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

Radiation-Induced Brain Injury: Age Dependency of Neurocognitive Dysfunction Following Radiotherapy

Cranial radiotherapy is a known risk factor for neurocognitive impairment in cancer survivors. Although radiation-induced cognitive dysfunction is observed in patients of all ages, children seem to be more vulnerable than adults to suffering age-related deficits in neurocognitive skills. So far, the underlying mechanisms by which IR negatively influences brain functions as well as the reasons for the profound age dependency are still insufficiently known. We performed a comprehensive Pubmed-based literature search to identify original research articles that reported on age dependency of neurocognitive dysfunction following cranial IR exposure. Numerous clinical trials in childhood cancer survivors indicate that the severity of radiation-induced cognitive dysfunction is clearly dependent on age at IR exposure. These clinical findings were related to the current state of experimental research providing important insights into the age dependency of radiation-induced brain injury and the development of neurocognitive impairment. Research in pre-clinical rodent models demonstrates age-dependent effects of IR exposure on hippocampal neurogenesis, radiation-induced neurovascular damage and neuroinflammation.

Mercaptopurine/Methotrexate maintenance therapy of childhood acute lymphoblastic leukemia: clinical facts and fiction

The antileukemic mechanisms of 6-mercaptopurine (6MP) and methotrexate (MTX) maintenance therapy are poorly understood, but the benefits of several years of myelosuppressive maintenance therapy for acute lymphoblastic leukemia are well proven. Currently, there is no international consensus on drug dosing. Because of significant interindividual and intraindividual variations in drug disposition and pharmacodynamics, vigorous dose adjustments are needed to obtain a target degree of myelosuppression. As the normal white blood cell counts vary by patients' ages and ethnicity, and also within age groups, identical white blood cell levels for 2 patients may not reflect the same treatment intensity. Measurements of intracellular levels of cytotoxic metabolites of 6MP and MTX can identify nonadherent patients, but therapeutic target levels remains to be established. A rise in serum aminotransferase levels during maintenance therapy is common and often related to high levels of methylated 6MP metabolites. However, except for episodes of hypoglycemia, serious liver dysfunction is rare, the risk of permanent liver damage is low, and aminotransferase levels usually normalize within a few weeks after discontinuation of therapy. 6MP and MTX dose increments should lead to either leukopenia or a rise in aminotransferases, and if neither is experienced, poor treatment adherence should be considered. The many genetic polymorphisms that determine 6MP and MTX disposition, efficacy, and toxicity have precluded implementation of pharmacogenomics into treatment, the sole exception being dramatic 6MP dose reductions in patients who are homozygous deficient for thiopurine methyltransferase, the enzyme that methylates 6MP and several of its metabolites. In conclusion, maintenance therapy is as important as the more intensive and toxic earlier treatment phases, and often more challenging. Ongoing research address the applicability of drug metabolite measurements for dose adjustments, extensive host genome profiling to understand diversity in treatment efficacy and toxicity, and alternative thiopurine dosing regimens to improve therapy for the individual patient.

Medication neurotoxicity in children

Medication neurotoxicity may have a variety of imaging manifestations in children. In this pictorial essay, we review the two most common brain injury patterns, posterior reversible encephalopathy syndrome (PRES) and acute toxic leukoencephalopathy (ATL). Proposed etiologies, salient features on neurological imaging, and methods for differentiating these entities and their implications will be discussed. Certain agents do not fall into these two broad patterns but instead characteristically involve central structures. We individually review several medications and their respective neurotoxic appearances including methotrexate, cyclosporine A, tacrolimus, metronidazole and vigabatrin. Diagnosis of medication neurotoxicity may be achieved by the combination of new-onset neurological deficits, recent initiation of a new therapy agent and distinctive findings on magnetic resonance imaging. Clinical and radiological improvement and/or resolution are frequently observed after the agent is discontinued.

Late-occurring neurologic sequelae in adult survivors of childhood acute lymphoblastic leukemia: a report from the Childhood Cancer Survivor Study

PURPOSE

Children with acute lymphoblastic leukemia (ALL) are often cured, but the therapies they receive may be neurotoxic. Little is known about the incidence and severity of late-occurring neurologic sequelae in ALL survivors. Data were analyzed to determine the incidence of adverse long-term neurologic outcomes and treatment-related risk factors.

PATIENTS AND METHODS

We analyzed adverse neurologic outcomes that occurred after diagnosis in 4,151 adult survivors of childhood ALL who participated in the Childhood Cancer Survivor Study (CCSS), a retrospective cohort of 5-year survivors of childhood cancer diagnosed between 1970 and 1986. A randomly selected cohort of the survivors' siblings served as a comparison group. Self-reported auditory-vestibular-visual sensory deficits, focal neurologic dysfunction, seizures, and serious headaches were assessed.

RESULTS

The median age at outcome assessment was 20.2 years for survivors. The median follow-up time to death or last survey since ALL diagnosis was 14.1 years. Of the survivors, 64.5% received cranial radiation and 94% received intrathecal chemotherapy. Compared with the sibling cohort, survivors were at elevated risk for late-onset auditory-vestibular-visual sensory deficits (rate ratio [RR], 1.8; 95% CI, 1.5 to 2.2), coordination problems (RR, 4.1; 95% CI, 3.1 to 5.3), motor problems (RR, 5.0; 95% CI, 3.8 to 6.7), seizures (RR, 4.6; 95% CI, 3.4 to 6.2), and headaches (RR, 1.6; 95% CI, 1.4 to 1.7). In multivariable analysis, relapse was the most influential factor that increased risk of late neurologic complications.

CONCLUSION

Children treated with regimens that include cranial radiation for ALL and those who suffer a relapse are at increased risk for late-onset neurologic sequelae.

Intrathecal methotrexate-induced acute chorea

Intrathecal methotrexate is the mainstay of central nervous system prophylaxis in acute lymphoblastic leukemia. We describe a patient who developed acute chorea after last dose of intrathecal methotrexate therapy and recovered completely.

Antimetabolite therapy for lesser-risk B-lineage acute lymphoblastic leukemia of childhood: a report from Children's Oncology Group Study P9201

Pediatric Oncology Group (POG) protocol 9201 enrolled children with lesser-risk B-lineage acute lymphoblastic leukemia (ALL) defined by age (1-9), white blood cell count (WBC) less than 50 x 10(9)/L (50,000/microL), DNA findings of trisomies 4 and 10 (or DNA index > 1.16), and lack of overt central nervous system (CNS) leukemia. After vincristine, prednisone, and asparaginase induction, 650 of 653 eligible patients attained remission (3 induction deaths) and received 6 courses of intravenous methotrexate (1 g/m(2)) with daily mercaptopurine. Weekly intramuscular methotrexate was added during maintenance; pulses of vincristine and prednisone were administered with periodic intrathecal chemotherapy. Treatment duration was 2.5 years. No alkylators, epipodophylotoxins, anthracyclines, or radiation were given. The 6-year event-free survival (EFS) was 86.6% with overall survival (OS) of 97.2%. Patients with less than 5% marrow blasts on induction day 15 had superior EFS. A difference not reaching conventional statistical significance (P = .068) was noted for superior outcomes in patients with trisomies of chromosomes 4 and 10 versus those lacking double trisomies. Sex, ethnicity, CNS status, and WBC were not predictive. This indicates the great majority of children with lesser-risk B-lineage ALL are curable without agents with substantial late effects.

Diffusion-weighted MR imaging of early methotrexate-related neurotoxicity in children

BACKGROUND AND PURPOSE

Methotrexate is a major cause of treatment-related acute neurotoxicity in children with hematologic malignancies. The purpose of this study was to investigate whether diffusion-weighted MR imaging (DWI) detects acute methotrexate white matter neurotoxicity in this patient population.

METHODS

Six children-three female and three male-with hematologic malignancies were studied at time of onset of neurologic dysfunction during the delayed intensification or consolidation phase of therapy, when intensive intrathecal methotrexate is given. MR imaging including DWI was performed on 1.5 T MR scanners.

RESULTS

DWI demonstrated abnormal restriction of motion of water in the centrum semiovale in all six patients. This finding correlated to the acute onset of hemiparesis or aphasia. Fluid-attenuated inversion recovery imaging was not positive at this time, but it was positive in all five patients in whom follow-up imaging was performed.

CONCLUSION

Early detection of methotrexate white matter injury by DWI has the potential to alert the oncologist to this event and provide a technique by which treatment of neurotoxicity can be monitored.

Visual attention in long-term survivors of leukemia receiving cranial radiation therapy

The effect of cranial radiation therapy (CRT) on visual attention was examined in long-term survivors of childhood acute lymphoblastic leukemia (ALL) compared to peers with no history of ALL (n = 24) using a cued orienting task and a global-local task. ALL participants treated with CRT (n = 13) demonstrated an increased cost in response time with invalid spatial orienting cues and inefficient shifts of attention across hierarchical levels. ALL participants treated only with chemotherapy (n = 8) showed performance similar to the non-ALL comparison group. Participants with exposure to CRT early in life appeared to largely account for the attention deficits, and showed particular difficulties with shifting attention from the local level of stimuli to the global level. The data are consistent with prior reports emphasizing attention deficits following CRT, and suggest that attention shifting may be particularly affected by CRT early in life.

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.

Acute neurotoxicity in children with B-lineage acute lymphoblastic leukemia (B-ALL) treated with intermediate risk protocols

BACKGROUND

This study describes the incidence of acute neurotoxicity (NT) in children with B-lineage acute lymphoblastic leukemia (ALL) treated with three intermediate risk protocols that differ in the intensity of central nervous system (CNS) "prophylaxis. "

PROCEDURE

A total of 122 patients (64 boys; median age 5.3 years) with B-lineage ALL without CNS leukemia diagnosed between February 1987 and December 1997 were enrolled in the intermediate risk (IR) protocols: Associazione Italiana di Ematologia ed Oncologia Pediatrica (AIEOP)-ALL 87 (n = 33), 91 (n = 51), and 95 (n = 38). Presymptomatic CNS therapy consisted of intrathecal methotrexate (six doses) and cranial irradiation (18 Gy) in the IR AIEOP 87 study, and extended triple intrathecal therapy with methotrexate, cytarabine, and prednisone depending on age in the IR AIEOP-ALL 91 and 95 protocols (20 and 17 total doses, respectively). World Health Organization (WHO) grade 4 acute neurotoxicity criteria were employed. Patients with neurologic symptoms, in addition to physical examination, underwent EEG, computed tomography (CT) and/or magnetic resonance imaging (MRI), and lumbar puncture to exclude CNS leukemia and infection.

RESULTS

Acute NT was not reported in AIEOP-ALL 87 treated patients, but we observed acute NT in 3 out of 51 (5.8%) AIEOP-ALL 91 patients, and in 7 out of 38 (18.4%) AIEOP-ALL 95 patients.

CONCLUSIONS

There was an increased incidence of acute NT in our patients with ALL treated with current intermediate risk protocols. The intensification of treatment, however, bettered event free survival (EFS) to 58%, 72% and 85% in IR AIEOP 87, 91 and 95 studies, respectively.

Magnetic resonance spectroscopy in the evaluation of neurotoxicity following cranial irradiation for childhood cancer

In order to evaluate the role of proton MR spectroscopy (1H-MRS) in the diagnosis and assessment of long-term radiation-related neurotoxicity, 14 children who had received cranial irradiation for the treatment of childhood leukaemia (n = 6) or brain tumours (n = 8) underwent 1H-MRS, MRI and neuropsychological assessment. Short-term effects at 2 months following treatment were studied in a further three patients. MRI abnormalities were observed in nine patients. No statistically significant differences between patients and controls (n = 17) were seen in any of the calculated 1H-MRS metabolite ratios, in any of the three patient groups. On multivariate logistic regression analysis there was a correlation between the choline/water ratio and a low IQ. It is concluded that any systematic radiation-induced changes in the 1H MRS metabolites must be below the detection threshold of this study.

Incidence of TEL/AML1 Fusion Gene Analyzed Consecutively in Children With Acute Lymphoblastic Leukemia in Relapse

The translocation t(12; 21)(p13; q22) is difficult to detect by classic cytogenetics. However, using fluorescence in situ hybridization (FISH) and by screening for the TEL/AML1 rearrangement by the polymerase chain reaction (PCR), it has been demonstrated to be the most frequent known structural chromosomal abnormality in childhood acute lymphoblastic leukemia (ALL). It is closely correlated with a B-cell precursor (BCP) phenotype and is considered a favorable prognostic factor. However, little is known about the incidence of the translocation in relapsed patients and the duration of complete remission (CR) in children expressing the TEL/AML1 fusion gene. We therefore examined 49 bone marrow samples from children with ALL at first or second relapse that were consecutively mailed to our laboratory to test for the presence of t(12; 21) using reverse transcriptase (RT)-PCR. The TEL/AML1 rearrangement could be identified in nine of 44 (20%) of the patients, a result similar to the reported incidence at diagnosis. Most of the TEL/AML1–positive children showed no adverse clinical features at diagnosis (eg, white blood cell [WBC] count <100 × 109/L or age <10 years), and regarding these data, there were no differences versus children who were negative for the fusion gene. However, the period of remission was about 1 year longer in children expressing TEL/AML1 (P = .046), and the majority of relapses in this group appeared late (<2 years after diagnosis). Our findings therefore reinforce the urgent need for further prospective studies with a long follow-up period to determine the true prognostic significance of t(12; 21) and to avoid premature changes of treatment strategies.

Incidence of TEL/AML1 Fusion Gene Analyzed Consecutively in Children With Acute Lymphoblastic Leukemia in Relapse

The translocation t(12; 21)(p13; q22) is difficult to detect by classic cytogenetics. However, using fluorescence in situ hybridization (FISH) and by screening for the TEL/AML1 rearrangement by the polymerase chain reaction (PCR), it has been demonstrated to be the most frequent known structural chromosomal abnormality in childhood acute lymphoblastic leukemia (ALL). It is closely correlated with a B-cell precursor (BCP) phenotype and is considered a favorable prognostic factor. However, little is known about the incidence of the translocation in relapsed patients and the duration of complete remission (CR) in children expressing the TEL/AML1 fusion gene. We therefore examined 49 bone marrow samples from children with ALL at first or second relapse that were consecutively mailed to our laboratory to test for the presence of t(12; 21) using reverse transcriptase (RT)-PCR. The TEL/AML1 rearrangement could be identified in nine of 44 (20%) of the patients, a result similar to the reported incidence at diagnosis. Most of the TEL/AML1–positive children showed no adverse clinical features at diagnosis (eg, white blood cell [WBC] count <100 × 109/L or age <10 years), and regarding these data, there were no differences versus children who were negative for the fusion gene. However, the period of remission was about 1 year longer in children expressing TEL/AML1 (P = .046), and the majority of relapses in this group appeared late (<2 years after diagnosis). Our findings therefore reinforce the urgent need for further prospective studies with a long follow-up period to determine the true prognostic significance of t(12; 21) and to avoid premature changes of treatment strategies.

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

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

Fine motor and handwriting problems after treatment for childhood acute lymphoblastic leukemia

Motor skills were investigated in 18 children 2 years after treatment for acute lymphoblastic leukemia (ALL). Gross and fine motor functioning were examined with the Movement Assessment Battery for Children. Handwriting as a specific fine motor skill was studied with a computerized writing task. We conclude that 2 years after cessation of treatment motor problems in ALL survivors were still present. Dysfunctions were mainly pronounced in handwriting and fine motor skills.

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

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

Magnetic resonance imaging and magnetic resonance angiography in long term survivors of acute lymphoblastic leukemia treated with cranial irradiation

BACKGROUND

Successful treatment of acute lymphoblastic leukemia (ALL) has resulted in an increasing number of patients whose disease is cured. This treatment includes cranial irradiation as prophylaxis against central nervous system relapse. The late effects of irradiation are well documented, but their incidence is unknown. The authors investigated the late effects of this treatment modality further by scanning 35 long term survivors of ALL who received cranial irradiation.

METHODS

Thirty-five survivors of ALL with no known complication of treatment were included in this study. They were examined with magnetic resonance imaging (MRI) of the brain and magnetic resonance angiography (MRA) of the circle of Willis. A control group of 24 patients who were cured of other childhood malignancies without exposure to cranial irradiation also were scanned.

RESULTS

Fifteen of 35 (43%) abnormalities were found in the study group versus 4/24 (17%) in the control group. Excluding minor atrophic changes that are known to be produced by irradiation and chemotherapy, there were 9/35 (26%) abnormalities in the study group and 1/24 (4%) in the control group (P < 0.05). These abnormalities included three tumors, a meningioma, a paranasal sinus rhabdomyosarcoma, and an anaplastic astrocytoma. In addition, there were two cases of large vessel vasculopathy, two small cystic infarcts, one diffuse white matter abnormality, and one cryptic vascular malformation. The abnormal control patient had a cerebellar infarct.

CONCLUSION

Complications of cranial irradiation in the treatment of ALL appear to be more frequent than currently are appreciated. That these complications include tumors that are potentially treatable suggests that screening may be valuable for these patients.

A comparison of the effects of methotrexate and misonidazole on the germinal cells of the subependymal plate of the rat

The cytotoxic effects of the drugs methotrexate (MTX) and misonidazole have been assessed in the rat brain by quantifying changes in the constituent cell populations of a glial cell progenitor layer, the subependymal plate (SEP). Three distinct cell types can be identified in the SEP on the basis of their nuclear morphology: cells with small dark (SD), small light (SL) or large light (LL) nuclei. The cells with SD nuclei may present pluripotential glial cell precursors. A reduction in the total nuclear density of the SEP, after the local ventricular administration of MTX, could be accounted for largely by a loss of cells with SD nuclei; to approximately 45% of control values 2 days after MTX followed by a full recovery in numbers by day 5. A further decline in the number of cells with SD nuclei occurred at 12 weeks after MTX administration. The pattern of changes in the cellularity of the SEP, after misonidazole administration, were similar to those observed after MTX treatment, although the magnitude of the response was reduced. It was concluded that both drugs, but MTX in particular, could have a potential additive effect on glial progenitor cells when used in combination with other forms of cancer therapy including radiation.

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.

Unusual case of leukoencephalopathy after bone marrow transplantation

A girl with chronic myeloid leukemia received bone marrow transplantation with total body irradiation as part of a conditioning regimen. She developed leukoencephalopathy about 50 days after transplant. There was permanent neurologic impairment afterward. She had not received any cranial irradiation or intrathecal chemotherapy before transplant. She had received 10 months of interferon treatment before transplant, which might have played a part in the development of leukoencephalopathy.

Association of 1800 cGy cranial irradiation with intellectual function in children with acute lymphoblastic leukaemia. ISPACC. International Study Group on Psychosocial Aspects of Childhood Cancer

Cranial radiation therapy in childhood acute lymphoblastic leukaemia has been associated with adverse neuropsychological effects, such as low intelligence. However, records show that these associations usually occur when the dose of radiation used is 2400 cGy. We investigated whether a lower dose of 1800 cGy had the same adverse effects on long-term survivors and whether high doses of methotrexate but no radiation therapy would have a more beneficial effect. We evaluated 203 children for six years in a multi-centre European study. The patients were divided into two groups: 129 children treated with 1800 cGy of cranial radiation therapy and 74 children who received high-dose methotrexate but no radiation therapy. We used full scale intelligence quotient, verbal, and performance IQ tests to assess the patient's intelligence. We found a significant decline in full scale intelligence quotient in the irradiated group that increased with the length of time from diagnosis. Younger age at diagnosis was associated with lower full scale intelligence quotient in the radiated group. Our results indicate that a radiation dose of 1800 cGy can have negative effects on neurocognitive function and we continue to question the benefit of low-dose cranial radiation therapy.

Central nervous system directed therapy in acute lymphoblastic leukaemia

CNS-directed treatment is an essential component of therapy for both children and adults with acute lymphoblastic leukaemia. The choice between combinations of i.t. drugs, radiotherapy and high-dose systemic chemotherapy is not a clear one and will depend on the age of the patient, the type of leukaemia and indeed the available treatment facilities. A plea is made for any prospective trials of CNS-directed therapy to incorporate formal assessment of neuropsychological performance, and in the young child, of growth and pubertal progression.

Functional neurological outcome in leukaemic children receiving repeated cranial irradiation

Long-term outcome defined by educational or employment history has been recorded in a group of children with acute lymphoblastic leukaemia (ALL) who received cranial radiotherapy at some stage prior to TBI conditioned bone marrow transplant (BMT). Median follow-up in 24 survivors of 69 consecutive patients was 4 years and 2 months. Individual risk factors for poor functional outcome were considered, including calculations of biological effective radiation doses. There was no incidence of CNS treatment-related mortality. All survivors are in normal school or employment, although three who had CNS relapse are receiving remedial teaching. No individual risk factors could be identified but the worst outcome was seen in children who were of young age at the time of initial treatment, who suffered CNS relapse and who had received the highest total dose of cranial irradiation.

Neuropsychological and neurological outcome after relapse of lymphoblastic leukaemia

Fourteen children who relapsed after initial remission of leukaemia were studied. Six received a second course of cranial radiotherapy, while the remaining eight children were given total body irradiation before bone marrow transplantation. The postirradiation somnolence syndrome was common after cranial radiotherapy. All children had mild/soft neurological signs, mostly of coordination. None had a major motor disability. All but the youngest child had cataracts; two children required an operation for these. All children were growth hormone deficient. Verbal IQ, attention, and concentration were selectively reduced (with respect to normative levels). The time between the two treatments, age at relapse, and higher doses of radiotherapy all correlated with cognitive outcome, with girls showing greater impairments than boys. Only two children were performing at age appropriate levels on measures of academic achievement. It is concluded that neurological and neuropsychological morbidity is significantly increased by the current treatments prescribed after the relapse of leukaemia.

Late sequelae in children treated for brain tumors and leukemia

Forty-two survivors treated at an age of 2-16 years for brain tumors or leukemia were, 4-21 years after treatment, subjected to an extensive follow-up investigation, including physical examination and interview; 35 of them also had endocrinological and 33 psychological evaluation. Hormonal deficiencies were found in about two-thirds of patients and were most common in those treated for brain tumors. The great majority had verbal intelligence quotient (VIQ) within normal range. Also, the performance intelligence quotients (PIQ) were normal in most patients. However, the results suggested that the primary intellectual capacity in children treated for cancer was not being fully utilized, their PIQ being on the average higher than their VIQ; this tendency was especially pronounced in the leukemia patients.

An odyssey in search of a cure: the evolution of treatment of childhood acute lymphoblastic leukemia in the United Kingdom

This review charts the evolution of therapy for childhood acute lymphoblastic leukaemia (ALL) in the United Kingdom. The present chemotherapeutic regimen is the result of experience gained from carefully planned randomised cooperative studies carried out during the last two decades. In common with the experience of the West German and American groups, the best results have been in those treated with post remission intensification blocks. With current chemotherapy protocols, almost 70% of children with ALL in U.K. can be cured but there may be a medical cost of such a cure, in terms of both acute and long term toxicity. This was especially true when central nervous system (CNS) therapy with cranial irradiation was used. Therefore present regimens are examining chemotherapeutic options for CNS disease control and the efficacy of additional post remission intensification. Failure of chemotherapy is most often seen in those children with a presenting white cell count of more than 50 x 10(9)/l, very young children and/or the presence of certain chromosomal rearrangements (e.g. t4: 11, t9: 22). At present the optimum therapeutic option for such high risk patients and for the majority of those in second remission, is an allogenic bone marrow transplant if an HLA-matched sibling is available. Modern day therapy is both complicated and costly and will be beyond the resources available for most children with ALL in developing countries. A significant decrease in worldwide mortality due to ALL will only occur if either the disease can be prevented or a simpler cure devised.

Unusual seizures with a benign course in a case of acute lymphoblastic leukemia of childhood

We report the unusual seizures in a patient with acute lymphoblastic leukemia. The convulsive disorder began acutely as partial somatomotor status epilepticus and with diffuse EEG slowing. The seizures then became myoclonic-atonic (drop attacks) and an EEG focus appeared on the left paramedian centro-parietal areas, activated by proprioceptive stimuli. Despite the severity of the clinical picture at onset, the seizures showed a benign course, and disappeared on carbamazepine therapy. We think that this epileptic syndrome may have been caused by diffuse iatrogenic encephalopathy, probably related to intrathecal methotrexate therapy.

Cranial computed tomography in children with acute lymphoblastic leukemia after prophylactic treatment with cranial radiation therapy and intrathecal methotrexate

BACKGROUND AND METHODS

Thirty-one children with acute lymphoblastic leukemia (ALL) who had received cranial radiation therapy (CrRT) and five concomitant doses of intrathecal methotrexate (IT MTX) for central nervous system prophylaxis (CNSP) and who had an event-free survival exceeding 5 years had cranial computed tomography (Cr CT) examination. The fractional dose for 21 of them was 1.5 Gy. The interval between the completion of CNSP and the time of Cr CT ranged from 5 to 8.5 years, with a median of 5 years 2 months.

RESULTS

Unlike the previous reports in the literature that 9-77% of children with ALL who had received Cr RT 18 Gy and IT MTX as CNSP had CT scan abnormalities, in this study no patient had CT scan abnormalities.

CONCLUSIONS

Our results might be attributable to the fractional dose of Cr RT being adequate, the IT chemotherapy being suitable, and the systemic chemotherapy not being intensive.

Clinical neurological findings of children with acute lymphoblastic leukaemia at diagnosis and during treatment

Serial neurological evaluation was performed on 40 consecutive children with acute lymphoblastic leukaemia (ALL) at the time of diagnosis and during treatment. Abnormal neurological signs were found in 23% of the patients, including some without neurological symptoms on admission. Six patients (15%) had abnormal funduscopy findings, papilloedema or preretinal haemorrhages, and 3 of them had increased intracranial pressure measured in connection with a diagnostic lumbar puncture but without blasts in their CSF. The reason for the increased intracranial pressure remained unclear. The development of neurological symptoms caused by peripheral neuropathy during induction therapy was related to the total dose and duration of vincristine therapy. The most severe walking difficulties, patients moving about on all fours for as long as 6 weeks-5 months, occurred in a group who were significantly younger than the other children (P < 0.03). Fine and gross motor disturbances occurred in 18% and 30% of the whole patient group, respectively, after 2-3 years of therapy. Impaired short-term memory was observed in 21% of the patients after 2-3 years of therapy, indicating impaired CNS function. The results indicate that chemotherapy also seems to influence CNS abilities, since there was no significant difference between the patients treated with or without cranial irradiation. Neurological evaluation of children with ALL at diagnosis and during treatment is of value with respect to abnormal findings which persist and are not caused by leukaemia, in order to determine the types of difficulties involved and to consider intervention.

White matter changes in children treated for acute lymphoblastic leukemia

BACKGROUND AND METHODS

Twenty-seven children with acute lymphoblastic leukemia (ALL) were studied by magnetic resonance (MR) imaging after central nervous system (CNS) treatment. The children were followed by clinical evaluations and computed tomographic (CT) brain scans. Two CNS treatment techniques were used. Eleven patients received intravenous and intrathecal methotrexate; 16 patients received 18-30 Gy of cranial radiation therapy in addition to systemic chemotherapy. The time interval between the CNS treatment and MR scans varied from 9 months to 4 years 8 months.

RESULTS

Four of the 27 children (15%) showed white matter changes on the MR scans attributable to therapy, but only one had hypodensity on CT. Three of the 16 children (19%) receiving radiation therapy in addition to chemotherapy had white matter changes. One of the 11 patients (9%) from the group receiving only chemotherapy did so. The difference between the two treatment groups was not significant.

CONCLUSIONS

Radiation therapy or chemotherapy (alone or in combination) may have been responsible for the white matter changes. MR imaging is a sensitive detector of white matter changes in children with ALL, but its value and significance during follow-up should be assessed in well-designed longitudinal research studies.

Leukaemia in the young child

Leukaemia is rare in infancy with an equal predominance of lymphoblastic and myeloblastic cases. Acute lymphoblastic leukaemia in infants under one year is characterised by a high leucocyte count, organomegaly, early B-cell phenotype, sometimes with evidence of monocytoid differentiation and cytogenetic abnormalities. This is reflected in its poor prognosis. The toddler (aged 1-2) tends to develop typical childhood ALL which is responsive to treatment, but remains vulnerable to late effects of therapy, particularly radiation. The distribution of subtypes of AML differs in the younger and older child and results of treatment have improved in all age groups. A uniform strategy appears desirable for all cases of childhood AML. It seems probable that different genetic and environmental factors may be involved in the genesis of infant ALL, childhood ALL and AML in children. The management of leukaemia in children under two poses a considerable challenge.

Cranial computed tomographic findings in children with newly diagnosed acute lymphoblastic leukemia: a prospective follow-up study during treatment

Cranial computed tomography (CT) was performed on 40 consecutive children with newly diagnosed acute lymphoblastic leukemia (ALL) on admission before any chemotherapy, 5 months after CNS therapy (n = 39) and after 2 to 3 years of therapy (n = 31). Changes related to leukemia were found in only 10% of the patients at the time of diagnosis (4/40). These initial changes, two intracranial hemorrhages, one dural thickening and one contrast enhancement, all disappeared during therapy. The findings which persisted unchanged in the next two CT scans were thought to be normal variations or caused by earlier disorders. CNS therapy consisted of intrathecally and intravenously administered methotrexate in 20 standard risk (SR) patients and cranial irradiation in addition to chemotherapy in 19 intermediate risk (IR) or high risk (HR) patients. Four SR patients developed changes during therapy. Three had enlarged cerebrospinal fluid (CSF) spaces and one developed a focal low density area suggesting disturbances in brain blood circulation and also experienced disturbances in level of consciousness. Of the 19 IR or HR patients, eight developed changes related to the therapy, including four with white matter hypodensity areas, of whom three also had enlarged CSF spaces, and four others who developed enlarged CSF spaces. The medians of the widths of the cortical sulci (P less than .001), insular cisterns (P less than .01), third ventricles (P less than .01), and frontal horns (P less than .05), and also of Evans' ratios (P less than .05) increased significantly after CNS therapy as compared with the findings at diagnosis in the patients who had received cranial irradiation. Most of these changes persisted during the follow-up. We conclude that the clinical value of CT scanning during therapy for ALL is restricted to patients with neurological symptoms or those who have undergone CNS irradiation.

Prophylactic cranial irradiation dose effects on late cognitive function in children treated for acute lymphoblastic leukemia

Prophylactic central nervous system treatment has dramatically improved the disease-free survival of children with acute lymphoblastic leukemia (ALL). Long-term neuropsychological sequelae are documented in children who received 2400 cGy prophylactic cranial irradiation. The dose was reduced to 1800 cGy. Available reports on developmental consequences, with short follow-up, have yielded inconsistent results. This study assesses radiation dose effects on cognitive function in children with leukemia who received central nervous system prophylaxis with 2400 cGy versus 1800 cGy whole brain radiotherapy. All leukemic children also received intrathecal methotrexate. A control group of children (treated for Wilms' tumor) received no central nervous system therapy. Nineteen children were treated with 2400 cGy, 16 children with 1800 cGy. The 12 control children received no irradiation. All patients were off therapy for at least 70 months. The 1800 cGy and 2400 cGy patient groups were off therapy for equivalent periods of time (range 70-123 mo) at follow-up testing. Mean age at diagnosis was 49 months, at testing: 142 months. The male to female ratio was 1/1. Standardized psychological tests were administered. Full-Scale, Verbal, and Performance IQ were measured with the Wechsler Intelligence Scale for Children-Revised. Wide Range Achievement Testing evaluated reading, spelling, and arithmetic abilities. Children treated with 1800 cGy performed significantly better than those who received 2400 cGy, and at the same level as controls. There were statistically significant differences between the 1800 cGy and 2400 cGy subjects in all measures. 2400 cGy patients had deficiencies in IQ and academic performance. 1800 cGy patients scored approximately 12 points higher than 2400 cGy children. Eleven children, two in the control group, two in the 1800 cGy, and seven in the 2400 cGy group had IQ scores of less than 90. Eight of the nine irradiated children with deficits had radiotherapy before age 5. These results indicate a mild, but diffuse information processing deficit in children who received 2400 cGy, but not in children who received 1800 cGy. These findings with a minimum of 6 years of follow-up provide new information on late effects of CNS prophylaxis in ALL. Reducing the cranial RT dose from 2400 cGy to 1800 cGy reduced neurotoxicity to acceptable levels.