Long-term neuropsychologic sequelae of childhood leukemia: correlation with CT brain scan abnormalities

Young Adult Cancer Survivorship: Recommendations for Patient Follow-up, Exercise Therapy, and Research

Survivors of adolescent and young adult cancers (AYAs) often live 50 to 60 years beyond their diagnosis. This rapidly growing cohort is at increased risk for cancer- and treatment-related 'late effects' that persist for decades into survivorship. Recognition of similar issues in pediatric cancer survivors has prompted the development of evidence-based guidelines for late effects screening and care. However, corresponding evidence-based guidelines for AYAs have not been developed. We hosted an AYA survivorship symposium for a large group of multidisciplinary AYA stakeholders (approximately 200 were in attendance) at Princess Margaret Cancer Centre (Toronto, Ontario, Canada) to begin addressing this disparity. The following overview briefly summarizes and discusses the symposium's stakeholder-identified high-priority targets for late effects screening and care and highlights knowledge gaps to direct future research in the field of AYA survivorship. This overview, although not exhaustive, is intended to stimulate clinicians to consider these high-priority screening and care targets when seeing survivors in clinical settings and, ultimately, to support the development of evidence-based late effects screening and care guidelines for AYAs.

Consistent Physical Activity and Future Neurocognitive Problems in Adult Survivors of Childhood Cancers: A Report From the Childhood Cancer Survivor Study

PURPOSE

To investigate longitudinal associations between physical activity (PA) and neurocognitive problems in adult survivors of childhood cancer.

METHODS

A total of 12,123 5-year survivors diagnosed between 1970 and 1999 (median [range] age at diagnosis, 7 [0-21] years, time since diagnosis at baseline, 16 [6-30] years) and 720 siblings self-reported PA and neurocognitive problems. PA was collected at baseline, and PA and neurocognitive data were obtained 7 (1-12) years and 12 (9-14) years later. PA consistency was defined as any combination of ≥ 75 minutes of vigorous or 150 minutes of moderate activity per week on all surveys. Multiple linear regressions, conducted separately for CNS and non-CNS survivors, identified associations between PA consistency and neurocognitive outcomes (expected mean, 50; standard deviation [SD], 10). Mediating effects of body mass index (BMI) and chronic health conditions (CHCs) were evaluated.

RESULTS

Survivors were less likely than siblings to report consistent PA (28.1% v 33.6%) and more likely to report problems in Task Efficiency (T-scores mean ± SD: siblings, 50.0 ± 0.4; CNS, 61.4 ± 0.4; non-CNS, 53.3 ± 0.3), Emotion Regulation (siblings, 51.4 ± 0.4; CNS, 54.5 ± 0.3; non-CNS 53.4 ± 0.2), and Memory (siblings, 50.8 ± 0.4; CNS, 58.9 ± 0.4; non-CNS, 53.5 ± 0.2; all P < .001). Survivors of CNS cancers (52.8 ± 0.3) also reported poorer Organization than siblings (49.9 ± 0.4; P < .001). After adjusting for age at diagnosis, age at questionnaire, emotional distress, and cancer treatment exposures, consistent PA was associated with fewer neurocognitive problems compared with consistent inactivity for both CNS and non-CNS groups (T-score differences ranging from -7.9 to -2.2) and larger neurocognitive improvements over time (-6.0 to -2.5), all P ≤ .01. BMI and severe CHCs partially mediated the PA-neurocognitive associations, but the mediation effects were small (change in β ≤ 0.4).

CONCLUSION

Adult survivors of childhood cancer who report more consistent PA have fewer neurocognitive problems and larger improvements in these concerns many years after treatment.

Progress and Prospects in Pediatric Leukemia

Pediatric leukemia is the single most common malignancy affecting children, representing up to 30% of all pediatric cancers. Dramatic improvements in survival for acute lymphoblastic leukemia (ALL) have taken place over the past 4 decades with outcomes approaching 90% in the latest studies. However, progress has been slower for myeloid leukemia and certain subgroups like infant ALL, adolescent/young adult ALL, and relapsed ALL. Recent advances include recognition of molecularly defined subgroups, which has ushered in precision medicine approaches. We discuss the current understanding of the biology of the various childhood leukemias, recent advances in research, and future challenges in this field.

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.

Psychiatric and psychosocial challenges in patients undergoing haematopoietic stem cell transplants

Haematological malignancies are often treated with haematopoietic stem cell transplants (HSCT). The disease and its treatment are challenging and life threatening, as they not only affect the recipients, but also their families. This review highlights the available data on the psychological, psychiatric and social impact of these illnesses and their treatment on recipients and families. There are robust data that correlate HSCT with emotional distress, as emotional and physical functioning significantly affect quality of life. Psychiatric co-morbidity including anxiety, depression, adjustment and post-traumatic stress disorder, delirium and cognitive deficits have been reported at different stages in the transplant process. This review will highlight the psychosocial and clinical research findings relevant to HSCT patients and will summarize recommendations for future psychosocial research in this population.

Symptoms of attention-deficit/hyperactivity disorder in long-term survivors of childhood leukemia

BACKGROUND

Survivors of childhood acute lymphoblastic leukemia (ALL) sometimes have clinical features that suggest attention-deficit/hyperactivity disorder (ADHD), though few studies have examined specific symptoms in survivors.

PROCEDURE

Long-term survivors of childhood ALL (n = 161) received a neurological examination, while parents completed rating scales to establish formal criteria for ADHD. Symptom profiles were generated and compared across demographic and treatment characteristics, as well as medical tests associated with brain pathology.

RESULTS

Prevalence rates of ADHD were similar in survivors (10.5%) compared to those reported in the general population (7-10%). However, 25.5% of survivors reported symptoms that impair functioning in multiple settings, with attention problems being most common. These symptoms were associated with cranial radiation therapy (CRT) (mean inattentive symptoms [SD] = 3.6 [3.19] for group treated with CRT vs. 1.6 [2.40] for non-CRT group, P = 0.0006), and survivors who demonstrated impaired anti-saccades during the neurologic exam (mean inattentive symptoms [SD] = 3.4 [3.29] for those with impaired anti-saccades vs. 1.4 [2.41] for those with normal anti-saccades; P = 0.0004).

CONCLUSIONS

The presence of a neurologically-based phenotype of attention problems in survivors of leukemia that is not fully captured by the syndrome of ADHD suggests that treatments specific to childhood ALL should be explored.

Long-term neurocognitive outcomes in young adult survivors of childhood acute lymphoblastic leukemia

Five-year survival rates of childhood acute lymphoblastic leukemia (ALL) exceed 80% due to central nervous system-directed treatment including cranial radiation (CRT) and chemotherapy. However, these treatments are associated with neurocognitive compromise, the extent of which is correlated with higher dose and younger age at treatment. The aims of this study were to explore long-term neurocognitive outcomes in adult survivors of childhood ALL, and to identify measures sensitive to neurotoxicity in long-term survivors. We examined 24 adults who received 18 Gy CRT and chemotherapy for treatment of ALL between ages 2 and 15 years (median, 5.5). Time since diagnosis ranged from 6 to 26 years (median, 16.6). Younger age at diagnosis and longer time since diagnosis were associated with lower scores on a computerized battery that requires speed and accuracy across a number of domains (MicroCog), and other standardized neurocognitive tests. When compared with population norms, MicroCog indices were below average in survivors diagnosed with ALL before age 5, but only the reasoning/calculation index was below average in survivors diagnosed with ALL after age 5. In contrast, intelligence quotient (IQ) scores were average. In addition to confirming earlier studies showing that younger children are more vulnerable to treatment-related neurotoxicity, here we show that deficits exist many years post treatment even with a relatively lower dose of CRT, and that these deficits are especially evident on tasks involving rapid processing of information.

Neurodevelopmental sequelae of pediatric acute lymphoblastic leukemia and its treatment

This review will describe the neurocognitive outcomes associated with pediatric acute lymphoblastic leukemia (ALL) and its treatment. The literature is reviewed with the aim of addressing methodological issues, treatment factors, risks and moderators, special populations, relationship to neuroimaging findings, and directions for future research. It is concluded that neurocognitive outcomes for the majority of children with standard-risk ALL treated according to current chemotherapy protocols is relatively good, but subgroups of children are more significantly compromised. As medical treatments advance and survival rates continue to improve, neurocognitive outcomes and other quality of life indicators will become increasingly important. Preventing or ameliorating treatment-related neuropsychological sequelae represents the next major challenge in pediatric ALL.

Progressive declines in neurocognitive function among survivors of hematopoietic stem cell transplantation for pediatric hematologic malignancies

Neurocognitive function of pediatric patients is of great concern after hematopoietic stem cell transplantation (HSCT). We evaluated the neurocognitive function of pediatric patients pre-HSCT, 1, 3, and 5 years post-HSCT. All patients had a hematologic malignancy and received therapy to their central nervous system. Healthy siblings were tested as a comparison group. Pediatric patients with a hematologic malignancy did not have a significant decrease in their cognitive function before HSCT compared with their siblings except in areas of academic achievement. Our study population had significant declines in visual motor skills and memory test scores within the first year post-HSCT. By 3 years post-HSCT, there was an improvement in the visual motor development scores and memory scores, but there were new deficits in verbal skills. By 5 years post-HSCT, there were progressive declines in verbal skills (P=0.005), performance skills (0.04), and new deficits seen in long-term verbal memory scores (0.04). On the basis of the raw scores, most of these tests showed that patients had an inability to acquire new skills at a rate comparable to their age-matched healthy peers. However, long-term memory scores showed definite declines. The greatest decline in neurocognitive function occurred in those patients who received cranial irradiation either as part of their initial therapy or as part of their HSCT conditioning. Pediatric patients who received HSCT for hematologic malignancies have neurocognitive deficiencies that are both acute and chronic. Although some patients have acute deficits that appear and improve over time, other patients have progressive declines in neurocognitive function that are chronic.

Quantitative morphologic evaluation of magnetic resonance imaging during and after treatment of childhood leukemia

INTRODUCTION

Medical advances over the last several decades, including CNS prophylaxis, have greatly increased survival in children with leukemia. As survival rates have increased, clinicians and scientists have been afforded the opportunity to further develop treatments to improve the quality of life of survivors by minimizing the long-term adverse effects. When evaluating the effect of antileukemia therapy on the developing brain, magnetic resonance (MR) imaging has been the preferred modality because it quantifies morphologic changes objectively and noninvasively.

METHOD AND RESULTS

Computer-aided detection of changes on neuroimages enables us to objectively differentiate leukoencephalopathy from normal maturation of the developing brain. Quantitative tissue segmentation algorithms and relaxometry measures have been used to determine the prevalence, extent, and intensity of white matter changes that occur during therapy. More recently, diffusion tensor imaging has been used to quantify microstructural changes in the integrity of the white matter fiber tracts. MR perfusion imaging can be used to noninvasively monitor vascular changes during therapy. Changes in quantitative MR measures have been associated, to some degree, with changes in neurocognitive function during and after treatment.

CONCLUSION

In this review, we present recent advances in quantitative evaluation of MR imaging and discuss how these methods hold the promise to further elucidate the pathophysiologic effects of treatment for childhood leukemia.

Comparing attentional skills in children with acquired and developmental central nervous system disorders

Attentional impairments in children occur in the context of both developmental and acquired disorders involving the central nervous system (CNS) and may have implications for ongoing development, potentially impeding cognitive, educational, and behavioral functions. Using a continuous performance paradigm (CPT), this study compared attentional profiles of children with developmental and acquired conditions impacting on the CNS: (i) attention deficit-hyperactivity disorder (ADHD: n=27); (ii) moderate traumatic brain injury (TBI: n=41); (iii) acute lymphoblastic leukemia (n=31); and (iv) insulin-dependent diabetes mellitus (n=39). A healthy control group (n=46) was also examined. Groups were compared on measures of sustained attention, selective attention, and response inhibition. In addition, measures of performance variability and deterioration and processing speed were examined. Results showed that children with ADHD exhibited global and severe attentional impairments in contrast to all other groups. Children with moderate TBI displayed mild attentional difficulties, restricted to selective and sustained attention domains. In conclusion, although CPT parameters differentiated the ADHD group from all others, a disorder-specific profile was not observed.

Delayed neurotoxicity associated with therapy for children with acute lymphoblastic leukemia

Most children diagnosed today with acute lymphoblastic leukemia (ALL) will be cured. However, treatment entails risk of neurotoxicity, causing deficits in neurocognitive function that can persist in the years after treatment is completed. Many of the components of leukemia therapy can contribute to adverse neurologic sequelae, including craniospinal irradiation, nucleoside analogs, corticosteroids, and antifolates. In this review, we describe the characteristic radiographic findings and neurocognitive deficits seen among survivors of childhood ALL. We summarize what is known about the pathophysiology of delayed treatment-related neurotoxicity, with a focus on the toxicity resulting from pharmacologic disruption of folate physiology within the central nervous system. Finally, we suggest testable strategies to ameliorate the symptoms of treatment-related neurotoxicity or decrease its incidence.

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.

BOLD responses to visual stimulation in survivors of childhood cancer

Children surviving certain cancers have a high incidence of cognitive deficits caused by central nervous system (CNS) disease or treatments directed at the CNS. To establish the feasibility of using blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) to study cognitive deficits in survivors of childhood cancer, we tested the hypothesis that this population has the same BOLD response to visual stimulation as healthy subjects. We used BOLD fMRI to measure spatial and temporal patterns of brain activity after brief visual stimulation in 16 survivors of childhood cancer, 11 age-similar healthy siblings of survivors, and 16 healthy adults. Functional data for the survivors were analyzed with two general linear models, one used a canonical hemodynamic response function (HRF) and the other used a Fourier set as basis functions. The measured BOLD signal and brain activation patterns were similar in the survivors with both models. The BOLD signal for survivors was qualitatively similar in timing and shape, but there were significant quantitative differences as compared with healthy subjects. The activation was normally located in the primary visual cortex in 13 survivors, but the activation volume was significantly smaller in brain tumor survivors than in other groups. These findings demonstrate the feasibility of using BOLD fMRI to investigate brain function in survivors of childhood cancer. However, fMRI studies in this population must take into account effects of quantitative differences in their BOLD responses as compared to healthy subjects.

Neurocognitive Interventions for Children and Adolescents Surviving Cancer

BACKGROUND

It is well recognized that many cures for childhood leukemia and brain tumors entail some relatively permanent neurocognitive and psychological costs to the patient and family. As cure rates have improved over the past three decades, increasing efforts have been directed toward reducing treatment-related late effects.

OBJECTIVE

The particular focus of this review will be on interventions for the neuropsychological late effects associated with the treatment of acute lymphoblastic leukemia (ALL) and malignant brain tumors.

SUMMARY

We will first briefly review current approaches to the medical treatment of ALL and brain tumors to provide an appreciation of potential sources of brain injury. We will then summarize the existing literature on types of neuropsychological deficits found among survivors, with special attention to variables that place some children at greater risk. Then, there will be a discussion of approaches to intervention for these deficits-specifically, cognitive remediation, pharmacology, and ecological alterations in the classroom. Finally, we will present directions for future research in the field.

A critical review of the clinical effects of therapeutic irradiation damage to the brain: the roots of controversy

We critically examined the damaging affects of therapeutic irradiation by comparing results from cross-disciplinary studies of early- and late-delayed radiotherapy effects. Focus is attained by concentrating on clinical treatment issues (volume of brain, dose, timing of effects, age, modality types, and stereotactic treatment techniques), rather than on methodological means or problems, which is necessary to understand the mechanisms and characteristics of radiotherapy-induced behavioral dysfunction including cognition. We make observations and hypotheses about the actual risks from radiotherapy that could be informative in the treatment decision process, and which may lessen the concerns of some patients and their families about the risks they take when receiving radiation. Conditions that predispose to radiation injury are reviewed: (1) higher doses even to part of the brain versus lower doses to the whole brain, (2) combined treatment modalities, (3) malignancy itself, (4) radiation early during postnatal brain development, and (5) late-delayed effects (more than 3 years posttreatment). Current neurocognitive frameworks for understanding cognitive change over time in children and adults are summarized, along with the literature on effects of brain tumors and treatment on depression. No studies have as yet identified candidate brain regions that are more sensitive to radiotherapy. Two studies have provided early, preliminary evidence for a specific vulnerability of visual attention/memory to the early stage of late radiation damage. Furthermore, radiation effects appear severe only in a minority of patients. Risk is related to direct and indirect effects of cancer type, concurrent clinical factors, and premorbid risk factors.

MRI morphometric and neuropsychological correlates of long-term memory in survivors of childhood leukemia

BACKGROUND

Long-term survivors of acute lymphoblastic leukemia (ALL) are reported to have post-treatment neurological changes as well as neuropsychological changes. Few studies have investigated the relationship between magnetic resonance imaging (MRI) volumetric measurements of brain regions of interest and cognitive functioning. This study examined the relationship between hippocampal volumes and long-term memory abilities in survivors of ALL.

PROCEDURE

Ten survivors of ALL and ten matched controls underwent MRI acquisition. The participants completed a battery of tests measuring both visual and verbal long-term memory. Volumetric measurements of the hippocampus were obtained by consecutive manual tracing using the NIH Image 1.52 program. Estimates of whole brain volume were also obtained.

RESULTS

No significant group differences were found in right or left hippocampi. Nor were there significant differences between the two groups on measures of long-term memory. Correlations between volumetric measurements of the hippocampus and measures of long-term memory were non-significant.

CONCLUSIONS

Our hypothesis of deficits in both long-term memory and its neural substrates was not supported. It was concluded that the hippocampus, as an early developing structure, may be less vulnerable to chemotherapy treatment. Children surviving ALL are able to retain and retrieve once learned information comparable with peers.

Long-term cognitive outcome, brain computed tomography scan, and magnetic resonance imaging in children cured for acute lymphoblastic leukemia

BACKGROUND

Prevention of meningeal recurrence achieved by intrathecal methotrexate (MTX) and systemic chemotherapy is part of standard acute lymphoblastic leukemia (ALL) treatment. Cranial irradiation has been a routine part of past protocol treatment but is currently reserved only for select subsets of patients. Central nervous system (CNS) prophylaxis may cause brain abnormalities such as intracerebral calcifications, cerebral atrophy, and white matter alterations. In addition, long-term neuropsychologic sequelae following CNS prophylaxis have been investigated marginally in children cured for ALL.

METHODS

To explore possible correlations between neuroimaging findings and neuropsychologic outcome, we used detailed cognitive tests to evaluate 21 children with ALL who received cranial irradiation (range, 18-24 Gy) plus intrathecal MTX as CNS prophylaxis. All children were followed prospectively once a year by cerebral computed tomographic scan and magnetic resonance imaging. All patients had continuous complete disease remission for at least 4 years and cognitive tests were performed after neuroradiologic examinations.

RESULTS

White matter abnormalities were associated with poor performance only in a task exploring visual motor integration in about 50% of patients. Intracerebral calcifications correlate with the number of intrathecal MTX doses and with low scores in total intellectual quotient, performance intellectual quotient, and significant impairment in attention and visual motor integration tests. Girls are more vulnerable to the effects of CNS prophylaxis, whereas age at treatment and radiotherapy dose are not relevant to neuropsychologic outcome.

CONCLUSIONS

Our results indicate the need for careful follow-up of children's cognitive abilities because global intellectual measures often fail to detect specific disorders that may cause learning difficulties. Moreover, as the clinical implications of neuroimaging findings are often limited, periodic extensive evaluation by specific neurocognitive tests of mental abilities is recommended to detect early signs of cognitive impairment.

Excellent therapeutic efficacy and minimal late neurotoxicity in children treated with 18 grays of cranial radiation therapy for high-risk acute lymphoblastic leukemia: a 7-year follow-up study of the Dana-Farber Cancer Institute Consortium Protocol 87-01

BACKGROUND

In the current study, the authors evaluated late neuropsychologic effects 7 years after diagnosis and the long-term survival in a cohort of patients treated for high-risk childhood acute lymphoblastic leukemia (ALL) with cranial radiation therapy. Efficacy and toxicity were evaluated in relation to patient age at diagnosis (age < or > or = 36 months).

METHODS

Two hundred and one patients treated for high-risk ALL on the Dana-Farber Cancer Institute Consortium Protocol 87-01 were included, 147 of whom were in continuous complete disease remission and were eligible for cognitive testing. Sixty-one patients consented to undergo testing. All patients received 18 grays (Gy) of cranial radiation as a component of central nervous system treatment.

RESULTS

For all 201 patients, the 5-year overall survival (% +/- the standard error) was 82% +/- 2 and the 5-year event-free survival (% +/- the standard error) was 75% +/- 3. Only two patients developed a central nervous system recurrence. Intelligence quotient (IQ) and memory were at the expected mean for age, but performance on a complex figure drawing task was found to be reduced. Children who were age < 36 months at the time of diagnosis were found to have an IQ in the average range, but showed verbal deficits.

CONCLUSIONS

The results of the current study demonstrate excellent efficacy of therapy and relatively limited late neurotoxicity on a childhood ALL therapy protocol in which all evaluated patients had received 18 Gy of cranial radiation. Efficacious therapy that includes cranial radiation does not appear to necessarily incur a heightened risk for significant cognitive impairment.

Immediate neurocognitive effects of methylphenidate on learning-impaired survivors of childhood cancer

PURPOSE

To test if methylphenidate (MPH) has an objective beneficial effect on immediate performance on tests of neurocognitive functions among learning-impaired survivors of childhood acute lymphoblastic leukemia (ALL) and malignant brain tumors (BT).

PATIENTS AND METHODS

From July 1, 1997 through December 31, 1998, 104 long-term survivors of childhood ALL or a malignant BT completed neurocognitive screening for learning impairments and concurrent problems with sustained attention. Eligibility criteria for the MPH trial included an estimated intelligence quotient greater than 50, academic achievement in the 16(th) percentile or lower for age in reading, math, or spelling, and an ability to sustain attention on a computerized version of the Conners' Continuous Performance Test (CPT) in the 16(th) percentile or lower for age and sex. Of the 104, 32 (BT, n = 25; ALL, n = 7) were eligible on the basis of these a priori criteria for a randomized, double-blinded, placebo-controlled trial of MPH. The patients ingested a placebo (lactose) or MPH (0.6 mg/kg; 20 mg maximum) and repeated selected portions of the screening battery 90 minutes later.

RESULTS

Compared to the 17 patients randomized to the placebo group, the 15 patients randomized to the MPH group had a significantly greater improvement on the CPT for sustained attention (errors of omission, P =.015) and overall index (P =.008) but not for errors of commission (indicative of impulsiveness) nor reaction times. A trend for greater improvement in the MPH group on a measure of verbal memory failed to reach statistical significance. No trend was observed for MPH effectiveness in improving learning of a word association task. No significant side effects from MPH were observed.

CONCLUSION

MPH resulted in a statistically significant improvement on measures of attention abilities that cannot be explained by placebo or practice effects.

Neurobehavioral toxicity of total body irradiation: a follow-up in long-term survivors

PURPOSE

Total body irradiation (TBI) in preparation for bone marrow transplantation (BMT) is a routine treatment of hematological malignancy. A retrospective and a prospective group study of long-term cerebral side effects was performed, with a special emphasis on neurobehavioral toxicity effects.

METHODS AND MATERIALS

Twenty disease-free patients treated with hyperfractionated TBI (14.4 Gy, 12 x 1.2 Gy, 4 days), 50 mg/kg cyclophosphamide, and autologous BMT (mean age 38 years, range 17-52 years; age at TBI 35 years, 16-50 years; follow-up time 32 months, 9-65 months) participated in a neuropsychological, neuroradiological, and neurological examination. Data were compared to 14 patients who were investigated prior to TBI. Eleven patients with renal insufficiencies matched for sex and age (38 years, 20-52 years) served as controls. In a longitudinal approach, neuropsychological follow-up data were assessed in 12 long-term survivors (45 years, 23-59 years; follow-up time 8.8 years, 7-10.8 years; time since diagnosis 10.1 years, 7.5-14.2 years).

RESULTS

No evidence of neurological deficits was found in post-TBI patients except one case of peripheral movement disorder of unknown origin. Some patients showed moderate brain atrophy. Neuropsychological assessment showed a subtle reduction of memory performance of about one standard deviation. Cognitive decline in individual patients appeared to be associated with pretreatment (brain irradiation, intrathecal methotrexate). Ten-years post disease onset, survivors without pretreatment showed behavioral improvement up to the premorbid level.

CONCLUSION

The incidence of long-term neurobehavioral toxicity was very low for the present TBI/BMT regimen.

Cognitive and academic outcome following cranial irradiation and chemotherapy in children: a longitudinal study

Cranial irradiation therapy (CRT) and chemotherapy are associated with neurobehavioural deficits. Many studies have investigated late effects of these treatments, but few have evaluated changes in abilities over time. This study employed a longitudinal design to map abilities following these treatments. Three groups of children were studied: Group 1 (n = 35): children treated with CRT (18 Gy) + chemotherapy, aged 5 years or less at time of diagnosis; Group 2 (n = 19): children treated with chemotherapy alone, aged 5 years or less at time of diagnosis; Group 3 (n = 35): healthy children. All children were aged 7-13 years at time of initial assessment, with no pre-diagnosis history of neurologic, developmental, or psychiatric disorder. Intellectual and educational abilities were evaluated twice: T1, not less than 2 years post-treatment, and T2, 3 years later. Group 1 achieved poorest results at T1, with comparison groups performing similarly. At T2 group differences were maintained. For verbal skills differences remained stable. Group 1 exhibited deterioration on non-verbal and processing tasks, while comparison groups showed improved abilities. Group 1 exhibited increases in literacy skills, with educational intervention predicting progress. Results suggest cumulative deficits in non-verbal and information processing skills for children treated with CRT + chemotherapy, with other deficits remaining relatively stable over time. Improved literacy skills suggest that gains can occur with remediation.

Neurocognitive development of children after a cerebellar tumor in infancy: A longitudinal study

PURPOSE

To assess the long-term neuropsychologic effects experienced by children who have tumors in the cerebellum that are diagnosed and treated during infancy.

PATIENTS AND METHODS

Twenty-seven children with posterior fossa tumors diagnosed at less than 36 months of age were assessed prospectively with a comprehensive set of age-appropriate tests. Group means and SDs are reported for assessments conducted at diagnosis (analysis 1) and at the most recent follow-up appointment (analysis 2). Cognitive developmental growth curves were derived from the prospective data (analysis 3) using mixed model regression analyses and controlling for age at diagnosis and socioeconomic status.

RESULTS

In the first analysis, eight of 11 infants at diagnosis scored within normal limits on all neuropsychologic domains, except for motor skills, which were impaired. In the second analysis, mean scores at the most recent follow-up of 21 of 27 patients were mostly in the normal range; however, group comparisons between those who had (n = 7) and had not (n = 14) been treated with cranial radiation therapy (CRT) showed that patients in the irradiated (CRT) group scored significantly lower than those in the nonirradiated (No-CRT) group on verbal intelligence quotient (IQ) and in the motor domain. In the third analysis (growth curves of CRT and No-CRT groups), statistically significant differences in slope were found on verbal IQ, performance IQ, perceptual-motor skills, language, and attention/executive skills. Slopes on the fine-motor domain were similar; both groups declined at approximately the same rate.

CONCLUSION

Neurocognitive development and outcome of children with cerebellar tumors diagnosed in infancy is very positive among those who were treated with surgery and chemotherapy. Declines in performance across time were minimal, and scores tended to remain within normal limits. By itself, a cerebellar tumor in infancy does not seem to have a significant impact on children. However, those who received CRT as part of their treatment are likely to have neurocognitive and psychosocial deficits that require remediational interventions.

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.

Reduced incidence of the somnolence syndrome after prophylactic cranial irradiation in children with acute lymphoblastic leukemia

A prospective double blind randomized trial comparing two different dose schedules of continuous steroid coverage during prophylactic cranial radiotherapy (CRT) in leukemic children was conducted to find out the optimum dose to be prescribed to reduce the incidence of Somnolence Syndrome (SS). Between April 1994 and February 1996, 32 patients with acute lymphoblastic leukemia received CRT of 18 Gy in 10 fractions. Patients were randomized to receive oral dexamethasone of 2 or 4 mg/m2 during radiotherapy. The diagnosis of SS was made clinically based on symptoms of somnolence. All patients were followed for a minimum of 8 months. The overall incidence of SS was 40%. The development of SS was steroid dose dependent. In low dose steroid arm the incidence of SS was 64.3% (9/14), compared to 17.6% (3/17) in high dose arm with statistically significant difference (P = 0.008). The median time to development of SS was 4 weeks. The most common symptom of SS was drowsiness followed by anorexia, headache, nausea, vomiting, decreased activity, irritability, fever and ataxia, respectively. The duration of symptoms ranged from 2 to 14 days. The development of SS was not related to the presence of acute reactions, age at the time of CRT and sex. In all cases the symptoms subsided completely and spontaneously. Our results suggest that steroid coverage at a dose of 4 mg/m2 during CRT reduces the incidence of SS. However, a multicentric prospective randomized trial is needed to determine the role and the optimal dose of steroid.

Leukoencephalopathy after CNS prophylaxis for acute lymphoblastic leukaemia

A 16 year old boy with epilepsy and learning difficulties is reported. At 3 years of age he was diagnosed with common acute lymphoblastic leukaemia, and received therapy according to the UK protocol, UKALL VIII. This included prophylactic CNS radiotherapy and chemotherapy. He did not develop CNS leukaemia, and complete remission was achieved. At age 7, he began to experience lethargy and learning difficulties, especially problems with hand-writing, concentration and memory. Furthermore, he began experiencing atypical absence seizures, which were provoked by concentration at times of tiredness. EEG showed bilateral non-specific abnormalities, with some epileptiform features. Over the following 9 years, several anti-epileptic drugs were prescribed. Although with the changes in therapy initial remissions have been achieved, the seizures have, each time, continued to relapse. At age 12, EEG was very abnormal, showing frequent generalized slow or sharp waves. At age 13, MRI revealed multiple discrete small high-intensity lesions in the subcortical white matter of both hemispheres. Problems with lethargy, concentration and memory persist and although multiple anti-epileptic drugs have been prescribed, seizures continue to occur almost daily.

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.

Cerebellar hypoplasia and frontal lobe cognitive deficits in disorders of early childhood

A developmental chronometry hypothesis of early brain damage is suggested in which regions of the brain with a protracted course of postnatal development will be more vulnerable than earlier maturing areas to deleterious effects of early insult and, therefore, may become common sites of abnormality across many disorders originating in early childhood. Initial investigations of the cerebellum and frontal lobes are presented using MRI and neuropsychological measures. Planimetric measures of the cerebellar vermis (lobuli I-V and VI-VII) and pons, and neuropsychological frontal lobe measures were obtained from high functioning individuals with autism (A), survivors of acute lymphoblastic leukemia (ALL) with brain sequelae following radiation and chemotherapy, and from rigorously selected healthy controls (C). The neuropsychological results were clustered according to functions commonly related to frontal brain, posterior brain, and left and right hemispheres. The A and ALL groups, as compared to C, yielded modest but consistently reduced MRI measures for vermal lobuli I-V and VI-VII. Hypoplasia of lobuli VI-VII was more marked than I-V. Performance on neuropsychological tests for frontal lobe functions was generally depressed in both groups, with more severe deficits in A. Between-group differences in verbal, visual-spatial, and emotional-social skills are discussed. The cerebellar and frontal brain deficits that are present in both clinical groups (A and ALL) may be common to other developmental and acquired disorders of early childhood. Such joint manifestation of cerebellar and frontal lobe abnormalities is in agreement with the concept of cerebellar significance for the development of higher cognitive functions.

Neurobehavioural sequelae following cranial irradiation and chemotherapy in children: an analysis of risk factors

Neurobehavioural deficits are commonly reported following treatment for childhood cancers. This study examined the impact of cranial irradiation (CRT) and chemotherapy in children, aiming to identify factors detrimental to long-term outcome. The study compared survivors of acute lymphoblastic leukemia (ALL), treated with CRT and chemotherapy (CRT group: n = 100), survivors of cancers treated with chemotherapy only (n = 50) and healthy controls (n = 100) for intelligence, academic achievement, information processing, learning, and executive function. CRT and chemotherapy in combination were associated with reduced intelligence, educational skill, immediate memory, processing speed, and executive function. Children treated with chemotherapy alone exhibited subtle information processing deficits. Within the CRT group, younger age at treatment was predictive of deficits in non-verbal ability, educational skills and executive functions. High dose CRT was associated with poorer information processing and lower arithmetic ability.

School functioning for the child with leukemia in continuous first remission: screening high-risk children

It is well known in the literature that cancer creates educationally related barriers for all children, which may or may not contribute to clinically relevant school problems. The goal of this study was to obtain a base rate for the characteristic pattern of school functioning for children with leukemia, so that the children with the most serious difficulties might be discovered and given the different and flexible help needed. From 1988 through 1994, a questionnaire was administered annually to teachers of all leukemic children in our center. The 291 questionnaire were used to compare the school functioning of children with leukemia with that of matched controls chosen by each teacher as representative of the class as a whole, excluding special education and developmentally disabled students. This approach to matching was chosen as a control for socioeconomic factors as well. The study was conducted with all patients with leukemia entering the center residing in the region of Lombardy, attending school, and either in therapy or out of therapy. After initial treatment, the children with leukemia in our center as a group attended school regularly and willingly. Analyses of variance (ANOVAs) were conducted on the total scores and on scores for each of the subareas of learning, socialization, and emotionality. T-tests, were given to contrast individual item scores of patients with those of their matched controls. On most individual items, children with leukemia did not differ from their classmates. However, significant discrepancies between children with leukemia and their classmates appeared consistently year after year on overall total scores and on each of the three major subcomponents of the test (learning, socialization, and emotionality). The groups most affected were children who were cranially irradiated and children who were under 6 years of age at diagnosis. Children who have been irradiated and children diagnosed under 6 years of age have the greatest risk for difficulties in school functioning and are candidates for greater attention and preventive efforts.

Brain atrophy in children undergoing systemic chemotherapy for extracranial solid tumors

It has been shown that intrathecal chemotherapy may cause brain damage, which can be depicted in neuroimaging studies. The aim of this work was to examine possible morphologic alterations in the brain of children with extracranial solid tumors, without CNS complications, treated with systemic chemotherapy. Brain CT images of 69 children with extracranial malignancies were reviewed and the extent of 12 CSF compartments was measured in 49 CT examinations performed during intravenously given chemotherapy and in 20 after therapy completion. Measurements were compared with corresponding normative data. About half of the children undergoing chemotherapy and half of the patients examined after treatment were found to have diffuse brain atrophy. Focal lesions that might be associated with therapy toxicity were not observed. Chemotherapy, even when administered via the systemic route, may cause brain damage, which is observed long after the end of treatment.

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.

Quantitative assessment of cerebral atrophy during and after treatment in children with acute lymphoblastic leukemia

RATIONALE AND OBJECTIVES

The authors evaluate quantitatively brain atrophy induced by central nervous system prophylaxis in children treated for acute lymphoblastic leukemia during and after therapy completion.

METHODS

Measurements of the width of the subarachnoid compartments were performed in 243 brain computed tomography (CT) examinations of 196 children examined during (125) and/or after (71) treatment for acute lymphoblastic leukemia without central nervous system involvement. Data were compared with normative data. RESULTS. Diffuse brain atrophy was observed in 74% and 65% of the CT examinations performed during and after cessation of treatment, respectively. The highest incidence of brain atrophy (78%) occurred during the administration of intrathecal chemotherapy. All children younger than 2 years of age exhibited brain atrophy.

CONCLUSIONS

Brain atrophy is the principal CT finding in the majority of children treated for acute lymphoblastic leukemia and it can be attributed mainly to intrathecal chemotherapy. This finding can be observed long after therapy completion.

Cytogenetic damage measured in human sperm following cancer chemotherapy

Germ-line cytogenetic damage is well documented in laboratory animals exposed to anti-cancer agents, but has been harder to verify in the human. This paper reviews published studies demonstrating cytogenetic damage in human sperm following exposure to anti-cancer chemicals, as measured by the human-sperm/ hamster-egg cytogenetic technique and fluorescence in situ hybridization. These two assays have provided important information on one step in the pathway leading to induced, transmissible germ line damage in the human. By way of introduction, a short review of the traditional human endpoints used to address the question of induced, transmissible genetic damage in human germ cells (mutation epidemiology) related to anti-cancer chemicals is presented.

Treatment of patients with high grade non-Hodgkin's lymphomas and central nervous system involvement: is radiation an essential component of therapy?

We have retrospectively examined the outcome of 41 patients with high grade non-Hodgkin's lymphomas (NHL) and central nervous system (CNS) involvement who were treated with and without radiation at a single institution. Group I consisted of 25 patients with CNS involvement at presentation and Group II, of 16 with CNS involvement at first relapse. All 41 had systemic disease at diagnosis and received systemic and intrathecal chemotherapy. Response to therapy did not differ whether patients received concomitant radiation or no CNS radiation. Thirteen of 16 non-irradiated (81%) and 8 of 9 irradiated Group I patients (89%) achieved complete responses. Three of 4 non-irradiated (75%) and 7 of 12 irradiated (58%) Group II patients achieved complete responses. CNS relapse patterns were similar whether or not patients were irradiated, and regardless of radiation dose. Most patients (18) failed systemically; there were few (6) isolated CNS relapses. Survival was not improved by the addition of radiation. Of the 15 patients who achieved long term survival, 13 remained disease-free throughout their clinical course: 7 of these 13 patients (all Group I) did not receive CNS radiation and 6 (4 Group I, 2 Group II) did. In this series, in which 44% of patients who presented with CNS disease and 13% of those who relapsed with CNS became long term disease-free survivors, there was no discernable benefit from radiation, but increased toxicity was observed.

Methotrexate does not interfere with an appetitive Pavlovian conditioning task in Sprague-Dawley rats

There has been considerable interest in developing an animal model of the neuropsychological toxicity of chemotherapeutic agents used in the treatment of patients with cancer, especially children, since these agents often cause significant, long-term neuropsychological deficits. Yanovski, Packer, Levine, Davidson, Micalizzi, D'Angio (13) recently proposed such a model based on their finding that methotrexate retarded the formation of aversive Pavlovian excitatory associations. The present experiment examined the generality of methotrexate induced cognitive impairments by testing rats in Appetitive Pavlovian Conditioning tasks and a Conditioned Taste Aversion paradigm. The results of our study revealed no impairment following methotrexate exposure on the Appetitive Pavlovian tasks or on the Taste Aversion task, relative to two control conditions. While there were a number of methodological differences between the present experiment and those conducted by Yanovski et al. (13), the present results question the robustness and generality of Yanovski's et al. (13) animal model.

Leukoencephalopathy in childhood hematopoietic neoplasm caused by moderate-dose methotrexate and prophylactic cranial radiotherapy--an MR analysis

PURPOSE

The main purpose of this study was to determine influential factors related to minor leukoencephalopathy (LEP) caused by moderate-dose methotrexate (MTX) and prophylactic cranial radiotherapy (CRT) in childhood hematopoietic malignancies. We also compared the incidence of LEP following this treatment to that reported in the literature following treatment with high-dose MTX alone.

METHODS AND MATERIALS

Thirty-eight pediatric patients of hematopoietic malignancies (37 acute lymphoblastic leukemias, 1 non-Hodgkin lymphoma) who were given CRT (18-24 Gy) as well as prophylactic intrathecal and per os MTX were studied for leukoencephalopathy by magnetic resonance (MR) imaging. All the patients were free from grave neuropsychiatric disturbances. The data were examined to elucidate the influential ones of five factors (patients' age, doses of intrathecal and per os MTX, dose of CRT, interval between treatment, and MR study) to develop LEP using multiple regression analysis. To compare the effect of moderate-dose MTX and prophylactic CRT on LEP to that of high-dose MTX alone, we conducted literature review.

RESULTS

Seven out of 38 patients (18%) developed LEP. From multiple regression analysis and partial correlation coefficients, the age and CRT dose seemed influential in the subsequent development of LEP. The incidence of LEP following treatment with moderate-dose MTX and prophylactic CRT appears to be less than that reported in the literature following treatment with intravenous high-dose MTX. However, even moderate-dose MTX in combination with CRT can result in a significant incidence of MR-detectable LEP, particularly in children 6 years of age or younger receiving 24 Gy.

CONCLUSION

Leukoencephalopathy was caused by moderate-dose MTX and prophylactic CRT in pediatric patients, probably less frequently than by high-dose MTX treatment alone. The influential factors were patient's age and CRT dose.

Neuropsychological deficits in very young bone marrow transplant recipients

Bone marrow transplantation (BMT) involves conditioning with cyclophosphamide and, for patients with malignant disease, total body irradiation (TBI). This study describes the neuropsychological development of 10 children treated for leukemia (n = 7), neuroblastoma (n = 1) or severe aplastic anemia (SAA; n = 2) at 3 years of age or younger. A moderate general developmental delay, with pronounced motor deficits and varying degrees of perceptual and cognitive problems, was observed in all children treated for malignant disease. Children treated for SAA had normal development. We conclude that BMT, including TBI, can be directly associated with long-term neuropsychological impairment in children treated at a very young age. Continued medical and psychological follow-up procedures are needed.

Total body irradiation: a neuropsychological risk factor in pediatric bone marrow transplant recipients

Bone marrow transplantation (BMT) involves conditioning with cyclophosphamide and, for leukemic patients, total body irradiation (TBI). Based on the concern that this may lead to later neuropsychologic impairment in children, a longitudinal study was conducted. Thirty pediatric bone marrow transplant recipients, treated for leukemia or severe aplastic anemia (SAA), and their sibling donors, were given a neuropsychological examination in 1986 and 1988. A third follow-up study of patients treated before 12 years of age was undertaken in 1990-91. We present longitudinal data on patients treated with BMT when 3-11 (n = 15) and 12-17 (n = 11) years old. No neuropsychological deficits were found in the older group, or among non-irradiated SAA patients. In the first follow-up, children treated with BMT, including TBI at 3-11 years of age, performed less well than donors on tasks involving perceptual and fine-motor speed. In the second follow-up, this group of patients also demonstrated a slight deficit in non-verbal problem solving. An additional relative decline in verbal reasoning was noted in the third follow-up, 5.5-10 years after treatment. Alertness to signs of developmental difficulties in children treated with BMT, including TBI, is recommended.