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

A Comprehensive Review of Neuropsychologic Studies Supports the Concept That Adequate Folinic Acid Rescue Prevents Post Methotrexate Neurotoxicity

PURPOSE

To review all studies providing evidence of the correlation between folinic acid (FA) rescue inadequacy and long-term cognitive damage in neuropsychological studies of children with acute lymphoblastic leukemia or osteogenic sarcoma treated under protocols using high-dose methotrexate and FA rescue.

METHODS

A comprehensive literature search was performed of all databases of the Web of Science Citation Index, during 1990-2020, for the terms: neuropsychological, neurocognitive, and cognitive, together with acute lymphoblastic (and lymphocytic) leukemia and osteogenic sarcoma. English-language peer-reviewed articles on neuropsychological assessments of children who had been treated with high-dose methotrexate without irradiation, and which included details of methotrexate and FA schedules, were selected. In addition, a personal database of over 500 reprints of articles from over 130 journals was reviewed on the subjects of methotrexate and FA and their side effects.

RESULTS

Three groups of studies were found and analyzed, with (1) no evidence of cognitive deterioration, (2) evidence of cognitive deterioration, and (3) more than 1 protocol grouped together, preventing separate analysis of any protocols, Protocols without cognitive deterioration reported adequate FA rescue, and those with cognitive deterioration reported inadequate FA rescue.

CONCLUSION

Neuropsychological evaluation supported inadequate FA being the cause of neurocognitive damage after high-dose methotrexate and that adequate FA rescue prevents this complication.

Cranial MRI in Childhood Acute Leukemia during Treatment and Follow-Up Including the Impact of Intrathecal MTX-A Single-Center Study and Review of the Literature

Due to high survival rates, long-term sequelae, especially neurotoxicity, need to be considered in childhood acute leukemias. In this retrospective analysis of morphologic changes of the brain in children treated for acute leukemias, we included 94 patients (77 ALL, 17 AML; 51 male, 43 female; median age: 5 years) from a single center. We analyzed 170 cranial MRI scans (T2, FLAIR axial) for morphologic alterations of the brain and variations of the ventricular width (GDAH). In addition, the corresponding literature was reviewed. More than 50% of all patients showed cerebral pathomorphologies (CP). They were seen more often in children with ALL (55.8%), ≤ 6 years of age (60.8%), in relapse (58.8%) or after CNS irradiation (75.0%) and included white matter changes, brain atrophy, sinus vein thrombosis and ischemic events. GDAH significantly enlarged mainly in children up to 6 years, with relapse, high-risk leukemias or ALL patients. However, GDAH can normalize again. The number of intrathecal Methotrexate applications (≤12 vs. >12) showed no correlation to morphologic alterations besides a significant increase in GDAH (−0.3 vs. 0.9 mm) between the first and last follow-up MRI in ALL patients receiving >12 ith. MTX applications. The role of ith. MTX on CP needs to be further investigated and correlated to the neurocognitive outcome of children with acute leukemias.

Etiology and Outcome of Seizures in Children during Induction Remission Chemotherapy for Acute Lymphoblastic Leukaemia

Seizure is one of the most frequent neurological complication and morbid phenomenon among children receiving chemotherapy for acute lymphoblastic leukemia. As overall survival of children with acute lymphoblastic leukemia is improving, now the challenge is to reduce treatment-related adverse effect. However, not much is known about the etiology and natural history of these seizure in our pediatric population. This is a single centered study conducted in the Department of Pediatric Hematology and Oncology, Bangabandhu Sheikh Mujib Medical University. This prospective observational study was conducted over a period of 1 year from May 2017 to April 2018. A total of 105 patients aged 1 year to 17.9 years newly diagnosed as acute lymphoblastic leukemia were the study population. This study showed that in five (33.3%) patients, the underlying cause was suspected intracranial hemorrhage and it was the most common cause. All these five patients had features of severe sepsis and upper motor neuron sign associated with severe thrombocytopenia. Among them three had coagulopathy. Three (20%) patients had CNS leukemic infiltration. Suspected meningitis was attributed as the possible cause of seizure in two (13.33%) patients. Other identifiable causes were brain abscess in one patient, multiple cerebral infarction in one patient, hypertensive encephalopathy in one patient, and vincristine-induced neurotoxicity in one patient. In one patient no identifiable cause was found. Among 15 patients with seizure five (33.3%) patients were improved and completed induction remission chemotherapy. Ten (66.7%) patients died. In this study, we found sepsis and coagulopathy as the major underlying cause of seizure. Outcome was found very dismal in patients who developed seizure.

Hyperleukocytosis-induced stroke and tonsillar herniation: Case report

Introduction

and Importance: Acute ischemic stroke is a rare event in children with leukemia, yet with long-term morbidity, substantial health, and economic cost. Central nervous system (CNS) leukemic involvement and chemotherapy-related stroke are the most common causes. Hyperleukocytosis induced stroke is very rarely reported.

Case presentation

A 2-year-old male child presented with hyperleukocytosis (leukocyte count was 320x10⁹/L). Bone marrow evaluation revealed T-cell acute lymphoblastic leukemia. He was treated with dexamethasone, vincristine and daunorubicin, and on day 4 of chemotherapy, he developed abnormal movements, altered mental status, limb weakness and mutism. Magnetic resonance imaging of the brain showed multifocal infarctions involving left pons and both cerebellar hemispheres causing tonsillar herniation with restricted diffusion and mild hydrocephalus but no leptomeningeal enhancement or leukemic infiltrates. Magnetic resonance angiography did not show any arterial stenosis. He was intubated, sedated and managed conservatively with dexamethasone. Cytologic analysis of cerebrospinal fluid showed no blasts. Thrombophilia work up was negative. Five weeks later, the patient had significant improvement in overall neurologic status. He is free of leukemia. MRI showed interval resolution of previous infarcts.

Clinical discussion

Hyperviscosity secondary to hyperleukocytosis was considered to be the most likely explanation for this patient stroke after excluding thrombophilia and leukemic infiltration. Prompt management with hydration and careful chemotherapy resulted in good outcome in our patient.

Conclusion

This case demonstrate the value of early recognition and prompt management of posterior circulation ischemic stroke in children with leukemia and hyperleukocytosis at presentation.

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Hyperleukocytosis and hyperviscosity can result in arterial ischemic stroke

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Posterior circulation ischemic strokes are very rare in children with leukemia

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Posterior circulation stroke can carries potential risk of herniation

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Prompt recognition and management are essential in posterior circulation stroke

Folinic acid over rescue of high dose methotrexate: How problematic citations conserve discredited concepts

BACKGROUND

The outdated axiom that the dose of Folinic acid (FA) rescue used after high dose Methotrexate (HDMTX) should be kept to a minimum in order to prevent a reduction of prognosis ("over rescue") continues to be expressed even though the concept has been seriously challenged. Study aim The ways "problematic citations" are used to support an old theory, such as this, was examined.

RESULTS

Ten patterns of "problematic citation" use were identified. In 8 of these patterns the articles used were scientifically sound and the problem was with the articles citing them. However in 2 other pattens, the articles and their conclusions were flawed and citing them, apparently, resulted from accepting the presented data or conclusions as sound and valid. The patterns were 1. Claims based on data that are not present in the cited article. 2. Selective inclusion of data from cited articles. 3. Citation of misleading data presented only in the abstract. 4. Reporting trends as statistically significant. 5. Copying the citations used by others without checking the article. 6. Acceptance of illusionary truth in spite of knowledge to the contrary. 7. Citation of reports not relevant to the population under discussion 8. Presenting opinions as facts without any citation. 9. Selective presentation of data sets that support the thesis while ignoring the data sets that show the opposite results. 10. Use of a title expressing what the authors intended to show but not what was found.

IMPLICATIONS

The containing acceptance of this old insupportable conjecture, in part, because of "problematic citations" has resulted in unnecessary neurocognitive damage to patients and may have resulted in the misconception that it is the outcome of HDMTX that may have lead to its abandonment in favour of more toxic therapies. Realisation that this is a significant problem in data analysis should lead authors and reviewers to be even more carefully in checking all references. The importance of high-quality reviews is clearly evident. The effect of "Canonization of false facts" is a serious impairment to the acceptance of new hypotheses that better express reality and could lead to improved treatment results. Authors are advised only to cite articles they have read in entirety not relying on the title, abstract or previous use and to check the content of citations before submission.

Patterns, risk factors and outcome predictors of posterior reversible encephalopathy syndrome in pediatric cancer patients

The purpose of this study was to assess the clinical and radiological patterns and outcome predictors of posterior reversible encephalopathy syndrome (PRES) in pediatric cancer patients. A retrospective study included patients who developed PRES during their treatment at the Children's Cancer Hospital Egypt. A total of 50 patients developed PRES. Leukemia and lymphoma were the commonest diagnoses (64%). Regarding the MRI findings, occipital affection was the most common (92%), followed by frontal and temporal lobes involvement in 32% and 22% respectively and advanced PRES was described in 8 patients. Of the whole patients, 80% had complete clinical resolution and 60% showed complete radiological resolution at 2 weeks' evaluation and 2 patients died out of PRES. Unfavorable outcome was associated with those who had motor dysfunction, status epilepticus at presentation, frontal lobe and thalamic affection and atypical PRES. PRES might present in atypical sites with poor outcome including death.

The spectrum of acute central nervous system symptoms during the treatment of childhood acute lymphoblastic leukaemia

BACKGROUND

Children with central nervous system (CNS) toxicity during therapy for acute lymphoblastic leukaemia (ALL) are at risk for treatment modifications, long-term sequelae and even higher mortality. A better understanding of CNS symptoms and their complications improves the potential to prevent and treat them.

METHODS

Patient files from 649 children treated with Nordic Society of Pediatric Hematology and Oncology ALL92 and ALL2000 protocols in Finland were reviewed retrospectively for any acute CNS symptom. Detailed data on symptoms, examinations and treatment of the underlying CNS complications were collected from the medical records. Disease-related and outcome data were retrieved from the Nordic leukaemia registry.

RESULTS

Altogether, 13% (86) of patients with ALL had acute CNS symptoms. Most symptoms (64%) occurred during the first 2 months of therapy. Posterior reversible encephalopathy syndrome was the most frequent complication (4.5%). Cerebrovascular events were diagnosed in 10 cases (1.6%), while methotrexate-related stroke-like syndrome (SLS) was observed in only one patient (0.2%). CNS symptoms due to systemic or unclear conditions, especially sepsis, were important for differential diagnosis. CNS leukaemia was associated with CNS symptoms (hazard ratio [HR] = 4.03; P = .003), and epilepsy was a common sequel of CNS complications (19%).

CONCLUSIONS

Acute CNS symptoms are common during ALL therapy, occurring mainly during the first 2 months of treatment. Patients with CNS leukaemia at diagnosis are at a higher risk for CNS toxicity. Despite intensive CNS-directed methotrexate treatment, SLS was diagnosed extremely rarely in our series.

Neurotoxicity after high-dose methotrexate (MTX) is adequately explained by insufficient folinic acid rescue

PURPOSE

To challenge the view that the dose of folinic acid rescue after high-dose methotrexate (MTX) has no significance in the prevention of neurotoxicity and to present the minority view that neurotoxicity can be prevented by an adequate dose of folinic acid, without compromising treatment results. Several fallacies that led to the misunderstanding of post MTX neurotoxicity are presented.

METHODS

Data mining using search engines was used to find relevant publications, and an e-mail survey of more than 60 authors of articles in this field was performed. All relevant articles identified were read in their entirety.

RESULTS

Examples of clinical studies with neurotoxicity following inadequate rescue are given. Some studies demonstrated no neurotoxicity when adequate doses of folinic acid rescue were started 24-36 h after the start of HDMTX rescue even after mega doses of MTX. Rescue started after 42 h was associated with neurotoxicity except in patients with low serum MTX levels after 24 and 36 h. ALL protocols with neurotoxicity, especially BFM-like protocols, are presented. Protocol is reported in which single protocol changes prevented neurotoxicity.

CONCLUSIONS

From the published data, when folinic acid rescue is given in a sufficiently high enough dose and is started 24-36 h after the beginning of the methotrexate exposure, and virtually all forms of post MTX neurotoxicity can be prevented without compromising therapeutic results.

Magnetic Resonance Imaging of Pediatric Neurologic Emergencies

Although computed tomography is often the first line of imaging in the emergency setting, magnetic resonance imaging (MRI) is of increasing importance in the evaluation of central nervous system emergencies in the pediatric population. As such, it is necessary to understand the indications for which MRI may be necessary. This article reviews the unique pathophysiologic entities affecting the pediatric population and the associated MRI findings. Specifically, utility of emergent MRI and characteristic appearances of traumatic brain injury, traumatic spinal injury, nonaccidental trauma, arterial ischemic stroke, cerebral sinovenous thrombosis, stroke mimics, and central nervous system infections are described.

Acute Central Nervous System Complications in Pediatric Acute Lymphoblastic Leukemia

BACKGROUND

The outcome of childhood acute lymphoblastic leukemia has improved because of intensive chemotherapy and supportive care. The frequency of adverse events has also increased, but the data related to acute central nervous system complications during acute lymphoblastic leukemia treatment are sparse. The purpose of this study is to evaluate these complications and to determine their long term outcome.

PATIENTS AND METHODS

We retrospectively analyzed the hospital reports of 323 children with de novo acute lymphoblastic leukemia from a 13-year period for acute neurological complications. The central nervous system complications of leukemic involvement, peripheral neuropathy, and post-treatment late-onset encephalopathy, and neurocognitive defects were excluded.

RESULTS

Twenty-three of 323 children (7.1%) suffered from central nervous system complications during acute lymphoblastic leukemia treatment. The majority of these complications (n = 13/23; 56.5%) developed during the induction period. The complications included posterior reversible encephalopathy (n = 6), fungal abscess (n = 5), cerebrovascular lesions (n = 5), syndrome of inappropriate secretion of antidiuretic hormone (n = 4), and methotrexate encephalopathy (n = 3). Three of these 23 children (13%) died of central nervous system complications, one from an intracranial fungal abscess and the others from intracranial thrombosis. Seven of the survivors (n = 7/20; 35%) became epileptic and three of them had also developed mental and motor retardation.

CONCLUSIONS

Acute central neurological complications are varied and require an urgent approach for proper diagnosis and treatment. Collaboration among the hematologist, radiologist, neurologist, microbiologist, and neurosurgeon is essential to prevent fatal outcome and serious morbidity.

Methotrexate-induced chemical meningitis in patients with acute lymphoblastic leukemia/lymphoma

BACKGROUND

Intrathecal methotrexate (ITMTX) is an important component in the treatment as well as prophylaxis of leukemia/lymphoma. ITMTX can cause chemical meningitis characterized by vomiting, headache, and fever lasting 2-5 days with spontaneous resolution of symptoms which differentiates this syndrome from bacterial meningitis.

OBJECTIVE

This prospective observational study was carried out to determine incidence of post-ITMTX syndrome in patients receiving prophylactic ITMTX as part of Berlin-Frankfurt-Munster (BFM) protocol.

MATERIALS AND METHODS

Patients aged 15-50 years receiving BFM 90 or BFM 95 protocol for acute lymphoblastic leukemia or lymphoblastic lymphoma were followed up for post-ITMTX syndrome, defined as vomiting, headache and fever between 38° and 39°C following ITMTX.

RESULTS

Thirty-three patients received a total of 297 courses of ITMTX. Of the 297 doses of ITMTX, 20 episodes (6.7%) of post-ITMTX syndrome were observed. The incidence of post-ITMTX syndrome was highest after the second dose of ITMTX (24%). The most common symptom of post-ITMTX syndrome was headache which was seen in 17 (85%) patients. Seventeen (85%) patients had vomiting, 10 (50%) patients had fever, and 4 (20%) patients had backache. Meningeal signs were present in 2 (10%) patients.

CONCLUSIONS

Post-ITMTX syndrome is not uncommon in adult patients receiving prophylactic ITMTX for treatment of acute lymphoblastic leukemia and lymphoblastic lymphoma. Patients develop a toxic syndrome closely mimicking acute bacterial meningitis but spontaneous recovery is seen without any neurological sequelae.

Polymorphisms in Genes Related to Oxidative Stress Are Associated With Inferior Cognitive Function After Therapy for Childhood Acute Lymphoblastic Leukemia

PURPOSE

Survivors of childhood acute lymphoblastic leukemia (ALL) exhibit increased rates of neurocognitive deficits. This study was conducted to test whether interpatient variability in neurocognitive outcomes can be explained by polymorphisms in candidate genes conferring susceptibility to neurocognitive decline.

METHODS

Neurocognitive testing was conducted in 350 pediatric leukemia survivors, treated on Dana-Farber Cancer Institute ALL Consortium Protocols 95-01 or 00-01. Genomic DNA was isolated from bone marrow collected at remission. Candidate polymorphisms were selected on the basis of prior literature, targeting genes related to drug metabolism, oxidative damage, altered neurotransmission, neuroinflammation, and folate physiology. Single nucleotide polymorphisms were detected using either a customized multiplexed Sequenom MassARRAY assay or polymerase chain reaction-based allelic discrimination assays. Multivariable logistic regression models were used to estimate the effects of genotype on neurocognitive outcomes, adjusted for the effects of demographic and treatment variables. False-discovery rate correction was made for multiple hypothesis testing, indicated as a Q value.

RESULTS

Inferior cognitive or behavioral outcomes were associated with polymorphisms in three genes related to oxidative stress and/or neuroinflammation: NOS3 (IQ, Q = 0.008; Vocabulary Q = 0.011; Matrix Reasoning Q = 0.008), SLCO2A1 (IQ Q = 0.043; Digit Span Q = 0.006; Block Design Q = 0.076), and COMT (Behavioral Assessment System for Children-2 Attention Q = 0.080; and Hyperactivity Q = 0.084). Survivors homozygous for NOS3 894T, with at least one SLCO2A1 variant G allele or with at least one GSTP1 variant allele, had lower mean estimated IQ scores than those without these genotypes.

CONCLUSION

These data are consistent with the hypothesis that oxidative damage contributes to chemotherapy-associated neurocognitive decline among children with leukemia.

Central nervous system chemotoxicity during treatment of pediatric acute lymphoblastic leukemia/lymphoma

In the last decades, increasing success rates are being obtained in the chemotherapy of pediatric leukemia and lymphoma. However, the cornerstone of this treatment is still formed by a reduced number of drugs with a highly toxic profile. In particular, central nervous system complications remain a challenging clinical problem, requiring rapid detection and prompt treatment to limit permanent damage. Furthermore, clinicians are often challenged to discriminate between CNS involvement by the disease, toxicity of drugs or infections. This clinically oriented review will help recognize and handle the main neurologic adverse effects induced by chemotherapy in pediatric patients with lymphoblastic leukemia/lymphoma. Different clinical entities and putative drugs involved are discussed in each chapter, with clinical cases illustrating the most relevant and challenging events. In addition, specific clinical-radiological patterns of some of these neurologic events are detailed. Finally, the role of pharmacogenetics, with special focus on those polymorphisms that could help explain the occurrence of neurotoxicity, is also discussed.

Clinical features of encephalopathy in children with cancer requiring cranial magnetic resonance imaging

We analyzed acute neurotoxic problems attributable to chemotherapy or immunosuppression in the context of childhood neoplastic diseases, based on clinical and neuroradiologic findings. This retrospective single-center study reviewed the acute neurologic complications of 62 children receiving conventional chemotherapy or hematopoietic stem cell transplantation from July 2005-July 2008. We excluded patients with central nervous system metastasis and various neurotoxic manifestations not usually requiring cranial magnetic resonance imaging. Of 62 patients, 12 (19.3%) developed acute neurologic complications. The most common complications included posterior reversible encephalopathy syndrome in six of 12 (50%) patients, and Wernicke's encephalopathy in three of 12 (25%) patients. Other complications included chemical arachnoiditis, grey matter injury induced by postchemotherapeutic angiopathy, and leukoencephalopathy. Posterior reversible encephalopathy syndrome was accompanied by hypertensive episodes in most patients (5/6), and Wernicke's encephalopathy was evident with altered mental status in malnourished children. These data indicate that posterior reversible encephalopathy syndrome and Wernicke's encephalopathy are the predominant complications in children undergoing chemotherapy or hematopoietic stem cell transplantation. Early radiologic and clinical evaluation and prompt treatment for these complications are necessary to prevent their progression to irreversible brain damage.

The mystery of electroencephalography in acute lymphoblastic leukemia

The aim of the study was to evaluate changes in electroencephalogram (EEG) recordings during the course of acute lymphoblastic leukemia (ALL) in children. The study group consisted of 48 children with ALL who underwent a total of 72 EEGs at various stages of the disease. The medical files were reviewed for pertinent clinical data, and the EEGs were evaluated for changes in brain activity. Abnormal background activity was noted in 52.2% of the EEGs done at 1-10 days of therapy, in 43.5% of those done at 10-60 days, and only 4.3% of those done at later stages (p=0.037). These findings, together with earlier reports, suggest that early-stage ALL, even before treatment, may be associated with excessive slow EEG activity, which improves over time. The EEG changes, by themselves, are not an indication of central nervous system leukemia or a predictor of later seizures or other central nervous system involvement.

Somatosensory evoked potential for detection of subclinical neuropathy in Egyptian children with acute lymphoblastic leukaemia

To evaluate neurological changes developing during paediatric Acute Lymphoblastic Leukaemia (ALL) therapy clinically and through electrophysiological Study of Somatosensory Evoked Potentials (SSEPs) changes in different phases of therapy. Thirty five-ALL patients with age range from 3-14 years were included compared to 30 healthy controls. History, neurological examination, complete blood counts, cytological examination of bone marrow aspirate and cerebrospinal fluid with Measurement of Serum Methotrexate (MTX) were done. The SSEPs were performed and patients subjected to another SSEP with measurement of serum MTX level before and 10 days after intra-thecal injection (IMTX). Clinical neurological findings in patients after induction were depressed deep tendon reflexes (43.3%), hypotonia (28.6%), lost pain sensation (28.6%), muscle weakness (17.1%) and movement disorders (17.1%). Percentage of delayed SSEPs after induction were at levels of brachial plexus (28.6%), spinal cord (68.6%), cortical conduction (31.4%), ERB-N13 Inter Peak Latency (IPL) (74.3%) and N13-N20 IPL (17.1%) in the studied patients. Significant prolonged latency of N13 (p = 0.005), N20 (p = 0.04) and IPL of ERB-N 13 (p = 0.005), N13-N20 (p = 0.01), Inter-Side Difference (ISD) of N13 (p = 0.01), ERB-N13 (p = 0.02) and N13-N20 (p = 0.03) after induction compared to values at diagnosis. Significant positive correlation were found between serum MTX after IMTX with N13-N20 IPL (p = 0.01), N20 ISD (p = 0.03) with significant prolongation in N20 latency, N13-N20 IPL and ISD of N20 compared to values before injection. ALL patients have prolonged latency of SSEPs at cervical cord and cortical levels which increased after IMTX due to axonal injury throughout the cord. SSEPs could be an early diagnostic tool for subclinical neuropathy.

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.

No role for cerebrospinal fluid myelin basic protein levels in patients treated for childhood acute lymphoblastic leukemia

INTRODUCTION

Central nervous system prophylaxis of childhood acute lymphoblastic leukemia has dropped rates of relapses but has been associated with neurotoxicity and imaging abnormalities. Predictors of neurotoxicity are lacking, because of inconsistency between clinical symptoms and imaging. Some have suggested that cerebrospinal fluid myelin basic protein (MBP) levels to be of potential interest. A retrospective analysis of MBP levels in correlation with clinical and radiologic data is presented.

MATERIALS AND METHODS

MBP levels obtained at the time of intrathecals, charts, and neuroradiology reports were retrospectively analyzed. Academic achievement data were obtained from phone contacts with patients and families.

RESULTS

We retrieved 1248 dosages of MBP in 83 patients, 381 neurologic examinations in 34 patients and 69 neuroradiologic investigations in 27 patients. Fifty-two patients had abnormal MBP levels. Radiologic anomalies were present in 47% of those investigated, 14% of them having school difficulties. Proportions of patients with school difficulties in the groups with abnormal MBP levels but no radiologic anomalies or with no radiologic investigations were 0% and 3%, respectively, which was lower than in the group of patients with normal MBP levels (100%, 22%, and 5%, respectively).

DISCUSSION

Notwithstanding the retrospective character of our study, we conclude that there is limited usefulness of systematic dosage of MBP as indicator of treatment-induced neurotoxicity in acute lymphoblastic leukemia patients.

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.

Folate homeostasis in cerebrospinal fluid during therapy for acute lymphoblastic leukemia

The neurotoxic effects of therapy for childhood acute lymphoblastic leukemia can result in leukoencephalopathy or measurable deficits in cognitive function. However, there are no validated biomarkers that allow the identification of those patients at greatest risk. With the objective of identifying such predictors, cerebrospinal fluid collected from 53 patients over 2.5 years of therapy for childhood acute lymphoblastic leukemia was retrospectively studied. Cerebrospinal fluid folate, concentrated relative to serum folate prior to therapy, dropped during the first month of therapy and remained below baseline throughout treatment. Cerebrospinal fluid homocysteine was inversely related to cognitive function prior to treatment. Oral methotrexate was associated with decreased cerebrospinal fluid folate and increased cerebrospinal fluid homocysteine, but these changes were not seen with oral aminopterin. Of 36 patients who had imaging after completion of therapy, 9 had periventricular or subcortical white matter abnormalities consistent with leukoencephalopathy. Peak cerebrospinal fluid tau concentrations during therapy were higher among patients who had leukoencephalopathy after completion of therapy than among those with normal imaging studies at the end of therapy. If confirmed prospectively, these markers may allow the identification of those patients at greatest risk of developing treatment-induced neurocognitive dysfunction, thus guiding preventive interventions.

Age and high-dose methotrexate are associated to clinical acute encephalopathy in FRALLE 93 trial for acute lymphoblastic leukemia in children

The objective of the study was to assess acute neurotoxicity associated with triple intrathecal therapy (TIT)+/-high-dose methotrexate (HD MTX) in children with acute lymphoblastic leukemia (ALL). 1395 children were enrolled on FRALLE 93 protocol from 1993 to 1999. Lower-risk group (LR, n=182) were randomized to weekly low-dose MTX at 25 mg/m(2)/week (LD MTX, n=81) or HD MTX at 1.5 g/m(2)/2 weeks x 6 (n=77). Intermediate-risk group (IR, n=672) were randomized to LD MTX (n=290) or HD MTX at 8 g/m(2)/2 weeks x 4 (n=316). Higher-risk group (HR, n=541) prednisone-responder patients received LD MTX and cranial radiotherapy. HR group steroid resistant cases were grafted (autologous or allogenic). TIT (MTX, cytarabine and methylprednisolone) was given every 2 weeks during 16-18 weeks and every 3 months during maintenance therapy in LR and IR patients. 52 patients (3.7%) developed neurotoxicity. Isolated seizures: n=15 (1.1%), peripheral and spinal neuropathy: n=17 (1.2%) and encephalopathy: n=20 (1.4%). Age >10 years was significantly associated with neurotoxicity (P=0.01) and use of HD MTX is associated with encephalopathy (P=0.03). Sequels are reported respectively in 60 and 33% of spinal neuropathy and encephalopathy cases. Current strategies tailoring risk of neurological sequels has to be defined.

Methotrexate induces seizure and decreases glutamate uptake in brain slices: Prevention by ionotropic glutamate receptors antagonists and adenosine

Methotrexate (MTX)-induced neurotoxicity may occur after intrathecal or systemic administration at low, intermediate and high doses for the treatment of malignant or inflammatory diseases. The mechanisms of MTX neurotoxicity are not totally understood, and appear to be multifactorial. In this study we characterized a model of MTX-induced seizures in mice to evaluate the convulsive and toxic MTX properties. Additionally, the effect of MTX-induced seizures on the activity of glutamate transporters, as well as the anticonvulsant role of MK-801, DNQX and adenosine on glutamate uptake in brain slices was investigated . MTX induced tonic-clonic seizures in approximately 95% of animals and pre-treatment with MK-801, DNQX and adenosine prevented seizure in 80%, 62% and 50% of animals, respectively. Moreover, MTX leads 59% of mice to death, which was prevented in 100% and 94% when animals received MK-801 and DNQX, respectively. Glutamate uptake decreased by 20% to 30% in cortical slices after MTX-induced seizures. Interestingly, when seizures were prevented by MK-801, DNQX or adenosine, glutamate uptake activity remained at the same level as the control group. Thus, our results demonstrate the involvement of the glutamatergic system in MTX-induced seizures.

The neurologic complications in pediatric acute lymphoblastic leukemia patients excluding leukemic infiltration

This study presents retrospective analyses of 20 acute lymphoblastic leukemia (ALL) patients who developed neurologic complications (except leukemic infiltration). These subjects represent 9.9% of 203 ALL patients aged 16 years or younger followed in our hospital between March 1991 and January 2003. Fourteen male and six female patients, whose ages ranged between 6 and 168 months, developed 24 episodes of neurologic complications after the diagnosis of ALL. The most common complication was meningitis, which developed in six (25%) episodes, and two thirds of the patients who had meningitis were evaluated to be iatrogenic. Cerebral infarct and venous thrombosis were detected in five (21%) of the episodes. In two (8%) episodes progressive cerebral dysfunction developed after radiotherapy. The remaining 11 (45%) episodes are due to varying types of complications. Interestingly, one patient had abundant histiocytes exhibiting hemophagocytosis in the cerebrospinal fluid (CSF) examination and this patient was subsequently diagnosed with fungal meningoencephalitis, by further investigation. Six (30%) patients died; epilepsia developed in five (25%) patients in the follow-up period and the remaining nine (45%) are healthy. By close follow-up and effective treatment of thrombosis and, especially, of infections including iatrogenic meningitis in developing countries, the morbidities and mortalities of these complications can be decreased.

Reversible acute methotrexate leukoencephalopathy: atypical brain MR imaging features

BACKGROUND

Unusual acute symptomatic and reversible early-delayed leukoencephalopathy has been reported to be induced by methotrexate (MTX).

OBJECTIVE

We aimed to identify the occurrence of such atypical MTX neurotoxicity in children and document its MR presentation.

MATERIALS AND METHODS

We retrospectively reviewed the clinical findings and brain MRI obtained in 90 children treated with MTX for acute lymphoblastic leukaemia or non-B malignant non-Hodgkin lymphoma. All 90 patients had normal brain imaging before treatment. In these patients, brain imaging was performed after treatment completion and/or relapse and/or occurrence of neurological symptoms.

RESULTS

Of the 90 patients, 15 (16.7%) showed signs of MTX neurotoxicity on brain MRI, 9 (10%) were asymptomatic, and 6 (6.7%) showed signs of acute leukoencephalopathy. On the routine brain MRI performed at the end of treatment, all asymptomatic patients had classical MR findings of reversible MTX neurotoxicity, such as abnormal high-intensity areas localized in the deep periventricular white matter on T2-weighted images. In contrast, the six symptomatic patients had atypical brain MRI characterized by T2 high-intensity areas in the supratentorial cortex and subcortical white matter (n=6), cerebellar cortex and white matter (n=4), deep periventricular white matter (n=2) and thalamus (n=1). MR normalization occurred later than clinical recovery in these six patients.

CONCLUSIONS

In addition to mostly asymptomatic classical MTX neurotoxicity, MTX may induce severe but reversible unusual leukoencephalopathy. It is important to recognize this clinicoradiological presentation in the differential diagnosis of acute neurological deterioration in children treated with MTX.

Delayed neurotoxicity associated with therapy for children with acute lymphoblastic leukemia

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

Correlation of cerebrospinal fluid beta-glucuronidase activity with plasma methotrexate concentrations in leukemic children receiving high-dose methotrexate

BACKGROUND

The activity of lysosomal enzymes is increased in body fluids during inflammation, in which cellular malfunction and cellular death occurs. Because chemotherapy also causes cell malfunction and death, for identifying a neurologic effect, we studied the activity of beta-glucuronidase in the cerebrospinal fluid (CSF) of leukemic children during treatment.

PROCEDURE

The beta-glucuronidase activity in CSF was determined in 13 patients with B-precursor acute lymphoblastic leukemia (ALL) treated with the medium risk arm of ALL Berlin-Frankfurt-Munster (BFM) 95 protocol. Plasma methotrexate (MTX) levels were determined at 24 and 48 hr after the infusion of high-dose (5 g/m(2)/24 hr) MTX (MCA phase).

RESULTS

The mean (SD) beta-glucuronidase activity prior to the onset of chemotherapy was 19.9 (5.6) nmoles/4-methylumbelliferone/ml/hr. No significant changes in activity were noted during the phases of the protocol except of the MCA3. The activity was 24.4 (6.8) on MCA2, 28.4 (9.3) on MCA3, and 24.1 (9.5) on MCA4. The beta-glucuronidase activity was positively correlated with the plasma MTX levels at both 24 hr (r = 0.483, P = 0.006) and 48 hr (r = 0.676, P < 0.0001). No progressive changes were noted during the different phases of the protocol. The greatest beta-glucuronidase activity was measured in two patients with neurotoxicity.

CONCLUSIONS

The beta-glucuronidase activity is increased in the CSF of leukemic children receiving high-dose MTX and particularly in neurotoxicity. It is positively correlated with plasma MTX levels. No cumulative effect of the chemotherapy was observed. The increased beta-glucuronidase activity is most likely due to enzyme leakage through the cell membranes caused mainly by a toxic effect of MTX on the cells of the central nervous system (CNS).

Defining the appropriate dosage of folinic acid after high-dose methotrexate for childhood acute lymphatic leukemia that will prevent neurotoxicity without rescuing malignant cells in the central nervous system

Neurotoxicity after the administration of methotrexate continues to worry physicians. However, inadequate folinic acid rescue is often not considered as a cause of this complication. To clarify whether adequate folinic acid rescue prevents methotrexate-induced neurotoxicity without reducing the cure rate in childhood ALL, published evidence that supported or refuted this claim was investigated. A literature search was conducted and the authors of the relevant studies were contacted. The published data supported the contention that neurotoxicity can be prevented by adequate folinic acid rescue even after very high doses of methotrexate. The safe minimum dose of folinic acid can be defined in terms of the dose of methotrexate given; the time to start of rescue is probably less important. There was no evidence that higher doses of folinic acid, such as those used after methotrexate in the treatment of osteosarcoma, rescue leukemia cells. No change in cure rate was found in relation to changes in scheduling or clinically relevant doses of folinic acid rescue. The accumulation of folinic acid in the cerebrospinal fluid did not seem to be of clinical relevance. No studies indicate that doses of folinic acid after high-dose methotrexate administration interfere with the killing of leukemia cells, nor that delaying the start of rescue beyond a certain point increases the antileukemic effect; neurotoxicity will, however, be increased. Review of current protocols that use low-dose folinic acid rescue and are associated with neurotoxicity is highly recommended.

Recent publications in hematological oncology

In order to keep subscribers up-to-date with the latest developments in their field, John Wiley & Sons are providing a current awareness service in each issue of the journal. The bibliography contains newly published material in the field of hematological oncology. Each bibliography is divided into 14 sections: 1 Books, Reviews & Symposia; 2 General; Leukemias: 3 Lymphoblastic; 4 Myeloid & Myelodysplastic Syndromes; 5 Chronic; 6 Others; Lymphomas: 7 Hodgkin's; 8 Non-Hodgkin's; 9 Plasmacytomas/Multiple Myelomas; 10 Others; 11 Bone Marrow Transplantation; 12 Cytokines; 13 Diagnosis; 14 Cytogenetics. Within each section, articles are listed in alphabetical order with respect to author. If, in the preceding period, no publications are located relevant to any one of these headings, that section will be omitted.