Cognitive and adaptive outcome in low-grade pediatric cerebellar astrocytomas: evidence of diminished cognitive and adaptive functioning in National Collaborative Research Studies (CCG 9891/POG 9130)

A quantitative meta-analysis of neurocognitive sequelae in survivors of pediatric brain tumors

BACKGROUND

Deficits in neurocognitive functioning are an important area of late effects in survivors of pediatric brain tumors, but a quantitative analysis of the magnitude of these deficits has yet to be conducted.

PROCEDURE

The purpose of the current article is to provide a comprehensive meta-analysis of the literature on long-term neurocognitive effects found in these survivors.

RESULTS

Results indicated significant deficits in both narrow and broad indices of neurocognitive functioning, and the overall magnitude of the effects across all domains ranged from small to large in magnitude (g = -0.45 to -1.43) with a large mean overall effect size of g = -0.91.

CONCLUSIONS

These findings underscore the importance of monitoring the neurocognitive late effects in survivors of pediatric brain tumors, and the need for more consistent consideration of demographic, diagnostic, and treatment-related variables in future research to allow for examination of factors that may moderate these deficits.

Low cerebellar vermis volumes and impaired neuropsychologic performance in children treated for brain tumors and leukemia

BACKGROUND AND PURPOSE

Injury of the cerebellar vermis may occur in children with brain malignancies. Because the vermis is involved in motor and cognitive functioning, the goal of this prospective longitudinal study was to evaluate treatment-related changes in vermal volumes and neuropsychologic performance in children receiving brain radiation of the cerebellum.

MATERIALS AND METHODS

Ten patients (mean age, 11.6 years) and 10 healthy children (mean age, 12.1 years) were examined. Lobar vermal volumes and performance on neuropsychologic tests evaluating motor, visual, verbal, attention, memory, and executive functions were assessed at baseline and at 6-month follow-up visits.

RESULTS

At baseline, lower mean vermal volumes and impaired performance on visual-spatial and fine-motor tasks were detected in patients. At 6-month follow-up, further decrease in vermal volumes was detected only in patients with medulloblastoma, who received the largest radiation doses to the entire vermis. The volume decrease was not associated with reduction in neuropsychologic performance compared with baseline. At 6-month follow-up, data from all subjects revealed an association between smaller vermal volumes and slower fine-motor speed and lower visual-spatial skills.

CONCLUSIONS

Reduced brain-tissue volumes following radiation have been reported previously in pediatric patients. In this study, lower vermal volumes were detected even earlier, before radiation treatment was initiated or completed. Six months postradiation, vermal volume decreases detected in patients with medulloblastoma were not accompanied by declines in already poor neuropsychologic performance. In addition to radiation, the presence of brain malignancies and preradiation treatment may be important factors affecting cerebellar vermis tissue.

Activation of the Hedgehog pathway in pilocytic astrocytomas

Pilocytic astrocytoma is commonly viewed as a benign lesion. However, disease onset is most prevalent in the first two decades of life, and children are often left with residual or recurrent disease and significant morbidity. The Hedgehog (Hh) pathway regulates the growth of higher WHO grade gliomas, and in this study, we have evaluated the activation and operational status of this regulatory pathway in pilocytic astrocytomas. Expression levels of the Hh pathway transcriptional target PTCH were elevated in 45% of tumor specimens analyzed (ages 1–22 years) and correlated inversely with patient age. Evaluation of a tissue array revealed oligodendroglioma-like features, pilomyxoid features, infiltration, and necrosis more commonly in specimens from younger patients (below the median patient age of 10 years). Immunohistochemical staining for the Hh pathway components PTCH and GLI1 and the proliferation marker Ki67 demonstrated that patients diagnosed before the age of 10 had higher staining indices than those diagnosed after the age of 10. A significant correlation between Ki67 and PTCH and GLI1 staining indices was measured, and 86% of Ki67-positive cells also expressed PTCH. The operational status of the Hh pathway was confirmed in primary cell culture and could be modulated in a manner consistent with a ligand-dependent mechanism. Taken together, these findings suggest that Hh pathway activation is common in pediatric pilocytic astrocytomas and may be associated with younger age at diagnosis and tumor growth.

Risk factors for cognitive decline in children treated for brain tumors

The long term effects of central nervous system therapy for children with brain tumors have been the subject of research since the 1970s. Many studies have demonstrated that children treated for brain tumors with surgery and standard radiation therapy have developed intellectual decline which is progressive over at least a decade. Risk factors for this cognitive deterioration have been identified and include perioperative complications, possibly hydrocephalus, high radiation dose, large volume radiation, chemotherapy (especially methotrexate), radiation vasculopathy and young age at the time of treatment. In an effort to reduce long-term neurotoxicity, efforts have been made to develop treatment regimens that reduce the impact of these risk factors. Some of these include reduced neuraxis radiation with and without adjuvant chemotherapy, conformal radiation, chemotherapy only protocols for children with optic pathway-hypothalamic tumors and a series of baby brain tumor studies in which chemotherapy (standard and high dose) has allowed radiation to be delayed, reduced or omitted. Whether these changes in therapy will ultimately improve the quality of life of the long-term survivors is uncertain. Close follow-up of these children will be required throughout their lives.

Neuroimaging and neuropsychological follow-up study in a pediatric brain tumor patient treated with surgery and radiation

Intracranial tumors are the most common neoplasms of childhood, accounting for approximately 20% of all pediatric malignancies. Radiation therapy has led directly to significant increases in survival of children with certain types of intracranial tumors; however, given the aggressive nature of this therapy, children are at risk for exhibiting changes in brain structure, neuronal biochemistry, and neurocognitive functioning. In this case report, we present neuropsychological, magnetic resonance imaging, proton magnetic resonance spectroscopic imaging, and diffusion tensor imaging data for two adolescents (one patient with ependymal spinal cord tumor with intracranial metastases, and one healthy, typically developing control) from three time points as defined by the patient's radiation schedule (baseline before the patient's radiation therapy, 6 months following completion of the patient's radiation, and 27 months following the patient's radiation). In the patient, there were progressive decreases in gray and white matter volumes as well as early decreases in mean N-acetyl aspartate/choline (NAA/Cho) ratios and fractional anisotropy (FA) in regions with normal appearance on conventional MRI. At the last follow-up, NAA/Cho and FA tended to change in the direction to normal values in selected regions. At the same time, the patient had initial reduction in language and motor skills, followed by return to baseline, but later onset delay in visuospatial and visual perceptual skills. Results are discussed in terms of sensitivity of the four techniques to early and late effects of treatment, and avenues for future investigations.

Neurocognitive status in long-term survivors of childhood CNS malignancies: a report from the Childhood Cancer Survivor Study

To assess neurocognitive functioning in adult survivors of childhood Central Nervous System (CNS) malignancy, a large group of CNS malignancy survivors were compared to survivors of non-CNS malignancy and siblings without cancer on a self-report instrument (CCSS-NCQ) assessing four factors, Task Efficiency, Emotional Regulation, Organization and Memory. Additional multiple linear regressions were used to assess the contribution of demographic, illness, and treatment variables to reported neurocognitive functioning in CNS malignancy survivors and the relationship of reported neurocognitive functioning to socioeconomic indicators. Survivors of CNS malignancy reported significantly greater neurocognitive impairment on all CCSS-NCQ factors than non-CNS cancer survivors or siblings (p < .01). Within the CNS malignancy group, medical complications (hearing deficits, paralysis and cerebrovascular incidents) resulted in a greater likelihood of reported deficits on all CCSS-NCQ factors. Total or partial brain irradiation and ventriculoperitoneal (VP) shunt placement was associated with greater impairment on Task Efficiency and Memory. Female gender was associated with a greater likelihood of impaired scores on Task Efficiency and Emotional Regulation, while diagnosis before age 2 years resulted in less likelihood of reported impairment on the Memory factor. CNS malignancy survivors with more impaired CCSS-NCQ scores demonstrated significantly lower educational attainment (p < .01), less household income (p < .001), less full time employment (p < .001), and fewer marriages (p < .001). Survivors of childhood CNS malignancy were found to be at significant risk for neurocognitive impairment that continues to adulthood and is correlated with lower socioeconomic achievement.

Pattern recognition methods in (1)H MRS monitoring in vivo of normal appearing cerebellar tissue after treatment of posterior fossa tumors

The objective of this study was to investigate the metabolic responses of normal appearing cerebellar tissue after posterior fossa tumor treatment, and to identify characteristics of the particular treatment method. Moreover, this work examined the metabolic alterations of normal appearing tissue induced by a particular tumor state including resection, stagnation, progression, and recurrence. The studied group consisted of 29 patients treated for posterior fossa tumors. All of them were irradiated with a total dose of 54 Gy at 1.8 Gy/fraction (median values). In addition, 13 underwent chemotherapy, 25 underwent total tumor resection, 18 were tumor-free in control examinations, 5 had a stable disease, and tumor progression or recurrence was observed in 2 and 4 cases, respectively. The 69 spectra, acquired using a MRI/MRS 2T system, were analyzed using Partial Least Squares Discriminant Analysis (PLS-DA) with orthogonal signal correction (OSC) spectral filtering. A significantly elevated spectral region (0.97-1.55 ppm) was observed in patients after total resection in comparison to non-operated subjects. Patients treated with chemotherapy showed an elevated band between 1.15-1.75 and 2.7-3.0 ppm and had decreases in the remaining parts of the spectra. Increases in lactate and decreases in the remaining metabolites were characteristic for the tumor progression/recurrence group. Pattern recognition methods coupled with MRS revealed significant treatment-dependent alterations in normal appearing cerebellar tissue, as well as metabolic changes induced by tumor progression/recurrence.

Rehabilitation for survivors of pediatric brain tumors: our work has just begun

CNS tumors are the second most common childhood cancer, and survival rates for children with these tumors have increased over the last few decades. Children are often treated with a combination of neurosurgery, chemotherapy and cranial radiation. Both the tumors and these therapies can lead to cognitive challenges, decreased social participation or coping, and physical dysfunction, which can impede a child’s ability to complete daily activities and participate in his or her environment. This review describes these late effects in the framework of the International Classification of Functioning, Disability and Health, and discusses the few studies that have attempted to improve children’s functioning in their environment beyond just survival.

Pediatric low-grade gliomas

Pediatric low-grade gliomas encompass a heterogeneous set of tumors of different histologies. Cerebellar pilocytic astrocytomas occur most frequently followed by supratentorial diffuse fibrillary astrocytomas. Recent research has implicated activation of the RAS/RAF/MEK pathway in tumorigenesis of these tumors. Surgery is the mainstay of therapy. Overall survival rates for patients whose tumors are completely resected are 90% or greater, 10 years from diagnosis. Conversely, most optic pathway/hypothalamic, deep midline, and brain stem gliomas have minimal potential for resection; these tumors can be difficult to treat and deserve special attention. Combination chemotherapy is currently recommended as front-line adjuvant treatment for progressive or recurrent tumors. Second-line radiotherapy can also improve overall survival but is associated with more frequent and significant neurocognitive, endocrine, and other long-term toxicities.

Late effects of therapy for pediatric brain tumor survivors

Approximately 2 of every 3 of all pediatric patients with brain tumors will be long-term survivors. However, there is a steep cost for pediatric brain tumor survivors, and the group as a whole faces significantly more late effects than many other survivors of pediatric cancers. Most of these effects can be attributed to direct neurologic damage to the developing brain caused by the tumor and its removal, the long-term toxicity of chemotherapy, or the effects of irradiation on the central nervous system. The late effects experienced by childhood brain tumor survivors involve multiple domains. This article will review the significant late effects that occur within the medical, neurocognitive, psychosocial, and economic domains of the survivorship experience. We conclude by discussing how the late effects in different domains often coexist and can create a complex set of obstacles that pose significant challenges for a survivor of a pediatric brain tumor on a daily basis.

Radiation therapy for pediatric central nervous system tumors

Radiation therapy is an important component of treatment of many pediatric central nervous system tumors. The radiation treatment target is determined by tumor histology, extent of disease, anticipated pattern of spread, and expected pattern of failure. Children cured of their tumors live to experience the long-term sequelae of radiation treatment, including developmental, neurocognitive, neuroendocrine, and hearing late effects. The development of more conformal radiation techniques has decreased inadvertent radiation dose to normal tissues and should decrease long-term treatment sequelae that are the result of normal tissue radiation. Intensity-modulated radiation therapy improves treatment conformity and decreases high dose to nearby normal tissues; however, it delivers a larger volume of low- and intermediate-dose radiation. Proton radiation eliminates exit dose to normal tissues, thereby eliminating approximately 50% of unnecessary radiation to normal tissues. The long-term clinical benefits of proton radiation in the pediatric population are just beginning to be reported in the literature.

Medical, psychological, cognitive and educational late-effects in pediatric low-grade glioma survivors treated with surgery only

BACKGROUND

Surgical resection is often the only treatment necessary for pediatric low-grade gliomas (LGGs) and is thought to define a population with an excellent long-term prognosis. The goal of this study was to describe the multidimensional late-effects of pediatric LGG survivors treated exclusively with surgery.

METHODS

A retrospective chart review of "surgery-only" LGG survivors followed at Dana-Farber/Children's Hospital Cancer Care was undertaken. Patients had to be diagnosed with an LGG before the age of 22 years, treated with "surgery-only" and be at least 2 years from diagnosis.

RESULTS

Sixty survivors were eligible with a median age at the time of review of 16.3 years and the median time since diagnosis of 8.4 years. Tumor locations were predominantly posterior fossa (47%) or cortical (33%). Eighty-five percent of patients had at least one ongoing late-effect, and 28% had three or more. The most common late-effects consisted of motor dysfunction (43%), visual problems (32%), anxiety (19%), social difficulties (19%), seizure disorders (17%), depression (15%), poor coordination/ataxia (14%), behavioral problems (13%), and endocrinopathies (10%). Nine patients had a history of suicidal ideation; two with suicide attempts. The mean full-scale IQ was normal, however, the number of survivors scoring one standard deviation below the mean was twice the expected number. Special education services were utilized by more than half of the survivors.

CONCLUSIONS

"Surgery-only" LGG survivors may be more affected by their tumor and its resection than previously appreciated. A prospective study is needed to address this survivor population.

Phase II trial of conformal radiation therapy for pediatric low-grade glioma

PURPOSE

The use of radiotherapy in pediatric low-grade glioma (LGG) is controversial, especially for young patients. We conducted a phase II trial of conformal radiation therapy (CRT) to estimate disease control by using a 10-mm clinical target volume (CTV) margin.

MATERIALS AND METHODS

Between August 1997 and August 2006, 78 pediatric patients with LGG and a median age of 8.9 years (range, 2.2 to 19.8 years) received 54 Gy CRT by using a 10-mm CTV and by targeting with systematic magnetic resonance imaging (MRI) registration. Tumor locations were diencephalon (n = 58), cerebral hemisphere (n = 3), and cerebellum (n = 17). Sixty-seven patients had documented or presumed WHO grade 1 tumors, 25 patients had prior chemotherapy, and 13 patients had neurofibromatosis type 1.

RESULTS

During a median follow-up of 89 months, 13 patients experienced disease progression. One patient experienced marginal treatment failure, eight experienced local failures, and four experienced metastatic failure. The mean and standard error 5- and 10-year event-free (87.4% +/- 4.4% and 74.3% +/- 15.4%, respectively) and overall (98.5% +/- 1.6% and 95.9% +/- 5.8%, respectively) survival rates were determined. The mean and standard error cumulative incidences of local failure at 5 and 10 years were 8.7% +/- 3.5% and 16.4% +/- 5.4%, respectively. The mean and standard error cumulative incidence of vasculopathy was 4.79% +/- 2.73% at 6 years, and it was higher for those younger than 5 years of age (P = .0105) at the time of CRT.

CONCLUSION

This large, prospective series of irradiated children with LGG demonstrates that CRT with a 10-mm CTV does not compromise disease control. The results suggest that CRT should be delayed in young patients to reduce the risk of vasculopathy.

Treatment factors associated with outcomes in children less than 3 years of age with CNS tumours

INTRODUCTION

This study aimed to document cognitive outcomes in children treated for brain tumours with surgery and/or chemotherapy before the age of 3 years and to investigate the relationship between treatment factors and cognitive outcome.

MATERIALS AND METHODS

Participants were 31 children aged 7-14 years who had been diagnosed and treated for brain tumours under the age of 3 years. Neuropsychological assessment included tests of cognitive functioning (WASI), memory (CMS) and executive functioning (BADS-C).

RESULTS AND DISCUSSION

IQ and memory functioning scores were within the normal range but executive function was significantly below the expected level. Lower socio-economic status, younger age at treatment, having undergone more than one surgical intervention, motor problems and speech and language difficulties were found to be related to cognitive functioning. Although this group of children have good outcomes in terms of IQ and memory they have significant difficulties with executive functioning.

CONCLUSION

Further research in this area is needed to allow for development of appropriate support packages for those who are most at risk.

Pediatric low-grade gliomas and the need for new options for therapy: Why and how?

Pediatric low-grade gliomas are the most common tumors of the central nervous system in children, accounting for almost 50% of all childhood brain tumors. They are a heterogeneous group of tumors with different histologic subtypes. Most treatment studies address low-grade gliomas as a single entity, depriving us of histology-specific treatment outcomes. This is mostly due to a lack of understanding of tumor biology at the molecular level. Pediatric low-grade gliomas are not benign, and most incompletely resected tumors will progress and negatively affect quality of life. The advancements made in understanding sporadic pilocytic astrocytoma and neurofibromatosis 1-associated pilocytic astrocytoma in particular have paved the way for potential targeted therapy and biological stratification. Such progress in pilocytic astrocytoma needs to be consolidated and expanded to other histologic varieties of pediatric low-grade gliomas.

Cerebellar disorders in childhood: cognitive problems

Over the last decade, increasing evidence of cognitive functions of the cerebellum during development and learning processes could be ascertained. Posterior fossa malformations such as cerebellar hypoplasia or Joubert syndrome are known to be related to developmental problems in a marked to moderate extent. More detailed analyses reveal special deficits in attention, processing speed, visuospatial functions, and language. A study about Dandy Walker syndrome states a relationship of abnormalities in vermis lobulation with developmental problems. Further lobulation or volume abnormalities of the cerebellum and/or vermis can be detected in disorders as fragile X syndrome, Downs's syndrome, William's syndrome, and autism. Neuropsychological studies reveal a relation of dyslexia and attention deficit disorder with cerebellar functions. These functional studies are supported by structural abnormalities in neuroimaging in these disorders. Acquired cerebellar or vermis atrophy was found in groups of children with developmental problems such as prenatal alcohol exposure or extreme prematurity. Also, focal lesions during childhood or adolescence such as cerebellar tumor or stroke are related with neuropsychological abnormalities, which are most pronounced in visuospatial, language, and memory functions. In addition, cerebellar atrophy was shown to be a bad prognostic factor considering cognitive outcome in children after brain trauma and leukemia. In ataxia teleangiectasia, a neurodegenerative disorder affecting primarily the cerebellar cortex, a reduced verbal intelligence quotient and problems of judgment of duration are a hint of the importance of the cerebellum in cognition. In conclusion, the cerebellum seems to play an important role in many higher cognitive functions, especially in learning. There is a suggestion that the earlier the incorrect influence, the more pronounced the problems.

Outcome of children with low-grade cerebellar astrocytoma: long-term complications and quality of life

OBJECTS

To study the long-term outcome of surgically treated low-grade cerebellar astrocytomas in children.

MATERIALS AND METHODS

We followed 31 consecutive patients under 16 years of age who were diagnosed between 1980 and 2005 in a single institution. In 21 of 31 survivors (median follow-up time 7.9 years; range 5.6-27.4 years) who agreed to participate, tumor control, neurological and cognitive complications, and their impact on behavioral and emotional adjustment and health-related quality of life (HRQoL) were comprehensively assessed qualitatively and quantitatively.

RESULTS

Neurological sequelae were found in 43%. However, age-appropriate ability to perform daily life activities was normal in all patients. Remarkably, cognitive deficits leading to significant school problems occurred in 19% and behavioral and emotional adjustment disturbances in 27%. In comparison with healthy controls, the survivors rated their HRQoL similarly or even higher.

CONCLUSION

Childhood low-grade cerebellar astrocytomas have an excellent cure rate by tumor surgery alone. When compared with other pediatric brain tumors, the risk of neurological, cognitive, emotional, and behavioral complications is relatively small. HRQoL is similar to that of healthy controls.

Cognitive and adaptive outcome in extracerebellar low-grade brain tumors in children: a report from the Children's Oncology Group

PURPOSE

To determine whether pediatric patients treated with surgery only for low-grade tumors in the cerebral hemispheres, supratentorial midline, and exophytic brainstem evidence neurocognitive, academic, adaptive, or emotional/behavioral sequelae.

PATIENTS AND METHODS

Ninety-three patients from a natural history study of low-grade astrocytomas were tested an average of 111 days after surgery. Rates of below average (< or = 25th percentile) scores in this sample were compared with test norms, and performances were compared across anatomic sites. Finally, the relationships of pre-, peri-, and postsurgical complications to outcome were investigated.

RESULTS

For the entire sample, there was a significantly elevated rate of below average scores across intelligence quotient, achievement, and adaptive behavior, but not behavioral/emotional adjustment measures. Patients with hemispheric, midline, and brainstem tumors did not differ significantly. Patients with left hemisphere tumors generally performed worse than those with right hemisphere tumors. Finally, neurobehavioral outcome was unrelated to pre-, peri-, or postsurgery complications.

CONCLUSION

After surgery for low-grade brain tumors, a significant number of patients was found to function below average, by as much as 55% compared with 25% in the normative population. Moreover, these results suggest greater risk for patients with lesions situated in the left cerebral hemisphere. Routine neuropsychological follow-up of children after treatment for low-grade tumors is recommended.

Adverse medical events associated with childhood cerebellar astrocytomas and medulloblastomas: natural history and relation to very long-term neurobehavioral outcome

OBJECTIVES

The objectives of the study are to document the incidence of medical events in survivors of childhood posterior fossa astrocytoma or medulloblastoma in four time periods (diagnosis, perioperative, short-term survival, long-term survival), and to study whether medical events predict neurobehavioral outcome.

MATERIALS AND METHODS

Twenty-nine astrocytoma and 29 medulloblastoma survivors were studied at least 5 years post-diagnosis. The incidence of medical events in each time period was compared in each group in relation to long-term intelligence, memory, functional independence, and health-related quality of life. As expected, medical and neurobehavioral outcome were poorer in the medulloblastoma group. In the astrocytoma group, poorer long-term neurobehavioral outcome was associated with more adverse medical events in the perioperative and short-term survival periods.

CONCLUSIONS

Long-term neurobehavioral outcome is related to time-dependent medical events in astrocytoma survivors. The data confirm earlier reports of poorer outcome after medulloblastoma and add new information about clinical markers of poor neurobehavioral outcome in survivors of childhood astrocytoma.

Role of the cerebellum in the neurocognitive sequelae of treatment of tumours of the posterior fossa: an update

The lengthened survival of patients with tumours of the posterior fossa has brought awareness of the neurocognitive deficits present in this patient population. In the past, these deficits were thought to be caused by radiotherapy damaging supratentorial structures known to be responsible for cognitive processing. This notion led to the development of new treatment protocols to restrict damage to supratentorial regions by decreasing the radiation dose and the irradiated volume. However, these treatment protocols have only resulted in marginal improvements, sometimes at the expense of long-term survival. Moreover, the current published work reports that non-irradiated patients with tumours of the posterior fossa exhibit similar cognitive impairments to irradiated patients. The growth and treatment of tumours of the posterior fossa also damage infratentorial structures, including the cerebellum. Findings from anatomical, clinical, and neuroimaging studies support a role for the cerebellum in cognitive functions similar to those impaired in patients with a tumour of the posterior fossa. Despite these findings, research focused on the treatment of these patients and on decreasing their cognitive impairments either ignores that the cerebellum has been implicated in non-motor functions or argues against the possibility that damage to the cerebellum might result in cognitive sequelae. Future studies need to address the possibility that the cognitive impairments of patients with tumours of the posterior fossa might be determined by a combination of factors, including damage to the cerebellum. Recognition of the important cognitive contributions of the cerebellum might lead to improved cognitive outcome and quality of life for this patient population.

Attention mediates radiation's impact on daily living skills in children treated for brain tumors

BACKGROUND

Radiotherapy is associated with an increased survival rate in children with brain tumors, but also with cognitive decline. This study examined the time-dependent effects of radiation treatment on adaptive functioning in children with brain tumors. The potentially mediating effects of attention span (Trial 1 of the Rey Auditory Verbal Learning Test [RAVLT]) assessed within 7 years of diagnosis were explored.

PROCEDURE

Twenty-two children treated with cranial radiation for third ventricle or cerebellar tumors were included in this archival study. The mean age at diagnosis was 7.62 years (SD = 4.78) and 10.16 years (SD = 3.83) at evaluation. We examined the extent to which auditory attention span was able to mediate the relationship between time elapsed since the initiation of radiation treatment (M = 2.43 years; SD = 2.37) and adaptive functioning (Vineland Adaptive Behavior Scales [VABS]).

RESULTS

Attention span was found to mediate the relationship between time since the initiation of radiation and daily living skills. These findings were shown to be specific to attention and not a reflection of generalized neuropsychological decline, nor were they a result of increasing time since diagnosis in and of itself.

CONCLUSIONS

The results of this study suggest that time since radiation may directly decrease attention and poor attention in turn may be associated with lower adaptive functioning on tasks of daily living.

A multicenter, randomized clinical trial of a cognitive remediation program for childhood survivors of a pediatric malignancy

Survivors of childhood cancer whose malignancy and/or treatment involved the central nervous system may demonstrate a consistent pattern of neurocognitive deficits. The present study evaluated a randomized clinical trial of the Cognitive Remediation Program (CRP). Participants were 6- to 17-year-old survivors of childhood cancer (N = 161; 35% female, 18% Hispanic, 10% African American, 64% Caucasian, 8% other) who were at least 1 year off treatment and who manifested an attentional deficit. They were enrolled at 7 sites nationwide. Two thirds of the participants were randomly assigned to cognitive remediation. All participants were assessed using a battery of academic achievement/neurocognitive tests and parent/teacher measures of attention. The CRP resulted in parent report of improved attention and statistically significant increases in academic achievement. Effect sizes were modest but were comparable with those for other clinical trials of brain injury rehabilitation and for psychological interventions in general. The CRP is presented as a potentially beneficial treatment for many survivors of pediatric cancer. Long-term clinical significance remains unproven. Further work is needed to improve effect sizes and treatment compliance and to address the needs of other populations with pediatric brain injury.

Parent report of attention problems predicts later adaptive functioning in children with brain tumors

Children with brain tumors are at risk for psychological and behavioral difficulties. This study examined the ability of parent report of attention problems, withdrawal, anxiety, and depression, as well as IQ, to predict later adaptive functioning in 42 children treated for brain tumors. Age at diagnosis, SES, gender, and scores on the Neurological Predictor Scale (NPS) also were examined as predictors. Parent report of attention problems, SES, and NPS were significant predictors of later adaptive functioning across domains. This finding highlights the ability of parent report of attention problems to predict later adaptive functioning in children treated for brain tumors.

Radiotherapy for pediatric brain tumors: when and how

Radiotherapy plays a central role in the treatment of pediatric brain tumors. Historically, surgical resection alone was the mainstay of treatment for pediatric CNS malignancies. During the past 75 years, radiotherapy has been incorporated into the upfront treatment of many pediatric brain tumors either as adjuvant therapy for resected tumors, definitive treatment for unresectable malignancies or as prophylactic therapy for occult microscopic disease. Many CNS malignancies, which were once universally fatal are now curable with multimodality approaches that integrate surgery, chemotherapy and radiotherapy. Unfortunately, the long-term CNS side effects of radiotherapy remain a major obstacle for survivors of childhood tumors. In this article we will discuss these issues in detail and summarize the ongoing efforts to reduce the risks of these toxicities.

Impairment of intellectual functions after surgery and posterior fossa irradiation in children with ependymoma is related to age and neurologic complications

Background

To investigate the neuropsychological outcome of children treated with surgery and posterior fossa irradiation for localized infratentorial ependymoma.

Methods

23 patients (age 0.3 – 14 years at diagnosis) who were treated with local posterior fossa irradiation (54 Gy) underwent one (4 patients) or sequential (19 patients) neuropsychologic evaluation. The last evaluation was performed at a median of 4.5 (1 to 15.5) years after RT.

Results

Mean last full scale IQ (FSIQ), verbal IQ (VIQ) and PIQ were 89.1, 94.0, and 86.2 respectively. All patients had difficulties with reading, and individual patients showed deficits in visuospatial, memory and attentional tasks. There was no trend for deterioration of intellectual outcome over time. All 5 children with IQ scores ≤ 75 were under the age of four at diagnosis. There was a significant association between the presence of cerebellar deficits and impaired IQ (72.0 vs 95.2, p < 0,001). The absence of hydrocephalus was an indicator of better neuropsychologic outcome (mean FSIQ of 102.6 vs 83.9, p = 0.025).

Conclusion

Within the evaluated cohort, intellectual functions were moderately impaired. Markedly reduced IQ scores were only seen with early disease manifestation and treatment, and postoperative neurological deficits had a strong impact on intellectual outcome.

Verbal memory impairments in children after cerebellar tumor resection

This study was designed to investigate cerebellar lobular contributions to specific cognitive deficits observed after cerebellar tumor resection. Verbal working memory (VWM) tasks were administered to children following surgical resection of cerebellar pilocytic astrocytomas and age-matched controls. Anatomical MRI scans were used to quantify the extent of cerebellar lobular damage from each patient's resection. Patients exhibited significantly reduced digit span for auditory but not visual stimuli, relative to controls, and damage to left hemispheral lobule VIII was significantly correlated with this deficit. Patients also showed reduced effects of articulatory suppression and this was correlated with damage to the vermis and hemispheral lobule IV/V bilaterally. Phonological similarity and recency effects did not differ overall between patients and controls, but outlier patients with abnormal phonological similarity effects to either auditory or visual stimuli were found to have damage to hemispheral lobule VIII/VIIB on the left and right, respectively. We postulate that damage to left hemispheral lobule VIII may interfere with encoding of auditory stimuli into the phonological store. These data corroborate neuroimaging studies showing focal cerebellar activation during VWM paradigms, and thereby allow us to predict with greater accuracy which specific neurocognitive processes will be affected by a cerebellar tumor resection.

The cerebellum in cognitive processes: supporting studies in children

Over the last decade, increasing evidence of cognitive functions of the cerebellum during development and learning processes could be ascertained. Posterior fossa malformations such as cerebellar hypoplasia or Joubert syndrome are known to be related to developmental problems in a marked to moderate extent. More detailed analyses reveal special deficits in attention, processing speed, visuospatial functions and language. A study about Dandy Walker syndrome states a relationship of abnormalities in vermis lobulation with developmental problems. Further lobulation or volume abnormalities of the cerebellum and/or vermis can be detected in disorders as fragile X syndrome, Downs's syndrome or William's syndrome. Neuropsychological studies reveal a relation of dyslexia and attention deficit disorder with cerebellar functions. These functional studies are supported by structural abnormalities in neuroimaging in these disorders. Acquired cerebellar or vermis atrophy was found in groups of children with developmental problems such as prenatal alcohol exposure or extreme prematurity. Also focal lesions during childhood or adolescence such as cerebellar tumour or stroke are related with neuropsychological abnormalities, which are most pronounced in visuo-spatial, language and memory functions. In addition, cerebellar atrophy was shown to be a bad prognostic factor considering cognitive outcome in children after brain trauma and leukaemia. In ataxia teleangiectasia, a neurodegenerative disorder affecting primarily the cerebellar cortex, a reduced verbal IQ and problems of judgment of duration are a hint of the importance of the cerebellum in cognition. In conclusion, the cerebellum seems to play an important role in many higher cognitive functions especially in learning. There is a suggestion that the earlier the incorrect influence the more pronounced the problems.

Does cerebellar injury in premature infants contribute to the high prevalence of long-term cognitive, learning, and behavioral disability in survivors?

OBJECTIVE

Although cerebellar hemorrhagic injury is increasingly diagnosed in infants who survive premature birth, its long-term neurodevelopmental impact is poorly defined. We sought to delineate the potential role of cerebellar hemorrhagic injury in the long-term disabilities of survivors of prematurity.

DESIGN

We compared neurodevelopmental outcome in 3 groups of premature infants (N = 86; 35 isolated cerebellar hemorrhagic injury, 35 age-matched controls, 16 cerebellar hemorrhagic injury plus supratentorial parenchymal injury). Subjects underwent formal neurologic examinations and a battery of standardized developmental, functional, and behavioral evaluations (mean age: 32.1 +/- 11.1 months). Autism-screening questionnaires were completed.

RESULTS

Neurologic abnormalities were present in 66% of the isolated cerebellar hemorrhagic injury cases compared with 5% of the infants in the control group. Infants with isolated cerebellar hemorrhagic injury versus controls had significantly lower mean scores on all tested measures, including severe motor disabilities (48% vs 0%), expressive language (42% vs 0%), delayed receptive language (37% vs 0%), and cognitive deficits (40% vs 0%). Isolated cerebellar hemorrhagic injury was significantly associated with severe functional limitations in day-to-day activities. Significant differences were noted between cases of cerebellar hemorrhagic injury versus controls on autism screeners (37% vs 0%) and internalizing behavioral problems (34% vs 9%). Global developmental, functional, and social-behavioral deficits were more common and profound in preterm infants with injury to the vermis. Preterm infants with cerebellar hemorrhagic injury and supratentorial parenchymal injury were not at overall greater risk for neurodevelopmental disabilities, although neuromotor impairment was more severe.

CONCLUSIONS

Cerebellar hemorrhagic injury in preterm infants is associated with a high prevalence of long-term pervasive neurodevelopment disabilities and may play an important and underrecognized role in the cognitive, learning, and behavioral dysfunction known to affect survivors.

Habit learning dissociation in rats with lesions to the vermis and the interpositus of the cerebellum

After cerebellar tumors resection, patients show motor skill learning impairments but also cognitive deficits. However, their exact origins remain controversial. Using a rat model of cerebellar injury, we assessed the involvement of two structures often damaged during resection (vermis and interpositus nuclei) on habits development. During extended training of an instrumental task, rats develop response routines that are no longer voluntary or goal-directed but habit-based, evidenced by their insensitivity to changes in the value of the reward. Here we showed that, in contrast to sham or vermis lesioned rats, discrete lesions to interpositus nuclei prevented rats from developing habits with overtraining, without motor difficulties, nor alteration of the instrumental task acquisition. Our results suggest that the role of the cerebellum can be extended from motor skill learning to cognitive routines learning. Similar habit impairment could possibly account for some of the long-term outcome difficulties observed in cerebellar-damaged patients.

Neurocognitive effects of treatment for childhood cancer

We review research on the neuropsychological effects that central nervous system (CNS) cancer treatments have on the cognitive abilities of children and adolescents. The authors focus on the two most common malignancies of childhood: leukemias and brain tumors. The literature review is structured so as to separate out earlier studies, generally those published prior to 1995, as opposed to manuscripts that have been published within the past decade. This is an important distinction for both leukemia and brain tumors. Earlier studies were ground breaking in that they began to map out what could be expected in terms of intelligence and academic problems in survivors of pediatric malignancies. Survivorship in this population has and continues to markedly increase and this is largely due to changes in treatment protocols. Research on neurocognitive effects of disease and treatment in pediatric oncology has become increasingly sophisticated, and this literature review not only reflects this trend, but highlights the growing collaboration between neuropsychology, cognitive neuroscience, and neuro-imaging. Thus, our goal was to provide a historical foundation, lead the reader towards the progression of research methodology up to the current state of the art, and perhaps most importantly, discuss future directions. These directions are especially relevant to the concepts of remediation and treatment of cognitive problems, and this is emphasized at the conclusion of the review.

Long-term effects of treatments for childhood cancers

PURPOSE OF REVIEW

The late effects of current treatments for childhood cancer increase the risk of morbidity and mortality and diminish the quality of life in long-term survivors. We selectively review the negative late cardiac, endocrine, and neurological effects of childhood cancer and its treatments and comment on current research and recommendations for the care of long-term survivors of childhood cancer.

RECENT FINDINGS

Progressive cardiotoxicity has been established. Late cardiac effects can be mitigated with the concomitant use of dexrazoxane with anthracycline. When radiotherapy is used multiple organ systems must be monitored for known late effects dependent on the location. Proper diet, physical activity, and obesity are topics that must be addressed in survivors. Late neurocognitive effects impact intelligence quotient, behavior, and achievement. Systematic follow-up with appropriate clinical screening and testing is important in diagnosing and potentially preventing late effects of cancer therapy.

SUMMARY

The new paradigm for defining successful cancer therapy is the balance between oncologic efficacy and toxicity/late effects. The complexity of late effects necessitates a multidisciplinary approach to long-term care of these patients. The high frequency, delayed onset, and potential severity of late effects demand increased and lifelong monitoring of these individuals.

Late sequela after treatment of childhood low-grade gliomas: a retrospective analysis of 69 long-term survivors treated between 1983 and 2003

The aim of the present study was to evaluate the spectrum of late effects in a large cohort of pediatric patients with low-grade gliomas (WHO grade I and II) during an observation period of 20 years. Eighty-seven patients with low-grade gliomas grouped according to tumor location (cerebellum: n=28; cerebral hemispheres: n=21; central midline: n=15; brainstem: n=12; tectum: n=5; other locations: n=6) were evaluated for tumor- and/or treatment-related late effects by analysis of medical and computer records, and personal interviews. Seventy patients underwent neurosurgery, 29 patients received additional radiotherapy and 20 additional chemotherapy. Median follow-up of survivors is 96 months with an overall survival of 79% (cerebellum: 89%; cerebral hemispheres: 95%; central midline: 80%; brainstem: 25%; tectum: 100%; other locations: 66%). Chronic medical problems (mild ataxia to multiple severe neuroendocrine deficits) are observed in 100% of patients with brainstem/central midline tumors and in 40-50% of patients with low-grade gliomas of other locations. Endocrine deficiencies were observed in 15/17 (88%) of long-term survivors who received radiotherapy. In contrast, none of the patients who underwent surgery only had endocrine deficiencies. Seven long-term survivors (10.1%) are severely disabled with permanent need of medical help. Tumor- and treatment-related late effects are common in patients with low-grade gliomas with the most severe occurring in patients with brainstem or central midline tumors. As long-term survival is excellent in patients with low-grade gliomas except for tumors located in the brainstem, future treatment studies should focus on avoiding long-term late effects.

Neurodevelopment and chronic illness: Mechanisms of disease and treatment

Successful treatment of many childhood diseases once considered terminal has resulted in the emergence of long-term effects of the disease or consequences of treatment that were previously unrecognized. Many of these long-term effects involve the central nervous system (CNS) and are developmental in the way that they emerge over time. Because we are now able to observe the natural history of childhood diseases such as sickle cell anemia or HIV, or the consequences of treatment of disease such as leukemia, brain tumors, or kidney disease, we are also able to study a number of biological mechanisms that result in long-term neurocognitive impairment. While some of the neurodevelopmental outcomes can be directly linked to structural damage of the CNS, other systems (e.g., hematologic, immunologic, pulmonary) appear to play crucial indirect roles in the development of the CNS and neurocognitive abilities because of the way that they affect the course of brain development and activity of the brain across time. Important interactions between acute disease factors, biological mechanisms, age at the time of disease or treatment effect, and disruptions in patterns of development after successful treatment or management all provide support for a neurodevelopmental model of childhood chronic illness. Testing this model may make it possible to more accurately predict the timing and degree of severity of long-term neurodevelopmental consequences, provide guidance for improved treatment and prevention, and offer better understanding of neurodevelopmental disruptions that occur in other non-chronic illness related disabilities.