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

A meta-analysis of the neuropsychological effects of chemotherapy in the treatment of childhood cancer

BACKGROUND

Long-term neuropsychological deficits associated with pediatric cancers and the related treatments have been consistently reported. Whole brain cranial radiation therapy (CRT) is associated with neurocognitive impairment. As a result, physicians are reticent to use CRT in favor of systemic or intrathecal chemotherapy, which have a less clear impact on cognition.

PROCEDURE

The current meta-analysis examined post-treatment neuropsychological performance of children diagnosed with cancer and treated with chemotherapy to better understand the impact of chemotherapy upon cognition. Relevant test scores from 18 empirical studies were utilized and analyzed in comparison to normative data yielding 199 unique effect sizes across nine neurocognitive domains.

RESULTS

Children diagnosed with cancer, who received chemotherapy, demonstrated deficits in attentional capacity (g = -0.277). These deficits are noted in the context of relatively unaffected performance in other domains. When examining potential moderators, those tested more than 5 years after completion of treatment demonstrated better attentional performance than those tested within 5 years of treatment completion.

CONCLUSIONS

These deficits in attentional capacity have implications related to the academic success of these children. Given the potential for remediation strategies within this domain, neuropsychological assessment can be an integral aspect of long-term care plans of survivors of childhood cancer.

Childhood cancer survivors' school (re)entry: Australian parents' perceptions

Starting or returning to school after intense medical treatment can be academically and socially challenging for childhood cancer survivors. This study aimed to evaluate the school (re)entry experience of children who had recently completed cancer treatment. Forty-two semi-structured telephone interviews were conducted to explore parents' perceptions of their child's (re)entry to school after completing treatment (23 mothers, 19 fathers, parent mean age 39.5 years; child mean age 7.76 years). Interviews were analysed using the framework of Miles and Huberman and emergent themes were organised using QSR NVivo8. Parents closely monitored their child's school (re)entry and fostered close relationships with their child's teacher to ensure swift communication of concerns should they arise. The most commonly reported difficulty related to aspects of peer socialisation; survivors either displayed a limited understanding of social rules such as turn taking, or related more to older children or teachers relative to their peers. Additionally, parents placed a strong emphasis on their child's overall personal development, above academic achievement alone. Improved parent, clinician and teacher awareness of the importance of continued peer socialisation during the treatment period is recommended in order to limit the ongoing ramifications this may have on school (re)entry post-treatment completion.

Salvage craniospinal irradiation with an intensity modulated radiotherapy technique for patients with disseminated neuraxis disease

PURPOSE

To report the use and results of a novel intensity modulated radiotherapy (IMRT)-based technique used for salvage craniospinal irradiation (CSI) in 6 patients who developed neuraxis disease after initial high-dose conformal radiotherapy (RT) to the brain.

METHODS AND MATERIALS

After Institutional Review Board approval, all patients treated for disseminated leptomeningeal disease with salvage CSI using IMRT with conventional external beam radiotherapy were identified. The medical records and radiotherapy dosimetry were reviewed. Tolerance, morbidity, tumor control, and overall survival were evaluated.

RESULTS

Six patients who received IMRT-based salvage CSI were identified. The median age was 6.5 years (range 2- 34 years) at initial RT and 7.7 years (range, 3-35 years) at salvage CSI. Disease progression necessitating salvage CSI was noted at a median of 10 months (range, 1-26 months) from the initial RT. The original disease site remained well controlled in all 6 patients. The median dose of the initial RT treatment was 52 Gy (range, 30.6-60 Gy). Salvage CSI dose was 36 Gy in 20 fractions in all 6 patients. IMRT was used to treat the cranial contents excluding the previously treated area. Five pediatric patients received electron beams to spine and 1 adult patient received photon beams to spine. IMRT allowed a conformal and uniform dose distribution to the target tissue while excluding previously treated areas. Salvage CSI dose of 36 Gy, delivered using IMRT and 36 Gy using electrons or photons to the spine, proved effective in providing good control of the disease.

CONCLUSIONS

This technique of salvage CSI was effective in this patient cohort for leptomeningeal dissemination occurring outside of an area of focal irradiation. The technique was well tolerated and thus far has not been associated with any significant toxicity. Salvage therapy has been effective in 4 of the 6 patients thus far.

Are the psychological needs of adolescent survivors of pediatric cancer adequately identified and treated?

OBJECTIVES

To describe the psychological needs of adolescent survivors of acute lymphoblastic leukemia (ALL) or brain tumor (BT), we examined the following: (i) the occurrence of cognitive, behavioral, and emotional concerns identified during a comprehensive psychological evaluation and (ii) the frequency of referrals for psychological follow-up services to address identified concerns.

METHODS

Psychological concerns were identified on measures according to predetermined criteria for 100 adolescent survivors. Referrals for psychological follow-up services were made for concerns previously unidentified in formal assessment or not adequately addressed by current services.

RESULTS

Most survivors (82%) exhibited at least one concern across domains: behavioral (76%), cognitive (47%), and emotional (19%). Behavioral concerns emerged most often on scales associated with executive dysfunction, inattention, learning, and peer difficulties. Cranial radiation therapy was associated with cognitive concerns, χ(2) (1, N = 100) = 5.63, p < 0.05. Lower income was associated with more cognitive concerns for ALL survivors, t(47) = 3.28, p < 0.01, and more behavioral concerns for BT survivors, t(48) = 2.93, p < 0.01. Of the survivors with concerns, 38% were referred for psychological follow-up services. Lower-income ALL survivors received more referrals for follow-up, χ(2) (1, N = 41) = 8.05, p < 0.01. Referred survivors had more concerns across domains than non-referred survivors, ALL: t(39) = 2.96, p < 0.01; BT: t(39) = 3.52, p < 0.01. Trends suggest ALL survivors may be at risk for experiencing unaddressed cognitive needs.

CONCLUSIONS

Many adolescent survivors of cancer experience psychological difficulties that are not adequately managed by current services, underscoring the need for long-term surveillance. In addition to prescribing regular psychological evaluations, clinicians should closely monitor whether current support services appropriately meet survivors' needs, particularly for lower-income survivors and those treated with cranial radiation therapy.

Disruption of learning processes by chemotherapeutic agents in childhood survivors of acute lymphoblastic leukemia and preclinical models

OBJECTIVE

With the survival rate of acute lymphoblastic leukemia (ALL) surpassing 90 percent within this decade, new research is emerging in the field of late effects. A review of the research investigating the relationship of treatment regimens for ALL to specific late effect deficits, underlying mechanisms, and possible remediation is warranted to support continued studies.

METHODS

The clinical literature was briefly surveyed to describe the occurrence and topography of late effects, specifically neurocognitive deficits. Additionally, the preclinical literature was reviewed to uncover potential underlying mechanisms of these deficits. The advantages of using rodent models to answer these questions are outlined, as is an assessment of the limited number of rodent models of childhood cancer treatment.

RESULTS

The literature supports that childhood survivors of ALL exhibit academic difficulties and are more likely to be placed in a special education program. Behavioral evidence has highlighted impairments in the areas of attention, working memory, and processing speed, leading to a decrease in full scale IQ. Neurophysiological and preclinical evidence for these deficits has implicated white matter abnormalities and acquired brain damage resulting from specific chemotherapeutic agents commonly used during treatment.

CONCLUSIONS

The exact role of chemotherapeutic agents in learning deficits remains mostly unknown. Recommendations for an improved rodent model of learning deficits in childhood cancer survivors are proposed, along with suggestions for future directions in this area of research, in hopes that forthcoming treatment regimens will reduce or eliminate these types of impairments.

Adverse effects of treatment in childhood acute lymphoblastic leukemia: general overview and implications for long-term cardiac health

Survival of childhood acute lymphoblastic leukemia (ALL) is one of the greatest medical success stories of the last four decades. Unfortunately, childhood ALL survivors experience medical late effects that increase their risk of morbidity and premature death, often due to heart and vascular disease. Research has helped elucidate the mechanisms and trajectory of direct damage to the heart from treatment exposure, particularly to anthracyclines, and has also contributed knowledge on the influences of related chronic conditions, such as obesity and insulin resistance on heart health in these survivors. This article summarizes the key issues associated with early morbidity and mortality from cardiac-related disease in childhood ALL survivors and suggests directions for interventions to improve long-term outcomes.

Effects of chemotherapy on neurocognitive function in children with acute lymphoblastic leukemia: a critical review of the literature

Chemotherapy-only treatment has increasingly become the standard of treatment for childhood acute lymphoblastic leukemia (ALL). The objective of this review is to assess the present state of knowledge of the neurocognitive effects of central nervous system (CNS)-directed chemotherapy in children with ALL, and to formulate directions for future research. We performed a review of studies published since 1997, that included an ALL group treated with chemotherapy only and a control group. Twenty-one studies met our inclusion criteria. There is evidence of subtle long-term neurocognitive deficits survivors of childhood ALL after treatment with chemotherapy only. These involve mainly processes of attention and of executive functioning, while global intellectual function is relatively preserved. Young age at diagnosis and female sex emerged as risk factors.

Cognitive assessment of children with acute lymphoblastic leukemia: Preliminary findings

Aim:

The objective of this study was to assess the cognitive functions of Indian children with acute lymphoblastic leukemia (ALL), periodically after initiation of treatment since prospective longitudinal research in this area on the Indian population has not been adequately documented. Unlike many western studies that have targeted survivors of ALL, we aimed to bring out the cognitive outcome after initiation of treatment.

Materials and Methods:

The cognitive functions of 19 patients diagnosed to have ALL were assessed using standardized tests after induction chemotherapy, and periodically thereafter following the second course of treatment comprising central nervous system-directed radiotherapy, and chemotherapy using intrathecal methotrexate.

Results:

The study found a statistically significant decline in the intelligence quotient and a deficit in the cognitive function of analytical reasoning.

Conclusion:

This preliminary study supports findings of an earlier Indian study and many studies conducted in the west. Since the life expectancy of these children has increased and most of them have long-term survival, and even cure, we suggest that identifying and managing children with cognitive difficulties are important in the rehabilitation of these children.

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.

Behavioral and educational limitations after chemotherapy for childhood acute lymphoblastic leukemia or Wilms tumor

BACKGROUND

The improved prognosis of childhood cancer makes monitoring of functional outcome important. The purpose of this study was to evaluate behavioral and educational functioning in survivors of childhood acute lymphoblastic leukemia (ALL) or a Wilms tumor. In this study, children with ALL received central nervous system directed chemotherapy without cranial irradiation.

METHODS

In a multicenter study, behavioral functioning and school performance was examined in 199 children age 4 to 18. Sixty-four children were at least 1 year from finishing treatment with chemotherapy for ALL (n = 28) or a Wilms tumor (n = 36). They were compared with siblings (n = 37) and with a control group of healthy schoolchildren (n = 98).

RESULTS

A moderately increased risk of behavioral and educational problems was found in children with ALL but not in children with Wilms tumor. School performance was poorer in children with ALL attending primary school compared with same-age peers; however, the rate of utilization of special education services was low. Teacher-rated behavior and mathematics performance was correlated with attention function in children with ALL. An excess of problem behavior and underperformance at school was found in the ALL high-risk group compared with the standard-risk group. No differences were found between siblings and controls.

CONCLUSION

Evidence is provided of subtle but significant behavioral and educational problems in survivors of childhood ALL, but no dysfunctions in survivors of a Wilms tumor. Careful follow-up of children with ALL treated with chemotherapy only is warranted.

Busulfan and cyclophosphamide as a conditioning regimen for pediatric acute lymphoblastic leukemia patients undergoing bone marrow transplantation

Bone marrow transplantation (BMT) has become the standard therapy for children with relapsed acute lymphoblastic leukemia. The authors report their experience with histocompatible BMT for 52 children with acute lymphoblastic leukemia conditioned with a non-total body irradiation (TBI) regimen using busulfan and cyclophosphamide (Bu/Cy). The efficacy and long-term toxicity of the Bu/Cy regimen were determined. Overall survival was 35%. One-year, 3-year, and 7-year event-free survival rates were 54%, 33%, and 23%, respectively. Of the 52 BMT recipients, 26 relapsed. Thirteen of the relapsed patients received a second BMT and three were surviving as of this writing. The most frequent cause of death was leukemia relapse. An initial remission duration of less than 18 months was a factor in decreasing the event-free survival. The Bu/Cy regimen was well tolerated, with minimal transplant-related mortality. Neurocognitive function was tested before BMT and 1 year after BMT. When 1-year posttransplant neurocognitive test scores were compared with pretransplant scores, there was no decrease. However, there was a significant decrease in the pretransplant neurocognitive test scores in BMT recipients compared with their normal siblings. The use of Bu/Cy as a conditioning regimen for BMT does not appear to affect posttransplant neurocognitive function. Other long-term side effects, such as endocrinopathies and secondary malignancies, were also minimal. These data show that the Bu/Cy regimen is well tolerated, but the overall survival rate remains low.

CNS-directed therapy in young children with T-lineage acute lymphoblastic leukemia: High-dose methotrexate versus cranial irradiation

BACKGROUND

Prophylactic use of cranial radiation therapy (CRT) in young children with acute lymphoblastic leukemia (ALL) is associated with significant long-term morbidity. Therefore, current treatment protocols for pediatric B-precursor ALL have abandoned prophylactic CRT in favor of intrathecal chemotherapy, combined with either high-dose methotrexate infusions (HD-MTX) or intensive systemic chemotherapy. In contrast, prophylactic CRT continues to be used in children with T-lineage ALL (T-ALL), who historically have had an inferior prognosis. We conducted a retrospective cohort study to determine the effect on survival of substituting HD-MTX for CRT in young children with T-ALL, a group that faces a high risk of long-term sequelae from CRT.

PROCEDURE

Twenty-six children, diagnosed with T-ALL between the ages of 1 and 5 years, were treated on the same high-risk leukemia protocol. Central nervous system (CNS) directed therapy consisted of either CRT (1,800 cGy) or HD-MTX (three doses of 8 g/m2), depending on the treatment era in which patients were diagnosed.

RESULTS

Of the 24 patients who entered remission, 12 received CRT and 12 received HD-MTX. Five-year event-free survival (EFS) (+/-SE) was 92 +/- 8% in the HD-MTX group versus 75 +/- 13% in the CRT group (P=0.23). Five-year overall survival (OS) was 100% in the HD-MTX group versus 75 +/- 13% in the CRT group (P=0.07). There were no CNS recurrences in the HD-MTX group. One patient treated with CRT developed a brain tumor.

CONCLUSIONS

The use of HD-MTX instead of CRT as CNS-directed therapy in very young children with T-ALL does not compromise survival, while avoiding the adverse long-term effects of cranial irradiation.

Cognitive and psychosocial functioning of pediatric hematopoietic stem cell transplant patients: a prospective longitudinal study

A prospective longitudinal study of cognitive and psychosocial functioning in pediatric hematopoietic stem cell transplant (HSCT) patients was conducted on three occasions: pre-HSCT, 1 year post-HSCT, and 2 years post-HSCT. In contrast to the previous hypothesis that cognitive declines would occur as a result of HSCT treatment, it was hypothesized that (1) global cognitive functioning (IQ scores), as well as specific areas would remain stable over time; (2) pre-transplant functioning would be predictive of later functioning; and (3) age would be negatively related to cognitive functioning. Based on previous research it was further hypothesized: that (4) while declines in psychosocial functioning might be seen at 1 year, functioning would improve by 2 years. 153 children and adolescents were evaluated pre-HSCT and at 1 year, with 2 year data available for 74 children. Longitudinal analyses of Wechsler IQ data were completed on 100 children (longitudinal exact test) and 52 children (repeated measures analysis of variance. Results of cognitive assessment indicated (1) stability of IQ scores over time; and (2) that the strongest predictor was pre-HSCT cognitive functioning. Psychosocial assessment results indicated: (1) a low prevalence of behavioral and social problems; (2) stability in functioning over time; (3) pre-HSCT functioning strongly predictive of later functioning.

CNS late-effects after ALL therapy in childhood. Part III: neuropsychological performance in long-term survivors of childhood ALL: impairments of concentration, attention, and memory

PURPOSE

To date, the event free survival (EFS) after treatment of childhood acute lymphoblastic leukemia (ALL) attains 80%. The survivor group is growing steadily. Therefore, the primary purpose of our study is to define the neuropsychological function and to describe which central nervous system (CNS) functions are impaired following the German ALL-BFM and COALL protocols for CNS-negative patients.

PATIENTS AND METHODS

In a cross-sectional multicenter study 121 subjects, long-term survivors of childhood ALL in first continuous complete remission were investigated. Seven years ago, the subjects were treated as standard or medium risk patients according to ALL-BFM 81, ALL-BFM 83, or COALL 82 protocols, receiving comparable treatments. According to different CNS-prophylaxes, two subgroups were compared in the study: the non-cranially irradiated MTX-group (methotrexate-group) (n = 38) and the cranially irradiated RT-group (radiotherapy-group) (with MTX i.th.) (n = 83). Intellectual and cognitive abilities of these groups were evaluated using standardized psychometric techniques. The Kaufman factors Verbal Comprehension, Perceptual Organisation and Freedom from Distractibility were calculated. Demographical and clinical data collected at the time of the diagnosis were compared between both groups. The different prognoses for patients within both groups were taken into account using a defined risk factor. Analysis of variance was conducted to relate intellectual performance to age, gender, and CNS-treatment.

RESULTS

The RT-group exhibited a lower Full Scale IQ than the MTX-group (101.2 +/- 15.9 vs. 109.9 +/- 14.9, P = 0.031). Particularly for the Kaufman factor Freedom from Distractibility the RT-group showed the lower scores (96.9 +/- 14.1 vs. 105.5 +/- 12.6, P = 0.037). Significant interactions between gender and CNS prophylactic treatment were observed for Full Scale IQ (P = 0.008), Verbal IQ (P = 0.012), Performance IQ (P = 0.024), Verbal Comprehension (P = 0.004), and Perceptual Organisation (P = 0.032).

CONCLUSIONS

Cranial irradiation in combination with MTX therapy was associated with deficits in attention, concentration, and the ability of sequencing and processing, measured by the Kaufman factor Freedom from Distractibility. Our results support the strategy of avoiding prophylactic CNS irradiation in low risk patients.

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

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

No major cognitive impairment in young children with acute lymphoblastic leukemia using chemotherapy only: a prospective longitudinal study

PURPOSE

To study, using serial neuropsychological assessment and evaluation of school achievement, persistent neuropsychological late effects in children treated for acute lymphoblastic leukemia (ALL) at a young age with chemotherapy only.

PATIENTS AND METHODS

Twenty consecutive patients underwent three evaluations, including 12 psychometric measures beside IQ. The authors applied strict methodology and a prospective-longitudinal design that started at diagnosis and extended to a median follow-up of 7 years. This report focuses on the outcome of the last evaluation. Test results were compared with healthy controls and to patients with ALL treated on a previous chemotherapy-only protocol. School achievement was evaluated in patients and their siblings.

RESULTS

At the last evaluation, significantly lower test scores in patients compared with controls were found for only 2 of 14 cognitive measures (1 intelligence and 1 attention measure). No great differences were seen between school achievement of patients and siblings. Compared with the previous chemotherapy protocol, a better outcome was seen in the current study group on two measures (one memory and one attention measure).

CONCLUSIONS

Children surviving ALL have no major cognitive impairment after chemotherapy, including intrathecal and high-dose intravenous methotrexate. The slightly better outcome in the current group may indicate possible adverse effects of more dexamethasone treatment in the previous group.

Slight cognitive impairment and magnetic resonance imaging abnormalities but normal school levels in children treated for acute lymphoblastic leukemia with chemotherapy only

OBJECTIVES

To investigate persistent neuropsychologic late effects in children treated for acute lymphoblastic leukemia at a young age with chemotherapy only by means of serial neuropsychologic assessments (NPAs), magnetic resonance imaging (MRI) of the brain, and evaluation of school levels.

STUDY DESIGN

Consecutive patients (n = 17) had 2 extensive NPAs (12 psychometric measures) after cessation of therapy. Test results were compared with those of both healthy control subjects and 28 previously treated children who received cranial irradiation. MRI findings were related to test scores. School levels were evaluated in the patients and their healthy siblings.

RESULTS

Initial participation (n = 17) and availability of the study group after 8 years of follow-up were 100%. Significant group differences between patients who received chemotherapy and healthy control subjects were found for memory and fine-motor functioning. The 17 patients combined showed 16 deficits on various test measures. MRI abnormalities were seen in 6 children, but these did not correlate with cognitive performance. No differences in school levels were seen when the patients who received chemotherapy were compared with their siblings. The current nonirradiated patients demonstrated significantly better test results and significantly fewer learning disabilities and MRI abnormalities than did the previously irradiated group.

CONCLUSION

Treatment with chemotherapy only may be associated with some cognitive impairment. However, these children attained normal school levels.

Academic career after treatment for acute lymphoblastic leukaemia

AIM

To evaluate academic career in long term survivors of childhood acute lymphoblastic leukaemia (ALL), in comparison to their healthy siblings.

PATIENTS

Ninety four children treated for ALL with cranial irradiation 18 or 25 Gy and intrathecal methotrexate as CNS prophylaxis. Median age at evaluation was 20 years; median follow up since diagnosis was 15 years at the time of the study.

METHODS

Patients and their 134 siblings completed a questionnaire on school career. The percentage of referrals to special primary schools for learning disabled, and the final level of secondary education in patients and siblings were compared, using a six point classification. Within the patient group, the effect of possible risk factors (age at diagnosis, irradiation dose, and gender) was investigated.

RESULTS

Significantly more patients than siblings were placed in special educational programmes. A significant difference was found for level of secondary education. No effect of gender or irradiation dose was found, but younger age at diagnosis was significantly related to both referrals and school levels.

CONCLUSION

Treatment for childhood ALL with cranial irradiation and chemotherapy at a young age is clearly associated with poorer academic career.

Cerebrospinal fluid concentrations of nitrate plus nitrite during the treatment of acute lymphoblastic leukaemia in childhood

To investigate the hypothesis that acute lymphoblastic leukaemia (ALL) and its treatment disturb central nervous system nitric oxide metabolism, 11 patients were studied. Serial cerebrospinal fluid (CSF) samples were collected throughout treatment and the concentration of nitrate plus nitrite (NOx) was measured. Compared to an age-matched reference population, CSF NOx was significantly increased before treatment and rose further during the induction phase of treatment. Concentrations remained high during consolidation treatment, but fell during continuing treatment and normalised by the end of treatment. In conclusion, ALL and its treatment cause an increase in central nervous system nitric oxide production. reserved.

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.

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.

Quantitative EEG in long-term survivors of acute lymphoblastic leukemia

Conventional and quantitative aspects of electroencephalographic recordings obtained during a follow-up surveillance study in long-term survivors of acute lymphoblastic leukemia in childhood were investigated with respect to differences in central nervous system prophylaxis given during antileukemic therapy and compared with data derived from healthy controls. Central nervous system prophylaxis consisted either of cranial irradiation (18 Gray, group A, n = 8) or intermediate high-dose methotrexate (2000 mg/m2; group B, n = 5), each combined with intrathecal methotrexate. Conventional electroencephalographic analysis revealed comparable results in all three study groups. However, quantitative electroencephalography showed significantly increased absolute power scores for all frequency bands in both long-term survivor groups. Relative power estimates revealed a significant increase in delta/tau activities in both prophylaxis groups compared to healthy controls, which were countered by decreased percentage power scores in the alpha-range. Quantitative electroencephalographic comparisons between both central nervous system prophylaxis groups revealed only small differences in quantity, not quality, of the observed power disturbances with slightly higher deviations in irradiated long-term survivors than in nonirradiated ones. Topographical distributions of spectral band power were comparable between all three study groups without evidence for therapy-related topographical differences.

Correlation of medical and neurosurgical events with neuropsychological status in children at diagnosis of astrocytoma: utilization of a neurological severity score

Neuropsychological studies of children who have brain tumors have yielded diverse results with respect to identifying factors that contribute to poor intellectual outcome. The purpose of this study was to evaluate the relationship between pre- and perioperative events, tumor-related factors, and the neuropsychological status of children diagnosed with astrocytoma. Events that could potentially be detrimental to neuropsychological outcome were quantified utilizing a new "neurological severity score." The Neurological Severity Score was developed as a research tool to test our hypothesis that ultimate intellectual outcome is a result of cumulative, interactive insults on the central nervous system. This study constitutes a first step in examining the predictive value of the Neurological Severity Score by evaluating its correlation with baseline neuropsychological status. Fifty-nine children who had astrocytoma (36 supratentorial and 23 infratentorial) received complete neurological and neuropsychological evaluations within 3 months of diagnosis. Each child's neurological history and examination results were scored by an independent observer using the Neurological Severity Score. Neuroimages obtained at diagnosis and at the time of neuropsychological testing were evaluated as well. For the group as a whole, memory, attention, and motor abilities were significantly below age-appropriate norms, whereas intelligence, language, and academic skills were preserved. Patterns of deficits were identified and related to tumor site. There were no significant differences in mean neuropsychological domain scores between groups based on gender, pre-versus post-operative status, ethnicity, tumor grade, or abnormalities on magnetic resonance imaging (MRI). The Neurological Severity Score was significantly inversely correlated with visual-spatial skills, memory, attention, performance IQ, and global IQ. In conclusion, among all the medical and neurological factors present at diagnosis, the neurological severity score had the highest correlation with neuropsychological scores. This instrument has promise as a research tool in investigations of the psychological effects of cancer and its treatment on children.

Neuropsychological sequelae of the treatment of children with medulloblastoma

When a malignant tumor invades the child's cerebellum, the cost of successful treatment is often significant cognitive morbidity. A review of neuropsychological outcome revealed that survivors of childhood medulloblastoma (MB) have long-term deficits in intelligence, memory, language, attention, academic skills, psychosocial function, and a compromised quality of life. These deficits varied with chronological age at tumor diagnosis and/or adjuvant treatment, type and duration of presenting symptoms, tumor extension beyond the cerebellum, a history of adjuvant radiation treatment, and time since treatment. The effects on neuropsychological outcome of other factors, such as post-surgical hydrocephalus, were less clear. To understand the interaction between two factors predictive of outcome, age at diagnosis and time since treatment, we analyzed IQ results for a new sample of 25 surgically-treated and radiated MB survivors, and found that age at diagnosis and time since treatment made separable contributions to intellectual morbidity. PIQ appeared to measure some general effects of diffuse cerebral insult because it varied with chronological age of the child at tumor diagnosis but was relatively constant in magnitude, once established. VIQ, in contrast, was somewhat less sensitive to age at diagnosis in treated MB survivors, but declined with time since treatment. These results are important for understanding the academic attainments and continuing rehabilitation needs of childhood MB survivors, because they suggest that these children progressively fail to assimilate new verbally-based knowledge at a developmentally-appropriate rate.

Risk factors for intellectual and educational sequelae of cranial irradiation in childhood acute lymphoblastic leukaemia

Long-term cognitive and educational sequelae have been inconsistently reported in children who received cranial irradiation (CRT) to prevent central nervous system (CNS) disease in acute lymphoblastic leukaemia (ALL). This study investigates a large and representative sample of survivors of ALL and compares them with non-irradiated survivors of cancer and healthy control children to determine the effect of CRT on cognitive and educational ability. Three groups of children were studied: Group 1 (n=100) survivors of ALL treated with chemotherapy and CRT, group 2 (n=50) children with a variety of malignancies treated with chemotherapy alone, group 3(n=100) healthy children. Cognitive and educational abilities of these groups were evaluated using standardised psychometric techniques. Significant differences in cognitive and educational abilities were found between the children in group 1 (chemotherapy + CRT) and the two control groups, with the children receiving CRT performing less well in a range of tests. Greatest differences were detected for tasks dependent on language function including verbal IQ, reading and spelling. Within group 1 a younger age at treatment (less than 5 years) and a higher dose of CRT (24 Gy vs 18 Gy) were predictive of poor long-term outcome for cognitive and education ability. In contrast, children who received chemotherapy alone, with or without intrathecal methotrexate, performed similarly to healthy controls. No gender differences were detected for these measures.

Neuropsychological changes in children with cancer: the treatment of missing data in longitudinal studies

Researchers conducting longitudinal studies with children or adults are inevitably confronted with problems of attrition and missing data. Missing data in longitudinal studies is frequently handled by excluding from analyses those cases for whom data are incomplete. This approach to missing data is not optimal. On the one hand, if data are missing at random, then dropping incomplete cases ignores information collected on those cases that could be used to improve estimates of population parameters (e.g., means, variances, covariances, and growth rates) and improve the power of significance tests of statistical hypotheses. On the other hand, if data are not missing at random, then dropping incomplete cases leads to biased parameter estimates and hypothesis tests that may be internally and externally invalid. This study uses three years of follow-up data from a longitudinal investigation of neuropsychological outcomes of cancer in children to demonstrate the problems presented by missing data in repeated measures designs and some solutions. In evaluating potential biasing effects of attrition, the study extends previous research on neuropsychological outcomes in pediatric cancer by inclusion of patients whose disease had relapsed, and by comparison of surviving and nonsurviving patients. Although the data presented have specific relevance to the study of neuropsychological outcome in pediatric cancer, the problems of missing data and the solutions presented are relevant to a wide variety of diseases and conditions of interest to researchers in child and adult neuropsychology.

Single photon emission computed tomography in long-term survivors of adult brain tumours

Sixteen patients with primary brain tumours were examined on average eight years after treatment with surgery or whole brain irradiation using standard clinical assessment, CT, a neuropsychological test battery, and single photon emission CT (SPECT) with 99mTc-exametazime. Seventeen lesions were discovered on inspection of SPECT images, 11 with x-ray CT. Quantitative assessment of tracer uptake compared with 16 matched healthy volunteers was consistent with the presence of lesions. Measurement of uptake in brain regions of the hemisphere not containing the primary tumour still showed significant reductions in patients. This may be due to remote direct effects of the tumour or, more likely, to the whole brain irradiation received. Psychometric performance on most tests was significantly impaired in the patient group and was correlated with abnormalities of tracer uptake to relevant brain regions.

Intellectual, educational, and behavioural sequelae after cranial irradiation and chemotherapy

Cognitive and educational sequelae are inconsistently reported in children treated with cranial irradiation for acute lymphoblastic leukaemia. This study investigated differences in these skills after cranial irradiation, controlling the effects of chemotherapy and psychosocial factors. Three groups were evaluated: 100 children diagnosed with acute lymphoblastic leukaemia and treated with cranial irradiation and chemotherapy; 50 children diagnosed with acute lymphoblastic leukaemia or other cancers and treated with chemotherapy alone; and a healthy control group of 100 children. Children in the clinical groups stopped treatment at least two years before evaluation and had no history of relapse. Children were aged between 7 and 16 at the time of assessment. Evaluation included cognitive, educational, and behavioural measures. Analyses found that children receiving cranial irradiation and chemotherapy performed more poorly than non-irradiated groups on intellectual and educational tests, with verbal and attentional deficits most pronounced. Children receiving chemotherapy alone performed similarly to controls, suggesting such treatment is not associated with adverse neurobehavioural sequelae.

Long-term neurobehavioral outcome in pediatric brain-tumor patients: review and methodological critique

This paper provides an overview of pediatric brain tumors and reviews the literature on long-term neurobehavioral outcomes for these children. Progress in this area has been slow due to numerous methodological and practical complications. While some general conclusions can be drawn, the development of comprehensive models awaits more research into the multiplicity of biological and nonbiological events, and their interactions, potentially affecting outcome. Increased theoretical and methodological sophistication will be needed to address this complex classification of diseases. Barriers to research in this area are enumerated as are suggestions for future efforts.