Central nervous system prophylactic treatment for childhood leukemia: neuropsychological outcome studies

Vitamin D and Bone Minerals Status in the Long-term Survivors of Childhood Acute Lymphoblastic Leukemia

Background:

Low vitamin D and diminished bone minerals with the potential for fractures are one of the nonapparent late effects of acute lymphoblastic leukemia (ALL). Chemotherapy and radiation were known as two important risk factors. We evaluated these late effects in ALL survivors who were treated with chemotherapy or chemo plus cranial radiation therapy.

Methods:

In a case–control study, 33 of ALL survivors who were treated with chemotherapy (Group A), and 33 subjects who were treated with chemoplus cranial radiation (Group B) were compared against 33 matched age, sex, and pubertal stage of their healthy siblings (Group C). Standard anthropometric data were collected as well as Tanner staging for puberty, number of fractures since treatment, serum calcium (Ca), phosphorus (P), magnesium (Mg), alkaline phosphatase, parathyroid hormone, and 25-hydroxyvitamin D (25(OH) D). The independent t-test, one-way ANOVA, Chi-square test, and Tukey's test were used to analyze the data.

Results:

The findings indicated that the mean serum levels of 25(OH) D in ALL survivors (i.e. Groups A and B) with age mean score of 11.2 years and 12.3 years, average treatment length: 3.25 years and average time after treatment completion: 4 years, was lower compared to the controls group (12.94 ± 6.69, 14.6 ± 8.1, 20.16 ± 10.83, respectively, P < 0.001) but no significant difference was observed between Group A and B in this regard (P > 0.05). Other clinical and laboratory parameters had no significant differences between the survivors and control. Vitamin D deficiency (<20 ng/ml) was observed in 27% of group A and 24% of group B and vitamin D insufficiency (20–30 ng/ml) in 72.7% and 69.6% survivors of Group A and B and 48.5% of controls group (P = 0.003).

Conclusions:

ALL treatment is associated with the increase in prevalence of vitamin D insufficiency in the childhood ALL survivors and since the low vitamin D level potentially increases the risk of low bone density, subsequent malignancies, and cardiovascular disease in the survivors, close follow-up of such patients are highly recommended to prevent the stated complications.

Comparison of intelligence quotient in children surviving leukemia who received different prophylactic central nervous system treatments

Background:

Neurocognitive deficits and decrease in intelligence quotient (IQ) is one of the complication of prophylactic central nervous system (CNS) treatment in acute lymphoblastic leukemia (ALL) patients. In this study, we compare the IQ in survivors of ALL that were treated with different prophylactic CNS treatments.

Materials and Methods:

We compared 43 long-term survivors of ALL: 21 survivors with intrathecal methotrexate (IT MTX) as CNS prophylaxis, 22 with IT MTX+1800-2400 rads cranial irradiation and 20 healthy controls. The IQ was measured using the Raven's test in these patients.

Results:

Raven's test revealed significant differences in IQ between the survivors of ALL that were treated with IT MTX, IT MTX plus cranial irradiation and control group. There was no significant difference in the IQ with respect to sex, age and irradiation dose.

Conclusion:

We can that reveal that CNS prophylaxis treatment, especially the combined treatment, is associated with IQ score decline in ALL survivors. Therefore,a baseline and an annual assessment of their educational progress are suggested.

Factors influencing neurocognitive outcomes in young patients with benign and low-grade brain tumors treated with stereotactic conformal radiotherapy

PURPOSE

To present the effect of radiotherapy doses to different volumes of normal structures on neurocognitive outcomes in young patients with benign and low-grade brain tumors treated prospectively with stereotactic conformal radiotherapy (SCRT).

METHODS AND MATERIALS

Twenty-eight patients (median age, 13 years) with residual/progressive brain tumors (10 craniopharyngioma, 8 cerebellar astrocytoma, 6 optic pathway glioma and 4 cerebral low-grade glioma) were treated with SCRT to a dose of 54 Gy in 30 fractions over 6 weeks. Prospective neuropsychological assessments were done at baseline before RT and at subsequent follow-up examinations. The change in intelligence quotient (IQ) scores was correlated with various factors, including dose-volume to normal structures.

RESULTS

Although the overall mean full-scale IQ (FSIQ) at baseline before RT remained unchanged at 2-year follow-up after SCRT, one third of patients did show a >10% decline in FSIQ as compared with baseline. Logistic regression analysis demonstrated that patients aged <15 years had a significantly higher chance of developing a >10% drop in FSIQ than older patients (53% vs. 10%, p = 0.03). Dosimetric comparison in patients showing a >10% decline vs. patients showing a <10% decline in IQ revealed that patients receiving >43.2 Gy to >13% of volume of the left temporal lobe were the ones to show a significant drop in FSIQ (p = 0.048). Radiotherapy doses to other normal structures, including supratentorial brain, right temporal lobe, and frontal lobes, did not reveal any significant correlation.

CONCLUSION

Our prospectively collected dosimetric data show younger age and radiotherapy doses to left temporal lobe to be predictors of neurocognitive decline, and may well be used as possible dose constraints for high-precision radiotherapy planning.

Scholastic Achievements of Childhood Leukemia Patients: A Nationwide, Register-Based Study

Purpose

Studies concerning the scholastic achievement of survivors of childhood leukemia have yielded controversial results. We studied the school marks of childhood leukemia survivors in a register-based study.

Patients and Methods

Three hundred seventy-one patients with a diagnosis of leukemia before the age of 16 years who were born between 1974 and 1986 and alive on their 16th birthday were identified from the Finnish Cancer Registry. Five matched controls were sought for each patient from the Population Register Center of Finland. Information on the ninth-grade school report was obtained from Statistics Finland. The overall mark average and the marks (scale 4 to 10) for mother tongue, foreign language, mathematics, and physical education were compared between the patients and controls.

Results

The ninth-grade school report was obtained by 97.6% of the patients and 98.5% of the controls. The patients whose treatment included cranial irradiation had a lower overall mark average (mean difference, −0.24; 95% CI, −0.33 to −0.15) and lower marks for all assessed school subjects compared with their controls. Of the patients treated with chemotherapy alone, only the females with leukemia diagnosed before 7 years of age had lower school marks than their controls. The biggest difference was observed in the marks for foreign language among the irradiated females diagnosed at a young age (mean difference, −1.0; 95% CI, −1.25 to −0.74).

Conclusion

Leukemia treatment that includes cranial irradiation impairs scholastic achievement. It is noteworthy that treatment of leukemia with chemotherapy alone impairs school performance only in females diagnosed before school age.

Radiation as a Nervous System Toxin

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

Educational achievement, employment and living situation in long-term young adult survivors of childhood cancer in the Netherlands

This paper investigated educational achievement, employment status, living situation, marital status and offspring in 500 Dutch long-term young adults survivors of childhood cancer (age range, 16-49 years, 47% female). The results were compared with a reference group of 1092 persons with no history of cancer (age range, 15-33 years, 55% female). The impact of demographic and medical characteristics on psychosocial adjustment was studied. All participants completed a self-report questionnaire. The results showed that, although many survivors are functioning well and leading normal lives, a subgroup of survivors were less likely to complete high-school, to attain an advanced graduate degree, to follow normal elementary or secondary school and had to be enrolled more often on learning disabled programs. The percentage of employed survivors was lower than the percentage of employed controls in the comparison group, but more survivors were student or homemaker. Survivors had lower rates of marriage and parenthood, and worried more about their fertility and the risk of their children having cancer. Survivors, especially males, lived more often with their parents. Cranial irradiation dose <or=25 Gy was an important independent prognostic factor of lower educational achievement. Survivors with a history of brain/CNS tumours had a higher risk of being single than survivors with a diagnosis of leukaemia/non-Hodgkin lymphoma. These results indicate that important aspects of life are affected in a substantial number of persons who have been diagnosed with cancer during childhood or adolescence.

Cognitive functions of young adults who survived childhood cancer

Neuropsychological tests were used to determine the cognitive functioning of adult long-term survivors treatedfor childhood cancer Disease onset before the age of 5 was related to lower test scores in intelligence tests, several memory tests, and motor function tests. The cranial irradiated survivors displayed more difficulties, especially in short-term memory tests and the Wechsler Adult Intelligence Scale Digit Symbol Test as compared to nonradiated survivors. No statistically significant differences in test scores were observed between different forms of cancer The results of this study are consistent with the notion that those memory types that demand special attention and motor speed functions are especially vulnerable to cancer and its treatment.

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.

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.

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

PURPOSE

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

METHODS AND MATERIALS

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

RESULTS

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

CONCLUSION

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

Psychiatric sequelae in seriously ill children and their families

Going through a life-threatening illness as a child or adolescent is a tremendously stressful experience for the entire family. Although the majority of survivors do go on to adjust and function well, some have ongoing problems. These problems include evidence of posttraumatic stress, learning difficulties, depression, and anxiety. Their parents appear to be even more severely affected, possibly because they had a better appreciation at the time of the true dangers posed by the illness and the treatment. Little is yet known about their siblings, although it is clear that the acute stage of illness and treatment effects the entire family. Areas needing study include the long-term sequelae on siblings of survivors, as well as a better understanding of the precipitants and mediators of the problems noted in survivors and parents. Only then can interventions and preventative measures be undertaken and tested. Also needed is a better understanding of the impact of cultural differences on precipitants, mediators, and symptoms.

Neuropsychological effects of cranial radiation: current knowledge and future directions

Radiation is an invaluable therapeutic tool in the treatment of cancer, with well-established palliative and curative efficacy. As patient survival has improved, attention has focused on long-range treatment side effects. One such adverse effect, neuropsychological impairment, is incompletely understood. Much of the extant research has been directed at childhood leukemia survivors treated with low-dose whole-brain radiation. Less is known about the effects of high-dose focal or whole-brain radiation used in the treatment of brain lesions. This article reviews the scientific literature in this area, with greatest emphasis on methodologically rigorous studies. Research design considerations are discussed. Review findings suggest that low-dose whole-brain radiation (18 to 24 Gy) in children is associated with mild delayed IQ decline, with more substantial deficits occurring in children treated at a young age. A high incidence of learning disabilities and academic failure is observed in this population and may be caused by poor attention and memory rather than low intellectual level. Children who receive higher dose radiation for treatment of brain tumors experience more pronounced cognitive decline. At higher doses, whole-brain radiation, in particular, is linked to deleterious cognitive outcomes. Remarkably little is known about cognitive outcomes in irradiated adults. Preliminary findings indicate that certain cognitive functions, including memory, may be more vulnerable to decline than others. Suggestions for future research are proposed.

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.

The impact of perioperative factors on subsequent intelligence quotient deficits in children treated for medulloblastoma/posterior fossa primitive neuroectodermal tumors

BACKGROUND

Despite success in treating children with medulloblastoma/posterior fossa primitive neuroectodermal tumor (PF PNET), some children survive with significant neurocognitive sequelae. This study was performed to understand better the significance of perioperative factors on subsequent full scale intelligence quotient (FSIQ) deterioration in these children.

METHODS

Twenty-eight children who underwent prospective and serial neurocognitive testing were studied. All children underwent surgery followed by radiotherapy with or without chemotherapy between 1983 and 1987 for medulloblastoma/PF PNET and were disease free when this study was conducted. IQ testing was performed before surgery and after the completion of radiation therapy. The clinical courses of the patients were correlated with changes in the corresponding intelligence quotients of each child. Factors correlating with neurocognitive declines were examined by chi-square or Fisher exact test analysis. Differences in mean IQs were examined by the t test. Factors found to be significant were analyzed by exact logistic regression analysis.

RESULTS

The presence of adverse factors such as neurologic deficits, meningitis, or shunt infections, or the need for repeat surgery was correlated significantly with IQ deficits after treatment. Of the subset of children with one or more of these factors, 13 of 16 (81%) sustained decreases in FSIQ; 7 of 16 (43.8%) had decreases of 20 points of more. In contrast, only 3 of 12 (25%) of the children without the factors sustained FSIQ decreases, and no child sustained a decrease of more than 13 points. The mean FSIQ change after treatment in the group with factors was -15.7 (95% confidence interval [CI]: -24.0, -8.4), and the median was -18. The mean FSIQ change in the group without factors was 4.8 (95% CI: -0.5, 10.1), and the median was 5. The difference in mean FSIQ change between the two groups was significant (P < 0.0001). On univariate analysis, both the presence of adverse factors and an age less than six years correlated with neurocognitive deficit. On regression analysis, only the presence of adverse factors was significant (odds ratio 11.53; 95% CI, 1.65-116.58; P = 0.009), whereas age was not (P = 0.27).

CONCLUSIONS

Perioperative events or complications may account for some of the neurocognitive deterioration seen in these children after treatment, especially in the very young. The occurrence of these factors is associated with a significantly greater risk of IQ deterioration. Studies of the neurocognitive effects of treatment for children with medulloblastoma/PF PNET should include an analysis of these postoperative factors.

Neuropsychological evaluation of children with intracranial tumors: impact of treatment modalities

Antineoplastic treatment has a deleterious effect on intellectual functions, which is mainly attributable to radiotherapy. With the object of determining the neuropsychological disturbances associated with brain irradiation in the child, and to try to differentiate them from the effects caused by the other types of treatment (surgical and chemotherapy) as well as from the effects of the tumor itself, a cross-sectional study was carried out in 25 survivors of medial edge intracranial tumors. In order to monitor the effect of systemic chemotherapy on the cognitive functions, and the effect of prolonged absence from school, two control groups were formed, one made up of subjects treated with chemotherapy for extracranial tumors, and the other of patients with non-malignant chronic disease. Neuropsychological functions were measured using the Spanish version of the Wechsler scale, as well as the following tests: Spreen-Benton, ITPA and TALE scales, Yuste Memory Test, Thurstone Attention Test, and the Rey Complex Figure. In addition to a progressive decline found in the full scale intelligence quotient in children irradiated for intracranial tumors, variance analysis showed that these patients deteriorate mainly in visual attention and memory, but also significantly in verbal fluency and in the Performance Intelligence Quotient and all its subtests, when compared to the control groups. Visual attention and the Wechsler Picture Arrangement and Block Designs, were the tests whose decline correlated with the total radiation administered. The article relates this specific neuropsychological injury with the total brain irradiation dose but also with the structures located in the cone-down fields of irradiation to boost regions in the middle edge intracranial content.

Stereotactic radiotherapy of irregular targets: a comparison between static conformal beams and non-coplanar arcs

Stereotactic radiotherapy using a linear accelerator is usually equated with the technique of delivery using multiple non-coplanar arcs, which achieves a spherical dose distribution. As the majority of intracranial lesions are not spherical, a range of schematized tumour shapes were planned to assess the role of static conformal beams in the treatment of irregular lesions. A sphere and 2 ellipsoids, ranging from 20 to 50 mm maximum diameter located intracranially were planned using 3, 4, and 6 non-coplanar static beams with conformal blocks and were compared with four 120 degree non-coplanar arcs. Comparison of the plans was made by the relative sparing of normal tissue outside the target volume using three-dimensional dose-volume distributions. Non-coplanar arcs spared more normal tissue at low isodoses and achieved the best high dose sparing for spherical targets. For the majority of irregular targets, 3 and 4 static beams spared more tissue at doses > or = 50% and > or = 80% than the arc technique. For all irregular volumes, maximum sparing of normal tissue to isodoses > or = 50% and > or = 80% of the treatment isodose was obtained with 6 static conformal beams. We conclude that irregularly shaped tumours suitable for stereotactic radiotherapy with a linear accelerator are better treated with conformal static non-coplanar beams rather than with the multiple arc technique.

Neuropsychological outcome of children after radiotherapy for intracranial tumours

With the aim of determining the neuropsychological disturbances associated with cranial radiotherapy in the child, a cross-sectional study was carried out on 25 survivors of medial-edge intracranial tumours. Children irradiated for intracranial tumours experienced deterioration mainly in visual attention and memory, but also in verbal fluency, full-scale IQ, and performance IQ and all its subtests, compared with control groups. This deterioration progressed with time, finally involving at least abstract thought and verbal skills. The pattern of damage by irradiation varied according to the degree of brain maturity, therefore the younger the child at irradiation, the greater the decline in IQ and visual-constructive abilities, and the earlier the deterioration of visual memory and verbal skills.

Neuropsychologic impairment in adult bone marrow transplant candidates

BACKGROUND

Long-term cognitive impairment has been reported in adult bone marrow transplant (BMT) recipients. However, the degree to which such impairment is attributable to the procedure or is a condition existing before BMT is not known.

METHODS

The presence, nature, and correlates of neuropsychologic impairment were investigated in 55 adult BMT candidates, all of whom had a malignant condition. Impairment was assessed using a screening battery of standardized neuropsychologic tests.

RESULTS

Results indicated that: (1) neuropsychologic performance was associated with specific disease and treatment risk factors, in particular a history of cranial radiation or central nervous system disease treated with intrathecal chemotherapy; (2) performance on tests reflecting memory or higher cognitive processing was more likely to be impaired; and (3) the risk of impairment increased as the number of disease and treatment risk factors for cognitive impairment in the patient increased.

CONCLUSIONS

It was concluded that neuropsychologic impairment occurs in a significant minority of adult patients before BMT. Research is necessary to determine the extent to which such impairment significantly compromises patients' abilities to: (1) make decisions regarding undergoing BMT or participating in research protocols and (2) understand and execute self-care behaviors after BMT. More broadly, greater attention should be devoted to investigating the presence of long-term neuropsychologic impairment in adult patients with cancer.

Brain tumors in children and adolescents--III. Effects of radiation and hormone status on intelligence and on working, associative and serial-order memory

The effects on intelligence and memory of two post-surgical conditions (radiation treatment, hormone deficiency and supplementation) were explored in 46 children and adolescents with tumors in a variety of brain sites. Verbal intelligence, but not non-verbal intelligence, varied positively with age at radiation treatment. Memory for word meanings was unrelated to either radiation history or to hormone status. Severe deficits in serial position memory occurred with impaired hormone function and an older age at tumor onset. Severe deficits in working memory were associated with a history of radiation and a principal tumor site that involved thalamic/epithalamic brain regions. Radiation treatment and hormone status affect later cognitive function in children and adolescents with brain tumors. Although the greater vulnerability of the verbal intelligence of the younger radiated child and the serial order memory of the child with later tumor onset and hormone disturbances remain to be explained, and although the form of the relationship between radiation and tumor site is not fully understood, the data highlight the need to consider the cognitive consequences of pediatric brain tumors according to a set of markers that include maturational rate, hormone status, radiation history, and principal site of the tumor.

Long-term neuropsychologic sequelae of childhood leukemia: comparison of two CNS prophylactic regimens

To compare the late neuropsychologic toxicities of CNS prophylaxis in childhood acute lymphoblastic leukemia (ALL), a transversal assessment was performed in two groups of ALL patients and two control groups. The ALL patients had received one of the following CNS prophylaxes: cranial irradiation, 24 Gy and i.t. MTX 10 mg/m2, 6 doses (RT group, n = 25) or i.t. Ara-C 30 mg/m2 and i.t. MTX 10 mg/m2, 10 doses (ChT group, n = 29). The two control groups were: Siblings (Sb, n = 24) and Solid Tumors (ST, n = 22). Intelligence Quotient (IQ), memory, learning, attention and frontal tasks were studied. Comparative analyses between ChT and RT showed no differences in any of the tests. When RT was compared with ST or Sb, RT showed a 10-point lower mean IQ (p greater than 0.05). The results of ChT versus ST or versus Sb were worse in the ChT group. In many tests the differences were statistically significant. Analyses of the 54 ALL patients compared with the 46 controls showed significant differences in all tests except verbal memory and verbal learning. Neuropsychological sequelae of CNS prophylaxis are discussed, and in particular, the role of cranial radiotherapy and i.t. Ara-C. We conclude that prophylactic CNS therapy may cause cognitive dysfunctions.

An animal model of prophylactic cranial irradiation: histologic effects at acute, early and delayed stages

Wistar rats (body wt. 200 g) were subjected to a fractionated course of radiation similar to that used in prophylactic brain irradiation for small cell carcinoma of the lung (2000 cGy in 5 fractions over 5 days with 60Co). Effects of this regimen were assessed by histologic examination of brain sections at 1 week, 1 month and 6 months post-irradiation. With conventional stains there were no apparent differences between control and irradiated brains at any of the post-irradiation intervals. Immunohistochemistry for neurotransmitter synthetic enzymes tyrosine hydroxylase and glutamate decarboxylase, as well as histochemistry for acetylcholinesterase, failed to uncover any changes in the irradiated animals. Immunohistochemistry for glial fibrillary acidic protein, an astrocyte marker, also showed no differences in the irradiated groups. However, an antibody against a major histocompatibility complex, class II antigen (OX-6) revealed a microglial response in grey and white matter beginning at 1 month and increasing up to the 6 month post-irradiation interval. The neuroanatomical basis for this microglial response was suggested by the results of silver stains for nerve axons, which revealed axonal loss in striatal white matter bundles in a pattern implicating vascular insufficiency.

Decline in head growth and cognitive impairment in survivors of acute lymphoblastic leukaemia

Twenty five children in remission, who were asymptomatic and who had last been treated at least two years before for acute lymphoblastic leukaemia, were examined neurologically and neuropsychologically. Their treatment included early cranial irradiation (24 Gy or 18 Gy), intrathecal methotrexate, and systemic chemotherapy. One half of the children demonstrated a decline in head circumference centile, which occurred in all patients treated with 24 Gy and in those patients treated with 18 Gy under the age of 3 years. In those children whose head growth was reduced, performance was significantly impaired in neuropsychological tests designed to assess concentration and short term memory. These children also developed clinically important learning difficulties in the classroom. Minor neurological dysfunction was present in almost half of the entire group. These data suggest that the treatment employed to prevent central nervous system leukaemia (primarily cranial irradiation) has a deleterious effect on head and brain growth and intellectual function.

The effect of prenatal radiation exposure on the developing human brain

Recently reported dose responses in prenatally exposed Japanese bomb survivors for severe mental retardation (SMR), reduced intelligence, and reduced levels of school performance, are compared. The characteristics of, and differences between, severe and mild mental retardation in man are critically important for such comparisons. The meaning of linearity of dose response is not identical for these different forms of damage. When findings on tissue changes in the brain and in functional tests of irradiated experimental animals are taken into account, the dose response for SMR would be expected to have a threshold as is found using DS86 dosimetry. The dose responses for IQ and for school performance seem doubtfully valid: their underlying assumptions need re-examination.

Neurotoxicity in lymphoblastic leukaemia: comparison of oral and intramuscular methotrexate and two doses of radiation

Serial cranial computed tomograms were carried out in 136 children with acute lymphoblastic leukaemia who were receiving 24 Gy or 18 Gy of cranial irradiation and continuing treatment with doses of methotrexate given weekly orally or intramuscularly. The findings were correlated with treatment variables, the development of fits, and the intelligence quotient (IQ). Reversible brain shrinkage, attributed to treatment with steroids, was found on 87 of 114 initial scans (76%); 14 showed changes in white matter during treatment (10%), and calcification was found in 13 either during or after treatment (10%). Eight children (6%) had fits, and in six of the eight there were changes in white matter or calcification on the scans. Comparison of the two radiotherapy dosages showed no difference in the incidence of abnormalities seen on computed tomography, fits, or serial IQ measurements, but children receiving intramuscular methotrexate had a higher incidence of calcification and a lower mean IQ at one year than those who received the drug orally, although this difference was not apparent later. Younger children were more likely to develop changes on computed tomograms and fits, and to have low IQs on completion of treatment, with changes most apparent in those less than 2 years of age. There were highly significant correlations between abnormalities on computed tomography, fits, and IQ. These findings confirm the neurological vulnerability of younger children with acute lymphoblastic leukaemia, show an association between abnormalities on computed tomography and intellectual deficit, and suggest that methotrexate is more toxic when given intramuscularly than orally. They provide no evidence that 18 Gy of cranial irradiation is less toxic than 24 Gy, and indicate the need for alternative treatment regimens.

Late effects of central nervous system treatment of acute lymphoblastic leukemia in childhood are sex-dependent

The authors measured the cognitive function and physical growth of 51 children who had been treated for acute lymphoblastic leukemia with chemotherapy, cranial irradiation and intrathecal methotrexate, and who had remained disease-free for five to 12 years. A comparison group of 15 children treated for Wilms' tumor was also studied. Cognitive impairment and growth retardation were greater among the leukemia group. Of potentially greater significance, however, was the finding that female sex was the pre-eminent risk factor for central nervous system toxicity resulting from treatment. Cognitive impairment, short stature and excessive weight were all more prevalent among females than males. Approximately half the children were microcephalic, but there was no sex difference. Age at evaluation and diagnosis, as well as socio-economic status, were differentially related to outcomes for the two sexes. The authors believe the sex differences were indicative of a fundamental interaction between postnatal neural development and other biological processes.

Oncology

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Neuropsychologic and CT examinations in leukemic patients surviving 10 or more years

Long-term survivors of childhood leukemia were studied to determine their neuropsychologic status. All had had cranial irradiation 10 or more years before. The results were 1. The IQ and academic performance of 56 cured leukemic patients show no significant difference from the normal population. 2. More exact neuropsychological tests (attention, reaction time, visual-motor coordination, memory) reveal important deficits. 3. The frequency of CT aberrations in 33 study patients was 45% and showed no correlation with either the IQ or other neuropsychological results.

Central nervous system relapses after bone marrow transplantation for acute lymphoblastic leukemia in remission

This study defines the risk of central nervous system (CNS) relapse in patients undergoing bone marrow transplantation (BMT) for acute lymphoblastic leukemia (ALL) in remission, with no posttransplant prophylactic CNS therapy. Ninety-two consecutive patients in complete remission received BMT for ALL (n = 82) or high-grade non-Hodgkin's lymphoma with poor prognostic factors at diagnosis (n = 10). Sixty-six patients received allogeneic BMT (Allo-BMT) and 26 patients, without an identical sibling, underwent autologous BMT (Auto-BMT). Fifteen patients had CNS involvement at diagnosis and underwent BMT in first remission. Eight patients experienced CNS relapse after BMT, corresponding to a probability of 11% at 3 years. Apart from a history of prior CNS involvement, no patient characteristic evaluated statistically influenced CNS relapse after BMT. The probability of CNS relapse was 5.5% for the 70 patients without history of CNS involvement and 27.5% for the 22 patients with prior CNS involvement. However, subgroup analysis showed that the increased risk of CNS relapse is mainly observed in Auto-BMT patients with history of prior CNS involvement, particularly in patients undergoing BMT in first remission (three of five Auto-BMT versus one of ten Allo-BMT). Taking into account the multiple factors which influence the occurrence and the treatment of CNS leukemia, the results on this retrospective study suggests that (1) for patients without CNS involvement at diagnosis and for whom BMT is performed in first remission, cranial irradiation before BMT and posttransplant prophylactic CNS therapy can be omitted because of the low probability of CNS relapse after BMT (3.4%), when total-body irradiation (TBI) is included in the conditioning regimen; and (2) the difference observed between Allo-BMT and Auto-BMT patients with previous CNS involvement and undergoing BMT in first remission could indicate that graft-versus-host leukemia acts even in the CNS in Allo-BMT patients.

Brain damage after treatment for acute lymphoblastic leukemia. A report on 34 patients with special regard to MRI findings

In 34 patients treated for acute lymphoblastic leukemia (ALL), central nervous system (CNS) damage was assessed by clinical evaluation and brain magnetic resonance imaging (MRI). Twenty-seven of them had been off therapy from 5 to 109 months (median 64 months) while 7 had not completed the maintenance phase of their treatment. All the patients were disease-free when evaluated. None of the 3 patients who showed clinical CNS damage during the follow-up was symptomatic when submitted to MRI, while periventricular hyperintensity in T2-weighted images, suggestive of leukoencephalopathy, was present in 8 of the 34 patients. These subclinical abnormalities appear to be more frequent, transient in nature and treatment-related in patients evaluated shortly after the induction phase. Similar MRI findings seem, on the contrary, to be consequences of the disease on the CNS when appearing in long-term survivors.

Cognitive function in long survivors of childhood acute lymphoblastic leukemia

Thirty long survivors of childhood acute lymphoblastic leukemia were compared with their healthy siblings on cognitive and neuropsychological measures. The subjects were comparable in treatment variables except for type of central nervous system prophylaxis received. Thirteen were given radiotherapy with intrathecal medication, and seventeen received only intrathecal treatment. Patients receiving only intrathecal medication did not differ from controls. Patients receiving radiotherapy scored lower on several measures including Wechsler Full Scale and Performance IQ. Irradiated girls scored lower than boys on most measures. Children whose clinical management has included radiation therapy appear to be at risk for later mild cognitive deficits. No consistent pattern of neuropsychological deficits has emerged and observed deficit patterns may reflect individual vulnerabilities.

Cognitive effects of cranial irradiation in leukaemia: a survey and meta-analysis

Central nervous system (CNS) prophylaxis involving cranial irradiation has frequently been found to result in cognitive deficits in survivors of childhood acute lymphoblastic leukaemia. The existence of this effect is still controversial, however, as is the question of factors that might affect its severity. The literature is surveyed and a meta-analysis undertaken on 30 IQ comparisons, which shows a substantial average decrement in irradiated subjects. The effect is larger when radiation is administered at a younger age and appears to be progressive. The effect may comprise two elements, one common to young cancer patients and one specific to CNS prophylaxis.

Late effects of antileukemic treatment

Increasing numbers of childhood ALL survivors have increased the need to assess the physical and psychosocial functioning of this group in a careful manner. This article reviews data on the frequency and types of second malignancies, structural and functional changes in the central nervous system, endocrine effects on growth and reproduction, and psychosocial aspects of development. Most long-term survivors of ALL do not have serious or life-threatening medical problems; however, medical and psychosocial problems may not be insignificant and may require coordinated management over prolonged periods.

Long-term sequelae of cancer treatment on the central nervous system in childhood

Increasing numbers of children with cancer, including those with acute lymphocytic leukemia and medulloblastoma, are experiencing long-term disease control. As survival increases, so does the recognition that the treatment used to prolong survival may have significant detrimental effects on the central nervous system (CNS). Because of the slow replication rate of most constituents of the CNS, these effects tend to be delayed. Radiotherapy, and to a lesser extent, chemotherapy (primarily methotrexate) have been implicated in the causation of such sequelae. The pathogenesis of CNS damage is only partially understood and evidence suggests that direct effects on intracranial endothelial cells and brain white matter and immunologic mechanism play a role. A spectrum of clinical syndromes may occur, including radionecrosis, necrotizing leukoencephalopathy, mineralizing microangiopathy with dystrophic calcification, cerebellar sclerosis and spinal cord dysfunction. The two most common forms of sequelae are neuropsychological and neuroendocrinologic damage. The frequency, degree of and etiology of neurocognitive dysfunction is less than completely elucidated. Radiotherapy has been implicated as the major cause of damage, but the relationship between radiotherapy and the type of damage caused and the volume and dose of radiotherapy and degree of cognitive damage is unclear. Cognitive deficits are progressive in nature. Younger children are more likely to suffer the severest damage; but no patient of any age is free of risk of damage. Growth hormone impairment is the most common form of neuroendocrinologic dysfunction. There is increasing evidence that children with cancer who are long-term survivors are at increased risk for the development of secondary CNS tumors; possibly due, in part, to previous treatment. Much work needs to be done to characterize the sequelae which may occur, develop means of earlier detection, investigate ways to ameliorate sequelae and devise less toxic treatment.