incidence of radiation myelopathy probably lies between 57 and 61 Gy to the spinal cord in the absence of dose modifying chemotherapy. A clinically detectable length effect for the spinal cord has not been observed. The effects of chemotherapy and altered fractionation are also discussed. Brain necrosis in adults is rarely noted below 60 Gy in conventional fractionation, with imaging and clinical changes being observed generally only above 50 Gy. However, neurocognitive effects are observed at lower doses, especially in children. A more pronounced volume effect is believed to exist in the brain than in the spinal cord. Tumor progression may be hard to distinguish from radiation and chemotherapy effects. Diffuse white matter injury can be attributed to radiation and associated with neurological deficits, but leukoencephalopathy is rarely observed in the absence of chemotherapy. Subjective, objective, management, and analytic (SOMA) parameters related to radiation spinal cord and brain injury have been developed and presented on ordinal scales.

Late cranial MRI after cranial irradiation in survivors of childhood cancer

We carried out MRI on 43 survivors of childhood cancer after different treatment protocols with or without cranial radiotherapy. They were free of disease, therapy having been discontinued 2-20 years earlier. Treatment had been for various malignancies, excluding brain tumours; 27 had received cranial irradiation for acute lymphoblastic leukaemia (ALL) or lymphoma. Two asymptomatic young women treated for ALL had falx meningiomas. White matter changes, low intensity foci (representing calcification or old haemorrhage) and heterogeneous intensity focic old haemorrhages) were seen only in patients who had undergone radiotherapy. Because of the possibility of benign, potentially curable brain tumours occurring after cranial irradiation, it may be wise to carry out occasional cranial imaging in the follow-up of these patients. No routine imaging follow-up is needed after chemotherapy alone.

Acute lymphoblastic leukaemia: language deficits in children post-treatment

The language abilities of a group of 22 children (aged between 5 years and 17 years, 9 months) treated for acute lymphoblastic leukaemia (ALL) were investigated and compared with those of a group of non-neurologically impaired, age- and sex-matched controls. The language test battery included an age-appropriate measure from the Test of Language Development (TOLD) series, consisting of either the Test of Adolescent Language (TOAL--2), or the Test of Language Development--Intermediate or --Primary (TOLD--I or --P); the timed subtests of the Clinical Evaluation of Language Function (CELF); the Boston Naming Test; and one of either the Token Test or the Token Test for Children, depending on the age of the subject. As a group, the leukaemia subjects performed significantly worse than the controls on the TOAL--2, TOLD--I, TOLD--P, Token Test, and Boston Naming Test. The need for post-treatment monitoring of the language abilities of children treated for ALL to enable early remediation of areas of deficit is highlighted.

Radiotherapy for pediatric brain stem glioma: radiation dose, response, and survival

An analysis of 39 patients under 20 years of age with brain stem glioma treated with radiotherapy between 1977 and 1991 was undertaken. Twenty-eight (71.2%) of the patients responded well to initial radiotherapy, and 11 (28.8%) responded poorly. Median survival for the total patient population was 10 months. Response rates and median survivals were influenced by radiation dose: 45.5% and 9 months at doses less than 4499 cGy (n = 11), 83.3% and 13 months at doses between 4500 and 5499 cGy (n = 12), 66.7% and 11.5 months at doses between 5500 and 6499 cGy (n = 9), and 100% and 10 months at doses more than 6500 cGy (n = 7). Multivariate analysis revealed the response to initial radiotherapy was the only predictor of survival with radiation doses up to 6499 cGy. Four of the patients who responded well demonstrated radiological and/or histological calcification within or around the tumor at the time of clinical deterioration. Radiation injury was confirmed in two autopsy cases. The possibility that intratumoral radiation injury causes clinical deterioration is suggested.

Vascular malformation with radiation vasculopathy after treatment of chiasmatic/hypothalamic glioma

Chiasmatic/hypothalamic gliomas usually are histologically benign astrocytomas that may recur many years after diagnosis and treatment. Three children with chiasmatic/hypothalamic gliomas who were treated at the authors' institution returned 9.5, 11.5, and 2 years, respectively, after radiation therapy (RT) because visual and neurologic deterioration developed. Neuroradiographic studies, including arteriography in two of the patients, showed large mass lesions. These were presumed to be recurrence of tumor, and chemotherapy was administered. Pathologic examination of two children who died and of the third who had a biopsy revealed only a minimal amount of residual, histologically benign astrocytoma, whereas the bulk of the specimen consisted of numerous vessels of variable size. These probably represented incorporation of the rich vasculature in the chiasmal region into the tumor, which underwent degeneration secondary to RT. Radiographic methods did not distinguish progressive tumor growth from the vasculopathy and led to inappropriate clinical diagnoses and treatment.

CNS prophylaxis of childhood leukemia: what are the long-term neurological, neuropsychological, and behavioral effects?

Current medical treatments for childhood acute lymphoblastic leukemia (ALL) have improved the outlook to where more than 50% can be expected to survive five years or more. The use of CNS prophylaxis has contributed in a significant way to these improved survival statistics by reducing the likelihood of CNS relapses. The literature relating to the potential adverse psychological consequences of CNS prophylaxis, which include cranial radiation therapy (CRT), is reviewed and analyzed. The majority of published papers of children in first remission report that CNS prophylaxis, which include both CRT and intrathecal methotrexate, results in a variety of learning problems in many children who were younger than age 5 when treated. The available literature on the social, emotional, and educational sequelae of childhood ALL is also reviewed.