Methotrexate-induced neurotoxicity and leukoencephalopathy in childhood acute lymphoblastic leukemia

Clinical Characteristics and Outcome of Children With Relapsed Medulloblastoma: A Retrospective Study at a Single Center in China

Relapsed medulloblastoma (MB) has a dire prognosis, and chemotherapy remains the main therapeutic option. We retrospectively analyzed the clinical characteristics and survival rates of 60 Chinese children with relapsed MB. The patients received 11 cycles of chemotherapy in sequence, followed by 12 cycles of oral temozolomide and etoposide. Thirty patients were simultaneously administered intrathecal methotrexate (IT-MTX). The Kaplan-Meier method was used to determine survival rates; the patients' median survival time after relapse was 2.8 years, 5-year progression-free survival (PFS) and overall survival (OS) rates were 26.7%±5.7% and 31.6%±6.9%, respectively. There was no significant difference between these rates according to histology or molecular subgroup. Tumor cells were detected in the cerebrospinal fluid of over 40% of patients; such patients had significantly shorter OS and PFS rates. Patients who received IT-MTX showed significantly longer survival than those who did not (3.73 vs. 2.06 y, respectively, P=0.000); the corresponding 5-year PFS and OS rates were 43.3%±9.0% versus 10.0%±5.5% and 49.5%±11.1% versus 14.6%±6.9%, respectively (P=0.000). In addition, tumor cell-positive cerebrospinal fluid and IT-MTX use significantly influenced PFS and OS in relapsed patients. Taken together, our data show that IT-MTX improves the survival of patients with relapsed MB.

The effect of intravenous hydration strategy on plasma methotrexate clearance during intravenous high-dose methotrexate administration in pediatric oncology patients

Background

High-dose methotrexate (HD-MTX) is widely used as a standard chemotherapeutic agent in pediatric cancers. Most research studies have confirmed the therapeutic efficacy of HD-MTX; however, strategies to prevent side effects vary among institutions, especially in developing countries, with limited monitoring of plasma methotrexate level.

Objective

To evaluate the effect of intravenous hydration during HD-MTX administration on plasma methotrexate clearance in pediatric oncology patients.

Materials and methods

This study retrospectively reviewed 165 courses of HD-MTX administered to children with acute lymphoblastic leukemia (ALL), non-Hodgkin’s lymphoma (NHL), or osteosarcoma. Demographic data of patients were collected. Adverse complications related to HD-MTX and 72-hour plasma methotrexate level were analyzed between patients receiving intravenous hydration ≥3,000 mL/m²/day and those receiving hydration <3,000 mL/m²/day.

Results

Among 56 HD-MTX (1.5 g/m²) courses in ALL, delayed methotrexate clearance was only found in one course administered with hydration <3,000 mL/m²/day. However, no correlation was observed between adverse complications and methotrexate levels. Of 34 HD-MTX (1.5–3 g/m²) courses in NHL, no significant correlation was observed between methotrexate levels and intravenous hydration. However, increased adverse complications were found in the course with delayed methotrexate clearance. Interestingly, among 75 HD-MTX (10–12 g/m²) courses in osteosarcoma, normal methotrexate clearance was successfully achieved in all courses administered with hydration ≥3,000 mL/m²/day compared with those administered with hydration <3,000 mL/m²/day (P=0.007). Furthermore, the courses administered with hydration <3,000 mL/m²/day and had delayed methotrexate clearance were more likely to develop adverse complications.

Conclusion

Intravenous hydration of ≥3,000 mL/m²/day during HD-MTX administration is essentially required in osteosarcoma and can be considered as optional in ALL with HD-MTX <1.5 g/m², especially in developing countries with limited monitoring of plasma methotrexate level.

Disparities in Neurotoxicity Risk and Outcomes among Pediatric Acute Lymphoblastic Leukemia Patients

Purpose: Methotrexate chemotherapy can be associated with neurologic complications during therapy and long-term neurologic deficits. This study evaluated demographic and clinical factors associated with incidence of methotrexate neurotoxicity and described the impact of neurotoxicity on acute lymphoblastic leukemia (ALL) therapy in pediatric patients.Experimental Design: Patients were enrolled between 2012 and 2017 from three pediatric cancer treatment centers in the United States. Medical records for suspected cases of methotrexate neurotoxicity, defined as an acute neurologic event following methotrexate therapy, were reviewed. Cox proportional hazards models were used to estimate the association between race/ethnicity and methotrexate neurotoxicity. Multivariable linear regression models compared treatment outcomes between patients with and without methotrexate neurotoxicity.Results: Of the 280 newly diagnosed patients enrolled, 39 patients (13.9%) experienced methotrexate neurotoxicity. Compared with non-Hispanic whites, Hispanic patients experienced the greatest risk of methotrexate neurotoxicity (adjusted HR, 2.43; 95% CI, 1.06-5.58) after accounting for sex, age at diagnosis, BMI Z-score at diagnosis, and ALL risk stratification. Patients who experienced a neurotoxic event received an average of 2.25 fewer doses of intrathecal methotrexate. Six of the 39 cases of neurotoxicity (15.4%) experienced relapse during the study period, compared with 13 of the 241 (2.1%) patients without neurotoxicity (P = 0.0038).Conclusions: Hispanic ethnicity was associated with increased risk of methotrexate neurotoxicity, which was associated with treatment modifications and relapse. Understanding the mechanism and predictors of methotrexate neurotoxicity is important to improving treatment outcomes in pediatric ALL. Clin Cancer Res; 24(20); 5012-7. ©2018 AACR.

The Impact of Persistent Leukoencephalopathy on Brain White Matter Microstructure in Long-Term Survivors of Acute Lymphoblastic Leukemia Treated with Chemotherapy Only

BACKGROUND AND PURPOSE

Survivors of acute lymphoblastic leukemia are at risk for neurocognitive deficits and leukoencephalopathy. We performed a longitudinal assessment of leukoencephalopathy and its associations with long-term brain microstructural white matter integrity and neurocognitive outcomes in survivors of childhood acute lymphoblastic leukemia treated on a modern chemotherapy-only protocol.

MATERIALS AND METHODS

One hundred seventy-three survivors of acute lymphoblastic leukemia (49% female), treated on a chemotherapy-only protocol, underwent brain MR imaging during active therapy and repeat imaging and neurocognitive testing at follow-up (median, 13.5 years of age; interquartile range, 10.7-17.6 years; median time since diagnosis, 7.5 years; interquartile range, 6.3-9.1 years). Persistence of leukoencephalopathy was examined in relation to demographic and treatment data and to brain DTI in major fiber tracts and neurocognitive testing at follow-up.

RESULTS

Leukoencephalopathy was found in 52 of 173 long-term survivors (30.0%) and persisted in 41 of 52 (78.8%) who developed it during therapy. DTI parameters were associated with leukoencephalopathy in multiple brain regions, including the corona radiata (fractional anisotropy, P = .001; mean diffusivity, P < .001), superior longitudinal fasciculi (fractional anisotropy, P = .02; mean diffusivity, P < .001), and superior fronto-occipital fasciculi (fractional anisotropy, P = .006; mean diffusivity, P < .001). Mean diffusivity was associated with neurocognitive impairment including in the genu of the corpus callosum (P = .04), corona radiata (P = .02), and superior fronto-occipital fasciculi (P = .02).

CONCLUSIONS

Leukoencephalopathy during active therapy and neurocognitive impairment at long-term follow-up are associated with microstructural white matter integrity. DTI may be more sensitive than standard MR imaging for detection of clinically consequential white matter abnormalities in childhood acute lymphoblastic leukemia survivors treated with chemotherapy and in children undergoing treatment.

Characteristics of methotrexate-induced stroke-like neurotoxicity

Intrathecal administration of methotrexate (IT-MTX) can lead to neurotoxicity. MTX-induced neurotoxicity occasionally manifests with a stroke-like presentation that is difficult to distinguish from genuine stroke. We retrospectively reviewed records of nine patients with leukemia or lymphoma and episodes of stroke-like presentation at our institute between 2010 and 2015 for whom magnetic resonance imaging (MRI) data were available. Coagulation test results were compared between the two diagnostic groups. Four patients were diagnosed with MTX-induced stroke-like neurotoxicity. The first neurological event occurred 10-13 days after the fourth or later IT-MTX treatment. All four patients had hemiparalysis, two exhibited disturbed consciousness and three presented with speech disorders. Fibrin/fibrinogen degradation products (FDP) and D-dimer values were within normal ranges. MRI revealed bilateral lesions with restricted diffusion in all four cases. Neurological symptoms fluctuated and resolved within 5 days, and IT-MTX was subsequently re-initiated in all four cases. One patient developed transient hemiparalysis after a subsequent IT-MTX treatment, but this did not recur thereafter. Bilateral lesions on MRI and normal coagulation are indicative of MTX-induced stroke-like neurotoxicity. Continuation of IT-MTX after these events is generally feasible, but adverse event risk should be carefully weighed against anti-tumor benefits.

Utility and Safety of Intrathecal Methotrexate Treatment in Severe Anti-N-methyl-D-aspartate Receptor Encephalitis: A Pilot Study

Background:

Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is a treatable autoimmune neurologic syndrome that occurs with or without tumor association. However, some severe cases are refractory to systemic immunotherapy. This pilot study aimed to evaluate the utility and safety of intrathecal methotrexate injection for severe patients with anti-NMDAR encephalitis who did not respond to first-line immunotherapy.

Methods:

Intrathecal injections with methotrexate and dexamethasone were performed weekly in four legible patients within consecutive 4 weeks. Cerebrospinal fluid (CSF) was collected at baseline and each time of intrathecal injection for identification of anti-NMDAR antibody titers.

Results:

Significant clinical improvement was observed in three patients associated with a stepwise decrease of CSF anti-NMDAR antibody titers (maximum: 1/320 to minimum: 1/10). After 2 months of follow-up, they were able to follow simple commands and had appropriate interactions with people (modified Rankin scale [mRS] of 0–2). At 12 months of follow-up, they all had returned to most activities of daily life (mRS of 0), and no relapses were reported. One patient showed no clinical improvement and died of neurologic complications.

Conclusions:

Intrathecal treatment may be a potentially useful supplementary therapy in severely affected patients with anti-NMDAR encephalitis. Further large cohort study and animal experiment may help us elaborate the utility of intrathecal injection of methotrexate and its mechanism of action.

Neurological Complications of the Treatment of Pediatric Neoplastic Disorders

Neurological complications resulting from childhood cancer treatments are common. Treatment for childhood neoplastic disorders is often multimodal and may include procedures, cranial irradiation, chemotherapy, transplant, and immunotherapy, each of which carries distinct neurological risks. Procedures, such as lumbar punctures, are commonly used in this population for diagnostic purposes as well as intrathecal medication administration. Surgery is associated with an array of potential neurological complications, with posterior fossa syndrome being a common cause of morbidity in pediatric brain tumor patients after neurosurgical resection. Cranial irradiation can cause late neurological sequelae such as stroke, cerebral vasculopathy, secondary malignancy, and cognitive dysfunction. Neurotoxic effects of chemotherapeutic agents are common and include neuropathy, coagulopathy causing stroke or cerebral sinovenous thrombosis, encephalopathy, seizures, cerebellar dysfunction, myelopathy, and neuropsychologic difficulties. Hematopoietic stem cell transplant has a high risk of neurological complications including central nervous system infection, seizures, and stroke. Immunotherapies, including chimeric antigen receptor-modified T-cells (CAR T-cells) and immune checkpoint inhibitors, are emerging as potentially effective strategies to treat some types of childhood cancer, but may carry with them substantial neurotoxicity which is just beginning to be recognized and studied. With evolving treatment protocols, childhood cancer survivorship is increasing, and the role of the neurologist in managing both the acute and chronic neurological consequences of treatment is becoming more important. Prevention, early recognition, and treatment of therapy-associated neurotoxicity are imperative to ensuring children can remain on the most effective therapeutic regimens and to improve the neurological function and quality of life of childhood cancer survivors.

The Use of Ommaya Reservoirs to Deliver Central Nervous System-Directed Chemotherapy in Childhood Acute Lymphoblastic Leukaemia

Prophylactic eradication of central nervous system (CNS) leukaemia is the current standard of care in treating childhood acute lymphoblastic leukaemia (ALL). This is conventionally achieved through regular lumbar punctures with intrathecal injections of methotrexate into the cerebrospinal fluid (CSF). Ommaya reservoirs are subcutaneous implantable devices that provide a secure route of drug delivery into the CSF via an intraventricular catheter. They are an important alternative in cases where intrathecal injection via lumbar puncture is difficult. Among UK Paediatric Principal Treatment Centres for ALL we found considerable variation in methotrexate dosing when using an Ommaya reservoir. We review the current safety and theoretical considerations when using Ommaya reservoirs and evidence for methotrexate dose adjustments via this route. We conclude by summarising the pragmatic consensus decision to use 50% of the conventional intrathecal dose of methotrexate when it is administered via Ommaya reservoir in front-line ALL therapy.

Association of Cerebrospinal Fluid Biomarkers of Central Nervous System Injury With Neurocognitive and Brain Imaging Outcomes in Children Receiving Chemotherapy for Acute Lymphoblastic Leukemia

Importance

Little is known about treatment-related neurotoxic mechanisms in children with acute lymphoblastic leukemia (ALL) treated with chemotherapy only.

Objective

To examine concentration of cerebrospinal fluid (CSF) biomarkers of brain injury at ALL diagnosis and during cancer therapy and to evaluate associations with long-term neurocognitive and neuroimaging outcomes and relevant genetic polymorphisms.

Design, Setting, and Participants

This prospective cohort study included 235 patients with ALL who received a chemotherapy-only protocol. Patients provided CSF samples after diagnosis and throughout treatment. At 5 or more years after the diagnosis, 138 (69.7%) of 198 eligible survivors participated in long-term follow-up assessments. Children were treated from June 1, 2000, through October 31, 2010. Follow-up was completed on October 21, 2014, and data were analyzed from August 1, 2015, through September 30, 2016.

Exposures

Plasma concentration of high-dose intravenous methotrexate sodium and number of triple intrathecal chemotherapy injections.

Main Outcomes and Measures

The CSF samples were assayed at 5 points from diagnosis to reinduction for biomarkers of myelin degradation (myelin basic protein [MBP]), neuronal damage (nerve growth factor [NGF] and total and phosphorylated tau protein), astrogliosis (glial fibrillary acidic protein [GFAP]), and neuroinflammation (chitotriosidase). DNA was genotyped for polymorphisms in drug metabolism, oxidative stress, and neurodevelopment. Leukoencephalopathy was evaluated by brain imaging. At 5 or more years after the diagnosis, survivors completed neurocognitive testing and brain imaging of white matter integrity.

Results

Among the 235 patients with CSF samples (120 boys [51.1%] and 115 girls [48.9%]; mean [SD] age at diagnosis, 6.8 [4.7] years), MBP and GFAP levels were elevated at baseline and through consolidation. The number of intrathecal injections was positively correlated with NGF level increase at consolidation (r = 0.19; P = .005). Increases in GFAP (risk ratio [RR], 1.23; 95% CI, 1.09-1.40), MBP (RR, 1.06; 95% CI, 1.01-1.11), and total tau (RR, 1.76; 95% CI, 1.11-2.78) levels were associated with a higher risk for leukoencephalopathy and higher apparent diffusion coefficient in frontal lobe white matter 5 years after diagnosis (standardized estimate, 0.05; P < .001). Increase in total tau at consolidation was associated with worse attention (omissions z score estimate, -0.20; P = .04).

Conclusions and Relevance

Glial injury may be present at diagnosis of ALL. Neuronal injury was associated with intrathecal chemotherapy. The CSF biomarkers may be useful in identifying individuals at risk for worse neurologic outcomes, particularly those with genetic susceptibility to poor brain function.

Neurodevelopmental consequences of pediatric cancer and its treatment: applying an early adversity framework to understanding cognitive, behavioral, and emotional outcomes

Today, children are surviving pediatric cancer at unprecedented rates, making it one of modern medicine's true success stories. However, we are increasingly becoming aware of several deleterious effects of cancer and the subsequent "cure" that extend beyond physical sequelae. Indeed, survivors of childhood cancer commonly report cognitive, emotional, and psychological difficulties, including attentional difficulties, anxiety, and posttraumatic stress symptoms (PTSS). Cognitive late- and long-term effects have been largely attributed to neurotoxic effects of cancer treatments (e.g., chemotherapy, cranial irradiation, surgery) on brain development. The role of childhood adversity in pediatric cancer - namely, the presence of a life-threatening disease and endurance of invasive medical procedures - has been largely ignored in the existing neuroscientific literature, despite compelling research by our group and others showing that exposure to more commonly studied adverse childhood experiences (i.e., domestic and community violence, physical, sexual, and emotional abuse) strongly imprints on neural development. While these adverse childhood experiences are different in many ways from the experience of childhood cancer (e.g., context, nature, source), they do share a common element of exposure to threat (i.e., threat to life or physical integrity). Therefore, we argue that the double hit of early threat and cancer treatments likely alters neural development, and ultimately, cognitive, behavioral, and emotional outcomes. In this paper, we (1) review the existing neuroimaging research on child, adolescent, and adult survivors of childhood cancer, (2) summarize gaps in our current understanding, (3) propose a novel neurobiological framework that characterizes childhood cancer as a type of childhood adversity, particularly a form of early threat, focusing on development of the hippocampus and the salience and emotion network (SEN), and (4) outline future directions for research.

Effects of leucovorin (folinic acid) in the methotrexate-treated rat brain

Folinic acid (FA) is generally administered to patients with CNS tumors in order to treat severe neurological disorders caused by methotrexate (MTX); therefore, we herein examined the effects of the co-administration of FA on MTX concentrations in the rat brain and cerebrospinal fluid (CSF) as well as the pharmacokinetics of MTX. MTX was intravenously or intrathecally administered to rats with or without FA. MTX concentrations were assessed by HPLC. No significant differences were observed in pharmacokinetic parameters, including k_el, V_d, AUC, Cl_tot and t_1/2, between the FA-treated and non-treated groups. MTX concentrations were not significantly different in the brain or CSF 6 hr after the intrathecal administration of MTX. However, compare to intravenous administration of MTX, intravenous administration of both FA and MTX significantly decreased MTX concentrations in the brains and CSF. These results suggest that FA inhibits the influx of MTX into the brain and CSF, possibly by competing with folate carriers, but has no effect on its efflux from these regions. Therefore, FA may be administered to CNS tumor patients receiving intrathecal MTX therapy in order to treat the adverse effects of MTX without affecting its concentrations in the brain and CSF.

Systematic review of pharmacogenomics and adverse drug reactions in paediatric oncology patients

Many paediatric patients with cancer experience significant chemotherapy side effects. Predisposition to drug reactions is governed by single nucleotide polymorphisms (SNPs). We performed a systematic review of the literature from 2006 through 2016. Outcomes of interest included patient characteristics, cancer type drug of interest, genes investigated, toxicity identified and genetic polymorphisms implicated. The primary toxicities studied were neurotoxicity cardiotoxicity, osteonecrosis, and thromboembolism and hypersensitivity reactions. The retrieved studies were grouped according to toxicity reported and SNP associations. This review highlights the discoveries to date in pharmacogenomics and paediatric oncology along with highlighting some of the important limitations in the area.

Behavioral symptoms and psychiatric disorders in child and adolescent long-term survivors of childhood acute lymphoblastic leukemia treated with chemotherapy only

BACKGROUND

Prevalence of emotional, behavioral, and psychiatric outcomes in child and adolescent survivors of childhood acute lymphoblastic leukemia treated on a chemotherapy-only protocol were not well defined.

METHODS

Self- and parent-reported emotional and behavioral symptoms were assessed for 161 survivors of childhood acute lymphoblastic leukemia (51.0% female; mean [SD] age 12.1[2.6] years; 7.5[1.6] years post-diagnosis). Age- and sex-adjusted scores were calculated for standardized measures and compared with 90th percentile of norms. Frequencies of survivor psychiatric disorders from structured diagnostic interviews with parents were compared with the general population. Parent emotional distress and post-traumatic stress symptoms were assessed. Associations between child symptoms/disorders and parent distress were examined with log-binomial models, adjusting for highest parent education.

RESULTS

Compared with population expectations (10%), more survivors self-reported symptoms of inattention (27.9; 95% CI, 21.0%-35.7%), hyperactivity/impulsivity (26.0%; CI, 19.2%-33.6%), and oppositional-defiant behavior (20.1%; CI, 14.1%-27.3%). Parents reported survivors with more symptoms of inattention (23.6%; CI, 17.2%-31.0%), higher frequencies of obsessive-compulsive disorder (10.3% vs 2%) and oppositional defiant disorder (16.0% vs 9.5%), but not attention-deficit/hyperactivity disorder (7.1% vs 7.8%) or generalized anxiety disorder (3.2% vs 4.1%), compared with national norms. Parent-report of child anxiety disorders was associated with parent self-reported emotional distress but not survivor self-report of anxiety.

CONCLUSION

A significant minority of survivors have long-term psychiatric morbidity, multi-informant assessment is important to understand these symptom profiles and to inform selection of appropriate interventions. Interventions targeting inattention and oppositional behavior in children and emotional distress in parents are warranted in families with survivors who display behavioral problems.

Evolution of neurocognitive function in long-term survivors of childhood acute lymphoblastic leukemia treated with chemotherapy only

PURPOSE

The purpose of this study was to determine the evolution of neurocognitive problems from therapy completion to long-term follow-up in survivors of childhood acute lymphoblastic leukemia treated with chemotherapy only.

METHODS

We evaluated whether attention problems observed at therapy completion evolve into long-term executive dysfunction in 158 survivors treated on a single institution protocol. Treatment data (high-dose intravenous methotrexate exposure [serum concentration] and triple intrathecal chemotherapy injections) were collected. Parent report of behavior and direct cognitive testing of survivors was conducted at end of therapy, and survivors completed neurocognitive testing when > 5 years post-diagnosis.

RESULTS

At the end of chemotherapy, survivors (52% female; mean age 9.2 years) demonstrated higher frequency of impairment in sustained attention (38%) and parent-reported inattention (20%) compared to population expectations (10%). At long-term follow-up, survivors (mean age 13.7 years; 7.6 years post-diagnosis) demonstrated higher impairment in executive function (flexibility 24%, fluency 21%), sustained attention (15%), and processing speed (15%). Sustained attention improved from end of therapy to long-term follow-up (p < 0.001). Higher methotrexate AUC and greater number of intrathecal injections were associated with attention problems (p = 0.009, p = 0.002, respectively) at the end of chemotherapy and executive function (p < 0.001, p = 0.02, respectively) problems at long-term follow-up. Attention problems at the end of therapy were not associated with executive function problems at long-term follow-up (p's > 0.05). The direct effect of chemotherapy exposure predicted outcomes at both time points.

CONCLUSIONS AND IMPLICATIONS FOR CANCER SURVIVORS

Survivors should be monitored for neurocognitive problems well into long-term survivorship, regardless of whether they show attention problems at the end of therapy. Treatment exposures are the best predictor of long-term complications.

BCL6 modulation of acute lymphoblastic leukemia response to chemotherapy

The bone marrow niche has a significant impact on acute lymphoblastic leukemia (ALL) cell phenotype. Of clinical relevance is the frequency with which quiescent leukemic cells, in this niche, survive treatment and contribute to relapse. This study suggests that marrow microenvironment regulation of BCL6 in ALL is one factor that may be involved in the transition between proliferative and quiescent states of ALL cells. Utilizing ALL cell lines, and primary patient tumor cells we observed that tumor cell BCL6 protein abundance is decreased in the presence of primary human bone marrow stromal cells (BMSC) and osteoblasts (HOB). Chemical inhibition, or shRNA knockdown, of BCL6 in ALL cells resulted in diminished ALL proliferation. As many chemotherapy regimens require tumor cell proliferation for optimal efficacy, we investigated the consequences of constitutive BCL6 expression in leukemic cells during co-culture with BMSC or HOB. Forced chronic expression of BCL6 during co-culture with BMSC or HOB sensitized the tumor to chemotherapy induced cell death. Combination treatment of caffeine, which increases BCL6 expression in ALL cells, with chemotherapy extended the event free survival of mice. These data suggest that BCL6 is one factor, modulated by microenvironment derived cues that may contribute to regulation of ALL therapeutic response.

Changes in cognition and dendritic complexity following intrathecal methotrexate and cytarabine treatment in a juvenile murine model

Acute lymphoblastic leukemia (ALL) is the most prevalent childhood cancer and accounts for 26.8% of cancer diagnoses among children, worldwide-approximately 3000 children each year. While advancements in treating ALL have led to a remission rate of more than 90%, many survivors experience adverse neurocognitive and/or neurobehavioral effects as a result of intrathecal chemotherapy. Methotrexate (MTX) is commonly administered with cytosine arabinoside (AraC, cytarabine) during intrathecal chemotherapy for ALL. To date, few studies exist that test the cognitive effects of intrathecal injections of MTX/AraC on juvenile populations. The purpose of our study was to investigate the combined effects of MTX/AraC on cognition and dendritic structure in the hippocampus in juvenile male mice. Twenty, 21-day-old male C57BL/6 mice were used in this study; 10 mice received intrathecal MTX/AraC treatment, and 10 were given intrathecal saline injections. Five weeks after injections, we tested the animals' hippocampus-dependent cognitive performance in the Morris water maze. After the first day of hidden-platform training, we observed that the mice that received MTX/AraC treatment showed signs of significant impairment in spatial memory retention. MTX/AraC treatment significantly compromised the dendritic architecture and reduced mushroom spine density in the dorsal ganglion (DG), CA1, and CA3 areas of the hippocampus. The present data provided evidence that MTX/AraC compromised the dendritic architecture and impaired hippocampal dependent cognition. This could provide insight into chemotherapy-induced cognitive decline in juvenile patients treated for ALL.

Crisis management in the treatment of childhood acute lymphoblastic leukemia: putting right what can go wrong (emergency complications of disease and treatment)

The improvement in overall survival in children with acute lymphoblastic leukemia (ALL) over the last 5 decades has been considerable, with around 90% now surviving long term. The risk of relapse has been reduced to such an extent that the risk of treatment-related mortality is now approaching that of mortality caused by relapse. Toxicities may also lead to the suboptimal delivery of chemotherapy (treatment delays, dose reductions, dose omissions), potentially increasing relapse risk, and short- and long-term morbidity, adding to the "burden of therapy" in an increasing number of survivors. Thus, the need to reduce toxicity in pediatric ALL is becoming increasingly important. This work focuses on the risk factors, pathogenesis, clinical features, and emergency management of the life-threatening complications of ALL at presentation and during subsequent chemotherapy, including leucostasis, tumor lysis syndrome, infection, methotrexate encephalopathy, thrombosis, and pancreatitis. Potential strategies to abrogate these toxicities in the future are also discussed.

[Acute methotrexate-related neurotoxicity and pseudo-stroke syndrome]

Treatment of acute lymphoblastic leukemia requires high-dose systemic and/or intrathecal methotrexate to prevent and/or treat central nervous system disorders. Acute neurotoxicity of methotrexate, of unknown etiopathogenesis, is characterized by the polymorphism of clinical manifestations, responsible for a potentially harmful diagnostic delay in these immunosuppressed patients. We describe five episodes of transient acute leukoencephalopathy mimicking a stroke, reported in the literature as "pseudo-stroke syndrome". Neurologic symptoms occurred 3-10 days after IV or IT methotrexate and manifested as aphasia and alternating sensorimotor deficit. The fluctuating symptomatology regressed completely within a few days. Brain MRI, which is essential for diagnosis, demonstrated early white matter diffusion restriction in the affected cerebral area. These anomalies disappeared in one week, while hyperintense T2 FLAIR signals developed in the corresponding brain areas. The long-term progression of these pseudo-stroke patients was favorable, without any therapeutic modification. Nevertheless, the involvement of transient acute leukoencephalopathy episodes in the progressive onset of neuro-cognitive disorders is discussed.

Methotrexate-induced leukoencephalopathy presenting as stroke in the emergency department

Methotrexate-induced leukoencephalopathy is to be considered as a potential etiology in any patient presenting with stroke-like symptoms after receiving methotrexate. One of our cases suggests that the method of administration of the methotrexate can be IV or intrathecal and still results in leukoencephalopathy.

EEG with extreme delta brush in young female with methotrexate neurotoxicity supports NMDA receptor involvement

Sub-acute neurotoxicity is a well-known complication to high-dose and intrathecal methotrexate (MTX) treatment of children with leukemia. Symptoms can be treated safely by dextromethorphan, a non-competitive antagonist to N-methyl-D-aspartic acid receptor (NMDAR). In a female with subacute MTX neurotoxicity, we observed an electroencephalographic (EEG) with extreme delta brush. Extreme delta brush is an EEG pattern previously described in patients with NMDAR autoimmune encephalitis. The observations suggest that the mechanism of this neurotoxicity may be mediated by the NMDAR. Furthermore, extreme EEG delta brush should suggest a diagnosis of MTX associated subacute neurotoxicity.

Health-related quality of life of children on treatment for acute lymphoblastic leukemia: A systematic review

Children with acute lymphoblastic leukemia (ALL) undergo intense anticancer treatment. We systematically reviewed 22 studies evaluating 2,073 ALL patients' health-related quality of life (HRQL) and its clinical/demographic correlates during treatment. Overall HRQL was significantly reduced on treatment. Despite HRQL improvements over time, longitudinal studies reported a proportion of children continued to experience reduced HRQL after treatment completion. We found inconsistent associations between clinical/demographic factors and HRQL outcomes. Tentative evidence emerged for worse HRQL being associated with intensive phases of chemotherapy, corticosteroid therapy, experiencing greater toxicity, older age, and female sex. Longitudinal studies are needed to identify children at-risk of reduced HRQL.

A PET/MR Imaging Approach for the Integrated Assessment of Chemotherapy-induced Brain, Heart, and Bone Injuries in Pediatric Cancer Survivors: A Pilot Study

Purpose To develop a positron emission tomography (PET)/magnetic resonance (MR) imaging protocol for evaluation of the brain, heart, and joints of pediatric cancer survivors for chemotherapy-induced injuries in one session. Materials and Methods Three teams of experts in neuroimaging, cardiac imaging, and bone imaging were tasked to develop a 20-30-minute PET/MR imaging protocol for detection of chemotherapy-induced tissue injuries of the brain, heart, and bone. In an institutional review board-approved, HIPAA-compliant, prospective study from April to July 2016, 10 pediatric cancer survivors who completed chemotherapy underwent imaging of the brain, heart, and bone with a 3-T PET/MR imager. Cumulative chemotherapy doses and clinical symptoms were correlated with the severity of MR imaging abnormalities by using linear regression analyses. MR imaging measures of brain perfusion and metabolism were compared among eight patients who were treated with methotrexate and eight untreated age-matched control subjects by using Wilcoxon rank-sum tests. Results Combined brain, heart, and bone examinations were completed within 90 minutes. Eight of 10 cancer survivors had abnormal findings on brain, heart, and bone images, including six patients with and two patients without clinical symptoms. Cumulative chemotherapy doses correlated significantly with MR imaging measures of left ventricular ejection fraction and end-systolic volume, but not with the severity of brain or bone abnormalities. Methotrexate-treated cancer survivors had significantly lower cerebral blood flow and metabolic activity in key brain areas compared with control subjects. Conclusion The feasibility of a single examination for assessment of chemotherapy-induced injuries of the brain, heart, and joints was shown. Earlier detection of tissue injuries may enable initiation of timely interventions and help to preserve long-term health of pediatric cancer survivors. ^© RSNA, 2017 Online supplemental material is available for this article.

Malignant Cerebellar Edema Subsequent to Accidental Prescription Opioid Intoxication in Children

We present two recent cases of toddlers who developed malignant cerebellar edema subsequent to accidental ingestion of prescription opioids. Both children presented acute neurological decline, hydrocephalus, and tonsillar herniation requiring emergent ventricular drain placement, suboccipital craniectomy, and partial cerebellectomy. Together with several other reports, these cases suggest the existence of an uncommon yet severe syndrome of acute opioid-induced malignant cerebellar edema. We hypothesize that the condition results from a combination of primary opioid receptor-mediated changes in neuronal metabolism that are exacerbated by secondary hypoxic insult. If recognized promptly, this syndrome can be treated with emergent neurosurgical intervention with good clinical outcomes. These cases also illustrate the unintended consequences and innocent victims of the spiraling prescription opioid epidemic, which will likely increase in prevalence. Recognition of this syndrome by clinicians is thus critical.

Neurocognitive Functioning of Children Treated for High-Risk B-Acute Lymphoblastic Leukemia Randomly Assigned to Different Methotrexate and Corticosteroid Treatment Strategies: A Report From the Children's Oncology Group

Purpose Survivors of childhood acute lymphoblastic leukemia (ALL) are at risk for neurocognitive deficits that are associated with treatment, individual, and environmental factors. This study examined the impact of different methotrexate (MTX) and corticosteroid treatment strategies on neurocognitive functioning in children with high-risk B-lineage ALL. Methods Participants were randomly assigned to receive high-dose MTX with leucovorin rescue or escalating dose MTX with PEG asparaginase without leucovorin rescue. Patients were also randomly assigned to corticosteroid therapy that included either dexamethasone or prednisone. A neurocognitive evaluation of intellectual functioning (IQ), working memory, and processing speed (PS) was conducted 8 to 24 months after treatment completion (n = 192). Results The method of MTX delivery and corticosteroid assignment were unrelated to differences in neurocognitive outcomes after controlling for ethnicity, race, age, gender, insurance status, and time off treatment; however, survivors who were age < 10 years at diagnosis (n = 89) had significantly lower estimated IQ ( P < .001) and PS scores ( P = .02) compared with participants age ≥ 10 years. In addition, participants who were covered by US public health insurance had estimated IQs that were significantly lower ( P < .001) than those with US private or military insurance. Conclusion Children with high-risk B-lineage ALL who were age < 10 years at diagnosis are at risk for deficits in IQ and PS in the absence of cranial radiation, regardless of MTX delivery or corticosteroid type. These data may serve as a basis for developing screening protocols to identify children who are at high risk for deficits so that early intervention can be initiated to mitigate the impact of therapy on neurocognitive outcomes.

[Adverse effects of high-dose methotrexate therapy]

OBJECTIVE

To investigate the adverse effects of high-dose methotrexate (HDMTX) therapy, and to provide a theoretical basis for optimizing clinical treatment.

METHODS

A retrospective analysis was performed for the clinical data of 120 children with acute lymphoblastic leukemia or non-Hodgkin lymphoma who underwent 601 times of HDMTX therapy. The adverse effects of various systems were analyzed according to the WHO criteria for the classification of adverse effects of anticancer drugs.

RESULTS

Almost all the children experienced bone marrow suppression, and 93.3% had granulocytopenia. The most common adverse effects in the digestive system and urinary system were elevated glutamic-pyruvic transaminase (60.4%) and proteinuria (9.2%) respectively. For skin symptoms, skin erythema had the highest incidence rate (7.2%). The adverse effects in the nervous system (hyperpathia, numbness of extremities, or headache) were only observed in 7 cases. Serious adverse effects were only seen in the blood system and digestive system. Compared with the 3 g/m² methotrexate (MTX) group, the 5 g/m² HDMTX group had a significantly higher 24-hour plasma MTX concentration, significant reductions in hemoglobin and platelet count, and significantly higher incidence rates of oral mucositis, proteinuria, and skin symptoms (P<0.05).

CONCLUSIONS

Serious adverse effects of HDMTX therapy mainly involve the blood system and digestive system, and the adverse effects such as bone marrow suppression, oral mucositis, proteinuria, and skin symptoms occur in a dose-dependent manner.

[Adverse effects of high-dose methotrexate therapy]

OBJECTIVE

To investigate the adverse effects of high-dose methotrexate (HDMTX) therapy, and to provide a theoretical basis for optimizing clinical treatment.

METHODS

A retrospective analysis was performed for the clinical data of 120 children with acute lymphoblastic leukemia or non-Hodgkin lymphoma who underwent 601 times of HDMTX therapy. The adverse effects of various systems were analyzed according to the WHO criteria for the classification of adverse effects of anticancer drugs.

RESULTS

Almost all the children experienced bone marrow suppression, and 93.3% had granulocytopenia. The most common adverse effects in the digestive system and urinary system were elevated glutamic-pyruvic transaminase (60.4%) and proteinuria (9.2%) respectively. For skin symptoms, skin erythema had the highest incidence rate (7.2%). The adverse effects in the nervous system (hyperpathia, numbness of extremities, or headache) were only observed in 7 cases. Serious adverse effects were only seen in the blood system and digestive system. Compared with the 3 g/m2 methotrexate (MTX) group, the 5 g/m2 HDMTX group had a significantly higher 24-hour plasma MTX concentration, significant reductions in hemoglobin and platelet count, and significantly higher incidence rates of oral mucositis, proteinuria, and skin symptoms (P<0.05).

CONCLUSIONS

Serious adverse effects of HDMTX therapy mainly involve the blood system and digestive system, and the adverse effects such as bone marrow suppression, oral mucositis, proteinuria, and skin symptoms occur in a dose-dependent manner.

The PETALE study: Late adverse effects and biomarkers in childhood acute lymphoblastic leukemia survivors

BACKGROUND

Childhood cancer survivorship issues represent an established public health challenge. Most late adverse effects (LAEs) have been demonstrated to be time and treatment dependent. The PETALE study is a multidisciplinary research project aiming to comprehensively characterize LAEs and identify associated predictive biomarkers in childhood acute lymphoblastic leukemia (cALL) survivors.

METHODS

cALL survivors treated at Sainte-Justine University Health Center with Dana-Farber Cancer Institution-ALL protocols 87-01 through 2005-01 were eligible. During Phase I of the study, the participants underwent comprehensive clinical, biologic, and psychosocial investigation targeting metabolic syndrome, cardiotoxicity, bone morbidity, neurocognitive problems, and quality of life issues. Whole-exome sequencing was performed for all participants. Subjects identified with an extreme phenotype during Phase I were recalled for additional testing (Phase II).

RESULTS

Phase I included 246 survivors (recall rate 71.9%). Of those, 85 participants completed Phase II (recall rate 88.5%). Survivors agreeing to participate in Phase I (n = 251) were similar to those who refused (n = 31) in terms of relapse risk profile, radiotherapy exposure, and age at the time of study. Participants, however, tended to be slightly older at diagnosis (6.1 vs. 4.7 years old, P = 0.08), with a higher proportion of female agreeing to participate compared with males (93.2 vs. 86.5%, P = 0.07).

CONCLUSION

The PETALE study will contribute to comprehensively characterize clinical, psychosocial, biologic, and genomic features of cALL survivors using an integrated approach. Expected outcomes include LAE early detection biomarkers, long-term follow-up guidelines, and recommendations for physicians and health professionals.

Managing CNS disease in adults with acute lymphoblastic leukemia

The central nervous system (CNS) is an important site of involvement by acute lymphoblastic leukemia (ALL) in adults. The prevalence is sufficiently high that prophylactic treatment is routinely given to this sanctuary site in order to eradicate occult disease that might otherwise lead to a relapse. A lumbar puncture should be routinely performed in all newly diagnosed patients with ALL. The risks of CNS leukemia vary by phenotype and genotype. Preventive treatment of the CNS during post-remission therapy has become an integral part of all current ALL treatment protocols. Most treatment regimens combine multiple doses of intrathecal chemotherapy with high-dose systemic methotrexate and/or cytarabine. Cranial irradiation is less commonly used for prophylaxis but is still the most effective treatment for overt CNS leukemia. Recurrences within the CNS usually coincide with or predict soon afterwards for systemic relapse in the marrow and blood.

Non-infectious chemotherapy-associated acute toxicities during childhood acute lymphoblastic leukemia therapy

During chemotherapy for childhood acute lymphoblastic leukemia, all organs can be affected by severe acute side effects, the most common being opportunistic infections, mucositis, central or peripheral neuropathy (or both), bone toxicities (including osteonecrosis), thromboembolism, sinusoidal obstruction syndrome, endocrinopathies (especially steroid-induced adrenal insufficiency and hyperglycemia), high-dose methotrexate-induced nephrotoxicity, asparaginase-associated hypersensitivity, pancreatitis, and hyperlipidemia. Few of the non-infectious acute toxicities are associated with clinically useful risk factors, and across study groups there has been wide diversity in toxicity definitions, capture strategies, and reporting, thus hampering meaningful comparisons of toxicity incidences for different leukemia protocols. Since treatment of acute lymphoblastic leukemia now yields 5-year overall survival rates above 90%, there is a need for strategies for assessing the burden of toxicities in the overall evaluation of anti-leukemic therapy programs.

How PET/MR Can Add Value For Children With Cancer

PURPOSE

To review how PET/MR technology could add value for pediatric cancer patients.

RECENT FINDINGS

Since many primary tumors in children are evaluated with MRI and metastases are detected with PET/CT, integrated PET/MR can be a time-efficient and convenient solution for pediatric cancer staging. 18F-FDG PET/MR can assess primary tumors and the whole body in one imaging session, avoid repetitive anesthesia and reduce radiation exposure compared to 18F-FDG PET/CT. This article lists 10 action points, which might improve the clinical value of PET/MR for children with cancer. However, even if PET/MR proves valuable, it cannot enter mainstream applications if it is not accessible to the majority of pediatric cancer patients. Therefore, innovations are needed to make PET/MR scanners affordable and increase patient throughput.

SUMMARY

PET/MR offers opportunities for more efficient, accurate and safe diagnoses of pediatric cancer patients. The impact on patient management and outcomes has to be substantiated by large-scale prospective clinical trials.

Brain structure, working memory and response inhibition in childhood leukemia survivors

INTRODUCTION

Survival rates for children with acute lymphoblastic leukemia (ALL) approach 95%. At the same time, there is growing concern that chemotherapy causes alterations in brain development and cognitive abilities. We performed MRI measurements of white and gray matter volume to explore how variation in brain structure may be related to cognitive abilities in ALL survivors and healthy controls.

METHODS

The sample included 24 male ALL survivors who had completed contemporary treatment 3-11 years prior, and 21 age- and sex-matched controls. Participants were between 8 and 18 years old. Working memory and motor response inhibition were measured with the N-Back and Stop Signal Tasks (SST), respectively. Participants underwent 3T structural MRI to assess white and gray matter volumes overall, lobe-wise, and in cortical and atlas-identified subcortical structures. Mental health was assessed with the Child Behavioral Checklist.

RESULTS

ALL survivors performed more poorly on measures of working memory and response inhibition than controls. Frontal and parietal white matter, temporal and occipital gray matter volume, and volumes of subcortical white and gray matter structures were significantly reduced in ALL survivors compared with controls. Significant structure-function correlations were observed between working memory performance and volume of the amygdala, thalamus, striatum, and corpus callosum. Response inhibition was correlated with frontal white matter volume. No differences were found in psychopathology.

CONCLUSIONS

Compared with controls, a reduction in volume across brain regions and tissue types, was detectable in ALL survivors years after completion of therapy. These structural alterations were correlated with neurocognitive performance, particularly in working memory. Confirming these observations in a larger, more representative sample of the population is necessary. Additionally, establishing the time course of these changes-and the treatment, genetic, and environmental factors that influence them-may provide opportunities to identify at-risk patients, inform the design of treatment modifications, and minimize adverse cognitive outcomes.

A Stroke Mimic: Methotrexate-induced Neurotoxicity in the Emergency Department

BACKGROUND

Acute lymphoblastic leukemia (ALL) is the most common form of childhood leukemia. The treatment of ALL involves multimodality therapy, and methotrexate (MTX) remains a mainstay of treatment. A complication of MTX therapy includes acute, subacute, and chronic neurotoxocity. Signs and symptoms may range from headaches, dizziness, and mood disorders to seizures and stroke-like symptoms.

CASE REPORT

An 18-year-old woman with a history of ALL presented to the emergency department with acute onset of right-sided facial paralysis, right upper extremity flaccid paralysis, and right lower extremity weakness after receiving MTX therapy 3 days earlier. Diagnostic studies were unremarkable and the patient was treated with oral dextromethorphan for presumed MTX-induced neurotoxicity. The patient's symptoms began to improve within hours and she was discharged home within 48 hours with no neurologic deficits. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Emergency physicians should be aware of this complication of MTX therapy given the sensitivity in regards to time with respect to cerebral vascular accidents. An awareness of this complication in the setting of the appropriate history and physical examination can lead to an accurate diagnosis and intervention and the avoidance of administering thrombolytics.

Posterior Reversible Encephalopathy Syndrome Associated With Dose-adjusted EPOCH (Etoposide, Prednisone, Vincristine, Cyclophosphamide, Doxorubicin) Chemotherapy

INTRODUCTION

The purpose of our study was to identify the key risk factors for the development of posterior reversible encephalopathy syndrome (PRES) after administration of the combination chemotherapy regimen, DA-EPOCH (dose-adjusted etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin).

MATERIALS AND METHODS

We performed a retrospective medical record review of patients receiving DA-EPOCH with or without rituximab (DA-EPOCH ± R) at our institution from July 2012 to September 2014. The patients were screened for evidence of severe neurotoxicity through identification of requests for neurology consultations or neuroimaging studies. Patients with evidence of central nervous system (CNS) neurotoxicity were reviewed in detail to identify documented cases of PRES. The key risk factors assessed included rituximab administration sequence, and the presence of CNS insults, fluid status or electrolyte abnormalities, organ dysfunction, and hypertension.

RESULTS

A total of 44 patients received DA-EPOCH ± R at our institution from July 2012 to September 2014. Of these 44 patients, 3 (7%) were diagnosed with PRES. The patients who developed PRES were more likely to have a pre-existing CNS insult, fluid status or electrolytes abnormalities, and hypertension.

CONCLUSION

To the best of our knowledge, the present study is the first description of PRES associated with DA-EPOCH. The key risk factors for the development of PRES identified in our study included hypertension, fluid imbalance, electrolyte abnormalities, baseline organ dysfunction, a high tumor burden, and the presence of pre-existing CNS insults during chemotherapy, such as CNS infection. Patients with these risk factors appear to have a greater risk of developing PRES and should be monitored closely during treatment.

FDG-Avid Intrathecal Inflammation Following Administration of Intrathecal Methotrexate

Intrathecal methotrexate is a standard option for central nervous system-directed therapy in patients with stage III and IV diffuse large B-cell lymphoma. We present a case of a 50-year-old man with stage IV diffuse large B-cell lymphoma with widespread lymphomatous involvement including the central nervous system, who received 7 doses of intrathecal methotrexate via Ommaya catheter. Posttherapy F-FDG-PET/CT imaging demonstrated diffuse, intense intrathecal FDG avidity, without correlative findings on MR spinal imaging. FDG avidity resolved on follow-up. These PET/CT findings are most consistent with methotrexate-induced thecal inflammation, which needs to be distinguished from intrathecal malignancy.

Central Nervous System Complications in Children Receiving Chemotherapy or Hematopoietic Stem Cell Transplantation

Therapy-related neurotoxicity greatly affects possibility of survival and quality of life of pediatric patients treated for cancer. Central nervous system (CNS) involvement is heterogeneous, varying from very mild and transient symptoms to extremely severe and debilitating, or even lethal syndromes. In this review, we will discuss the broad scenario of CNS complications and toxicities occurring during the treatment of pediatric patients receiving both chemotherapies and hematopoietic stem cell transplantation. Different types of complications are reviewed ranging from therapy related to cerebrovascular with a specific focus on neuroradiologic and clinical features.

The Role of the Central Nervous System Microenvironment in Pediatric Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is the most common cancer in children. While survival rates for ALL have improved, central nervous system (CNS) relapse remains a significant cause of treatment failure and treatment-related morbidity. Accordingly, there is a need to identify more efficacious and less toxic CNS-directed leukemia therapies. Extensive research has demonstrated a critical role of the bone marrow (BM) microenvironment in leukemia development, maintenance, and chemoresistance. Moreover, therapies to disrupt mechanisms of BM microenvironment-mediated leukemia survival and chemoresistance represent new, promising approaches to cancer therapy. However, in direct contrast to the extensive knowledge of the BM microenvironment, the unique attributes of the CNS microenvironment that serve to make it a leukemia reservoir are not yet elucidated. Recent work has begun to define both the mechanisms by which leukemia cells migrate into the CNS and how components of the CNS influence leukemia biology to enhance survival, chemoresistance, and ultimately relapse. In addition to providing new insight into CNS relapse and leukemia biology, this area of investigation will potentially identify targetable mechanisms of leukemia chemoresistance and self-renewal unique to the CNS environment that will enhance both the durability and quality of the cure for ALL patients.

Neurologic Complications after Allogeneic Hematopoietic Stem Cell Transplantation

Neurologic complications after hematopoietic stem cell transplantation are frequently life-threatening, and their clinical management can be highly challenging. A wide spectrum of causative factors-including drug-related toxicities; infections sustained by virus, bacteria, or invasive molds; metabolic encephalopathy; cerebrovascular disorders; immune-mediated disorders; and disease recurrence-may lead to potentially lethal complications. Moreover, given that some neurologic complications are not uncommonly diagnosed post mortem, their overall incidence is likely to be underestimated. Their prompt recognition and timely treatment are of paramount importance to reduce the risk for transplantation-related death.

Evaluation of standardized triple intrathecal therapy toxicity in oncohematological pediatric patients

Background The administration of triple intrathecal therapy with methotrexate, cytarabine and a corticosteroid for the prophylaxis and treatment of neoplastic cell infiltration in the central nervous system in hematological malignancies is a widespread practice. There is limited information available about its toxicity profile. Several factors related to intrathecal preparation can affect toxicity. Thus, it was decided to standardize intrathecal chemotherapy, trying to obtain the best toxicity profile. Objective To assess the toxicity of a standardized triple intrathecal chemotherapy in oncohematological pediatric patients and to establish risk factors of toxicity. Setting Oncohematological pediatric unit from a tertiary hospital in Spain. Methods Prospective, descriptive and observational study in which all the administrations of standardized triple intrathecal chemotherapy in pediatric patients were registered. Main outcome measure Toxicity of the intrathecal therapy was recorded and possible risk factors were assessed. Results A total of 269 administrations of triple intrathecal chemotherapy were registered in 41 patients (mean age = 6.6 ± 3.9 years). In 16.7% of the procedures, an adverse event was reported (total number of adverse events = 61). 47.5% were grade 1, 47.5% grade 2 and 4.9% grade 3. The administration of intrathecal chemotherapy inpatient and patient age ≥3 years were risk factors of toxicity in the multivariate analysis. Conclusions The administration of standardized triple intrathecal chemotherapy is related to a low frequency of toxicity and most of the adverse events registered were mild/moderate. The detection of adverse effects was significantly greater in children with age greater than or equal to three years and in hospitalized patients.

Preventing and Managing Toxicities of High-Dose Methotrexate

: High-dose methotrexate (HDMTX), defined as a dose higher than 500 mg/m2, is used to treat a range of adult and childhood cancers. Although HDMTX is safely administered to most patients, it can cause significant toxicity, including acute kidney injury (AKI) in 2%-12% of patients. Nephrotoxicity results from crystallization of methotrexate in the renal tubular lumen, leading to tubular toxicity. AKI and other toxicities of high-dose methotrexate can lead to significant morbidity, treatment delays, and diminished renal function. Risk factors for methotrexate-associated toxicity include a history of renal dysfunction, volume depletion, acidic urine, and drug interactions. Renal toxicity leads to impaired methotrexate clearance and prolonged exposure to toxic concentrations, which further worsen renal function and exacerbate nonrenal adverse events, including myelosuppression, mucositis, dermatologic toxicity, and hepatotoxicity. Serum creatinine, urine output, and serum methotrexate concentration are monitored to assess renal clearance, with concurrent hydration, urinary alkalinization, and leucovorin rescue to prevent and mitigate AKI and subsequent toxicity. When delayed methotrexate excretion or AKI occurs despite preventive strategies, increased hydration, high-dose leucovorin, and glucarpidase are usually sufficient to allow renal recovery without the need for dialysis. Prompt recognition and effective treatment of AKI and associated toxicities mitigate further toxicity, facilitate renal recovery, and permit patients to receive other chemotherapy or resume HDMTX therapy when additional courses are indicated.

IMPLICATIONS FOR PRACTICE

High-dose methotrexate (HDMTX), defined as a dose higher than 500 mg/m2, is used for a range of cancers. Although HDMTX is safely administered to most patients, it can cause significant toxicity, including acute kidney injury (AKI), attributable to crystallization of methotrexate in the renal tubular lumen, leading to tubular toxicity. When AKI occurs despite preventive strategies, increased hydration, high-dose leucovorin, and glucarpidase allow renal recovery without the need for dialysis. This article, based on a review of the current associated literature, provides comprehensive recommendations for prevention of toxicity and, when necessary, detailed treatment guidance to mitigate AKI and subsequent toxicity.

Influence of ADORA2A gene polymorphism on leukoencephalopathy risk in MTX-treated pediatric patients affected by hematological malignancies

BACKGROUND

Methotrexate (MTX) can lead to neurotoxicity and asymptomatic leukoencephalopathy. However, the mechanism of MTX-related leukoencephalopathy is obscure. MTX and its metabolites inhibit 5-aminoimidazole-4-carboxamide ribonucleotide formiltransferase (ATIC) and promote adenosine release. Recently, it has been reported that adenosine and its receptor are related to certain central nervous system diseases. We investigated whether adenosine pathway gene polymorphisms and clinical factors were related to MTX-related leukoencephalopathy in pediatric patients affected by hematological malignancies.

PROCEDURE

Fifty-six Japanese childhood acute lymphoblastic leukemia or lymphoma patients were investigated. Patients were evaluated by magnetic resonance imaging of the brain before maintenance therapy or stem cell transplantation. Gene polymorphisms within the adenosine pathway (ATIC, adenosine A2A receptor [ADORA2A]) and the MTX pathway (methylenetetrahydrofolate reductase [MTHFR] and ABCB1) were genotyped using TaqMan assays. Clinical data were collected by accessing the medical records. MTX-related leukoencephalopathy was evaluated by a pediatric neurologist.

RESULTS

Twenty-one (37%) of 56 patients developed MTX-related leukoencephalopathy. Four of 21 patients developed clinical neurotoxicity. The minor allele CC genotype of rs2298383 (ADORA2A) was associated with MTX-related leukoencephalopathy (P = 0.010, odds ratio = 5.81, 95% confidence interval 1.50-22.50). High cumulative dose of systemic MTX was associated with MTX-related leukoencephalopathy after adjusting for sex, ADORA2A polymorphism, and prolonged high MTX concentration (P = 0.042, odds ratio = 1.18, 95% confidence interval 1.01-1.37).

CONCLUSIONS

ADORA2A rs2298383 and high cumulative dose of systemic MTX administration were significantly associated with MTX-related leukoencephalopathy. Our results indicate that pharmacological intervention within the adenosine pathway may be both a treatment and preventative option for MTX-related leukoencephalopathy.

Drug interactions may be important risk factors for methotrexate neurotoxicity, particularly in pediatric leukemia patients

Purpose

Methotrexate administration is associated with frequent adverse neurological events during treatment for childhood acute lymphoblastic leukemia. Here, we present evidence to support the role of common drug interactions and low vitamin B₁₂ levels in potentiating methotrexate neurotoxicity.

Methods

We review the published evidence and highlight key potential drug interactions as well as present clinical evidence of severe methotrexate neurotoxicity in conjunction with nitrous oxide anesthesia and measurements of vitamin B₁₂ levels among pediatric leukemia patients during therapy.

Results

We describe a very plausible mechanism for methotrexate neurotoxicity in pediatric leukemia patients involving reduction in methionine and consequential disruption of myelin production. We provide evidence that a number of commonly prescribed drugs in pediatric leukemia management interact with the same folate biosynthetic pathways and/or reduce functional vitamin B₁₂ levels and hence are likely to increase the toxicity of methotrexate in these patients. We also present a brief case study supporting out hypothesis that nitrous oxide contributes to methotrexate neurotoxicity and a nutritional study, showing that vitamin B₁₂ deficiency is common in pediatric leukemia patients.

Conclusions

Use of nitrous oxide in pediatric leukemia patients at the same time as methotrexate use should be avoided especially as many suitable alternative anesthetic agents exist. Clinicians should consider monitoring levels of vitamin B₁₂ in patients suspected of having methotrexate-induced neurotoxic effects.