Abstract 3633: Disparities in relapse among a large multi-ethnic population of children diagnosed with acute lymphoblastic leukemia (ALL): A report from the Reducing Ethnic Disparities in Acute Leukemia (REDIAL) Consortium

Introduction: While end-induction minimal residual disease (MRD) is the strongest prognostic factor for relapsed ALL, approximately half of all relapses occur in children who are MRD negative. Latino ethnicity is also a risk factor for relapse. To further explore these associations, we conducted an interim analysis of risk factors for relapse in a large multi-ethnic population of children diagnosed with ALL.

Methods: The REDIAL Consortium includes patients diagnosed with ALL at six major pediatric cancer centers in the Southwestern U.S. The study period was 2004 to 2018, and we included individuals who were 1-23 years of age when diagnosed with ALL. Time to relapse was defined as time from ALL diagnosis to the initial relapse event, with individuals censored at date of death, last follow-up, or bone marrow transplant. Demographic and clinical factors evaluated included race/ethnicity (Latino, non-Latino Black, non-Latino White, non-Latino other), sex, age at diagnosis (1-5, 6-10, 11-15, >15 years), ALL immunophenotype (B-cell, T-cell), National Cancer Institute (NCI) risk group, central nervous system involvement, enrollment on a Children’s Oncology Group clinical trial, end-induction disease failure, and end-induction bone marrow flow cytometric MRD. Cox proportional hazards models were used to calculate adjusted hazards ratios (HRs) and 95% confidence intervals (CIs). Analyses were further stratified based on end-induction MRD status (positive ≥0.01%, negative <0.01%).

Results: Overall, there were 1,710 ALL patients with a median age at diagnosis of 5 years (interquartile range: 3-11 years). The majority of patients were Latino (60.1%) and male (56.9%). Of the 379 MRD-positive patients, 74 (19.5%) relapsed, compared to 138 of 1,233 (11.2%) MRD-negative patients (p<0.0001). In adjusted models, factors associated with a greater risk of relapse included MRD positivity (HR=1.72, 95% CI: 1.26-2.36), older age at diagnosis (>15 vs. 1-5 years, HR=1.98, 95% CI: 1.19-3.29), and NCI high-risk group (HR=1.74, 95% CI: 1.20-2.52), while patients enrolled on a clinical trial were less likely to relapse (HR=0.76, 95% CI: 0.57-0.99). Among MRD-positive patients, Latinos were less likely to relapse (HR=0.60, 95% CI: 0.33-0.99) compared to non-Latino Whites, whereas Latinos who were MRD negative were more likely to relapse (HR=1.68, 95% CI: 1.09-2.59).

Conclusion: In a large contemporary multi-ethnic cohort of >1,700 children with ALL, we observed significant disparities in relapse by MRD status, age at diagnosis, NCI risk group, clinical trial enrollment, and race/ethnicity. Notably, nearly 65% of relapse events occurred in MRD-negative patients. Further analyses are ongoing in REDIAL to evaluate the impact of other factors including cytogenetics and novel biomarkers of relapse.

Citation Format: Pagna Sok, Austin L. Brown, Olga A. Taylor, M. Brooke Bernhardt, Juan C. Bernini, Rodrigo A. Erana, Timothy Griffin, Kenneth Heym, Van T. Huynh, Laura Klesse, Kathleen Ludwig, Sandi L. Pruitt, Karen R. Rabin, Michael E. Scheurer, Philip J. Lupo. Disparities in relapse among a large multi-ethnic population of children diagnosed with acute lymphoblastic leukemia (ALL): A report from the Reducing Ethnic Disparities in Acute Leukemia (REDIAL) Consortium [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3633.

Abstract 3636: Ethnic disparities in methotrexate neurotoxicity during pediatric acute lymphoblastic leukemia therapy: A report from the Reducing Ethnic Disparities in Acute Leukemia (REDIAL) Consortium

Introduction: Methotrexate (MTX) is a key component of curative chemotherapy for pediatric acute lymphoblastic leukemia (ALL). However, delivery of MTX is often interrupted by dose-limiting acute neurotoxicity, which manifests as seizures, stroke-like symptoms, or altered mental status. Because incidence and risk factors for MTX neurotoxicity are poorly defined, we evaluated clinical and demographic predictors of MTX neurotoxicity using the multi-ethnic REDIAL Consortium.

Methods: The REDIAL cohort includes pediatric patients diagnosed with ALL at six treatment centers in the southwestern U.S. This interim analysis evaluated 756 patients age 1-21 years diagnosed with B-ALL (2005-2018). Electronic health records were reviewed to determine race/ethnicity (Latino, non-Latino White, non-Latino Black, or Other), body mass index, sex, age, and intravenous (IV) MTX dose. Applying Ponte di Legno criteria, acute MTX neurotoxicity was defined as neurologic episodes occurring <21 days from intrathecal or IV MTX, which resulted in MTX treatment modifications. The proportion of patients who experienced MTX neurotoxicity and corresponding 95% confidence interval (CI) was calculated overall and within the induction, post-induction, and maintenance treatment phases. Multivariable logistic regression was used to estimate adjusted odds ratios (aOR) for the association between clinical factors and MTX neurotoxicity.

Results: The study population was 56.6% Latino, 52.8% male, 41.4% treated with >5g/m2 IV MTX, and diagnosed at a median age of 5 years. Overall, 15.5% (95% CI: 12.9-18.3%) of patients experienced neurotoxic events (n=117), including 1.9% (n=14, 95% CI: 1.0-3.1%) during induction, 13.0% (n=98, 95% CI: 10.7-15.6%) during post-induction, and 0.7% (n=5, 95% CI: 0.2-1.5%) during maintenance therapy. Ethnic differences were not statistically significant during induction or maintenance phases. Compared to non-Latinos, post-induction neurotoxicity was significantly more frequent among Latinos (aOR = 2.87, 95% CI: 1.68-5.10), with disparities observed during consolidation, interim maintenance and delayed intensification phases. Exposure to >5g/m2 IV MTX (aOR = 2.16, 95% CI: 1.08-3.24) and older age at diagnosis (aOR = 1.16, 95% CI: 1.08-1.24) were also associated with a significantly more post-induction neurotoxicity. No factors evaluated were significantly associated with neurotoxicity during induction and maintenance therapy.

Conclusions: MTX neurotoxicity disproportionally affects Latino children during ALL post-induction therapy. Additional work is warranted to identify risk factors for neurotoxicity during induction and maintenance therapy as well as the specific clinical and host biological factors responsible for post-induction ethnic differences in MTX neurotoxicity.

Citation Format: Austin L. Brown, Rachel D. Harris, Olga A. Taylor, Melanie B. Bernhardt, Juan C. Bernini, Rodrigo A. Erana, Timothy Griffin, Kenneth Heym, Van T. Huynh, Kathleen Ludwig, Avner Meoded, Sandi L. Pruitt, Philip J. Lupo, Karen R. Rabin, Michael E. Scheurer. Ethnic disparities in methotrexate neurotoxicity during pediatric acute lymphoblastic leukemia therapy: A report from the Reducing Ethnic Disparities in Acute Leukemia (REDIAL) Consortium [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3636.

Association between fatigue and sleep disturbances during treatment for pediatric acute lymphoblastic leukemia and posttreatment neurocognitive performance

BACKGROUND

Survivors of pediatric acute lymphoblastic leukemia (ALL) are at increased risk of neurocognitive weakness in the areas of attention, executive function, and processing speed. Although fatigue and sleep disturbances are frequent complications of ALL therapy and associated with cognitive functions, the impact of fatigue and sleep profiles during active ALL treatment on posttreatment neurocognitive performance has received limited attention.

METHODS

Pediatric patients (n = 120) with ALL (diagnosed 2011-2016) who completed fatigue and sleep questionnaires at four time points during active treatment were enrolled in a study of neurocognitive performance. Latent class growth analysis identified subgroups of patients with similar sleep and fatigue profiles during treatment. Neurocognitive performance collected >6 months post treatment on 40 participants was compared between latent classes using multivariable linear regression models.

RESULTS

Participants (57.5% male and 79.1% Hispanic or non-Hispanic White) were classified into one of two fatigue and sleep profiles: Class 1 characterized by mild fatigue and sleep disturbances during treatment (50.8%), and Class 2 characterized by higher levels of fatigue and sleep disturbances (49.2%). Posttreatment cognitive performance was in the normal range for most measures, but significantly below normative means for executive function, verbal short-term memory, attention, and distractability measures. Compared to Class 1, Class 2 demonstrated significantly (p < .05) poorer posttreatment neurocognitive performance, particularly in measures of attention.

CONCLUSIONS

Our findings indicate that fatigue and sleep disturbances during the first year of pediatric ALL therapy may impact long-term neurocognitive performance. Sleep and fatigue may be targets for intervention to preserve cognitive functioning in survivors.

Abstract 2349: Comparison of the blood, bone marrow, and cerebrospinal fluid metabolomes in children with acute leukemia

Background: Children with acute leukemia (AL) are at risk for relapse, treatment toxicity, second neoplasms, and death. Understanding host and tumor response to therapy is necessary to achieve high survival rates and minimize adverse effects. Metabolomics, the characterization of small molecules in a biological system, may be useful for monitoring treatment response. In support of this, we previously identified metabolites in bone marrow (BM) plasma associated with end-induction minimal residual disease (MRD) and in cerebrospinal fluid (CSF) associated with fatigue. Because procedures for obtaining BM and CSF are invasive and subject patients to risk, we sought to determine whether the BM and CSF metabolomes of children undergoing therapy for AL were correlated with the blood metabolome.

Methods: Blood plasma, BM, and CSF were collected at the end-induction from 11 patients with newly diagnosed AL treated at Texas Children's Hospital (Houston, TX). Global metabolomic profiling was performed by Metabolon (Durham, NC), using liquid chromatography-tandem mass spectrometry according to published methods. We assessed the number and type (e.g. lipid, amino acid) of metabolites in each sample. For each metabolite identified in ≥2 samples from ≥2 patients, we computed Spearman rank correlation coefficients to estimate the pairwise correlations between blood, BM, and CSF.

Results: Patients were predominantly male (N=7) and Latino (N=9). Ten were diagnosed with B-cell acute lymphoblastic leukemia and one with mixed phenotype acute leukemia. Among 670 metabolites detected in ≥2 blood and BM plasma samples, 370 (58%) demonstrated moderate to strong correlations (Spearman's rho ≥0.5) and 317 (47%) were significant at p&lt;0.05. Among 340 metabolites detected in ≥2 blood and CSF samples, 135 (40%) demonstrated moderate to strong correlations and 96 (28%) were significant at p&lt;0.05. Among 318 metabolites detected in ≥2 BM plasma and CSF samples, 88 (28%) demonstrated moderate to strong correlations and 66 (21%) were significant at p&lt;0.05. We observed generally moderate to strong correlations between BM and blood for 19 metabolites we previously reported were associated with MRD (median rho 0.51, interquartile range 0.24-0.69). We observed a strong positive correlation between CSF and blood for one of three metabolites we previously reported were associated with fatigue (dimethylglycine, rho=0.7, p=0.02), and a moderate inverse correlation for a second (gamma-glutamylglutamine, rho=-0.51, p=012).

Conclusions: There is substantial correlation between the blood and BM plasma metabolomes at end-induction among children with ALL, including metabolites putatively associated with early treatment response. Correlations between CSF and blood or BM plasma are weaker, implying that the CSF metabolome is distinct. The blood plasma metabolome may approximate the BM but not CSF metabolome in children with ALL.

Citation Format: Jeremy M. Schraw, J.P. Woodhouse, Melanie B. Bernhardt, Olga A. Taylor, Terzah M. Horton, Michael E. Scheurer, Mehmet F. Okcu, Karen R. Rabin, Philip J. Lupo, Austin L. Brown. Comparison of the blood, bone marrow, and cerebrospinal fluid metabolomes in children with acute leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2349.

Ethnic Disparities in Methotrexate Neurotoxicity among Children and Adolescents with Acute Lymphoblastic Leukemia

Purpose of study: To identify factors related to the increased risk of neurotoxicity in children with acute lymphoblastic leukemia (ALL) after treatment with the antifolate agent methotrexate (MTX), a critical component of curative protocols. Methods: We analyzed the incidence of and factors associated with acute MTX neurotoxicity (neurologic episode within 14d of dose that resulted in treatment modification) in a multi-site study of 280 (48% Latino) newly diagnosed (between 2012–2017) patients treated on recent pediatric ALL protocols. We examined the effects of genetic ancestry and single nucleotide variants in a subset of 190 patients with genotype data. Results: MTX neurotoxicity occurred in 22% of Latino compared to 7% of non- Latino patients; a nearly 2.5-fold increased risk after accounting for other clinical and demographic factors. Patients with neurotoxicity received fewer total MTX doses, and their risk for relapse was 2-fold higher than patients who did not experience neurotoxicity. We also found that 42% of our Latino patients who experienced a first neurotoxic event went on to have additional events, compared to only 21% of non-Latino patients. The proportion of genetic variation that co-segregates with Native American ancestry was overrepresented in individuals with MTX-related neurotoxicity (mean = 35%) vs without neurotoxicity (mean = 23%, p = 0.025). In multivariable models accounting for sex, age at diagnosis, and treatment risk group, every 10% increase in the proportion of Native American genetic ancestry was associated with a 16% increase in neurotoxicity incidence (HR = 1.16; 95% CI: 1.02–1.32). Our data also suggest that Latinos are at higher risk for first (OR = 3.51, p = 0.02) and subsequent (OR = 6.10, p = 0.04) neurotoxic events associated with a missense variant in TCF12, which is more common in admixed Latino (23%) compared to European (3%) or African (&lt;1%) populations. Conclusions: MTX neurotoxicity is more common among Latino children and adolescents with ALL, compromises treatment efficacy, and may contribute to disparities in ALL relapse and survival. Our findings to date highlight that differences in inherited genetic variation, which segregate with ancestry, likely contribute to disparities in the incidence of treatment-related neurotoxicity.

Impact of Childhood Leukemia Treatment on Attention Measured by the Continuous Performance Test Factor Structure

OBJECTIVES

To describe the impact of central nervous system-directed treatment on attention and its relation to academic outcomes in childhood acute lymphoblastic leukemia (ALL) survivors.

SAMPLE & SETTING

51 children diagnosed with ALL at two pediatric oncology treatment centers in the southwestern United States.

METHODS & VARIABLES

A prospective, longitudinal design measured attention after a child was in remission, two years after the start of treatment, and at the end of treatment. Attention measures from the Conners' Continuous Performance Test were grouped into composite subdomains based on a factor structure describing focused attention, hyperactivity/impulsivity, sustained attention, and vigilance.

RESULTS

Children treated for ALL exhibited decreased focused attention, sustained attention, and vigilance during and at the end of treatment when compared to age- and gender-normed references.

IMPLICATIONS FOR NURSING

Pediatric oncology nurses are in a position to ask patients and parents about neuropsychological difficulties during ALL treatment. Patients who experience these effects are at risk for decreased academic abilities after treatment.

Childhood Cancer Symptom Cluster: Leukemia and Health-Related Quality of Life

OBJECTIVES

To examine the relationship of the Childhood Cancer Symptom Cluster-Leukemia (CCSC-L) with health-related quality of life (HRQOL).

SAMPLE & SETTING

327 children receiving treatment for acute lymphoblastic leukemia from four pediatric oncology programs across the United States.

METHODS & VARIABLES

Participants completed fatigue, sleep disturbance, pain, nausea, and depression symptom questionnaires at four time points; these symptoms comprised the CCSC-L. HRQOL was measured at the start of postinduction therapy and then at the start of maintenance therapy. Relationships between the CCSC-L and HRQOL scores were examined with longitudinal parallel-process modeling.

RESULTS

The mean HRQOL significantly increased over time (p < 0.001). The CCSC-L had a significant negative association with HRQOL scores at the start of postinduction therapy (beta = -0.53, p < 0.005) and the start of maintenance therapy (beta = -0.33, p < 0.015). Participants with more severe symptoms in the CCSC-L over time had significantly lower HRQOL at the start of maintenance therapy (beta = -0.42, p < 0.005).

IMPLICATIONS FOR NURSING

Nurses are pivotal in providing management strategies to minimize symptom severity that may improve HRQOL.

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.

Abstract 2967: Ethnic-specific risk of neurotoxocity and its impact on treatment outcomes among pediatric patients receiving acute lymphoblastic leukemia therapy

Purpose: Because of the increasing awareness that Hispanics diagnosed with acute lymphoblastic leukemia (ALL) often experience worse outcomes, we sought to evaluate the risk of methotrexate (MTX)-related neurotoxicity (NT) by ethnic group and evaluate its effects on treatment outcomes in a multi-institutional prospective cohort of pediatric patients (2-17 years old).

Methods: Patients with ALL were prospectively recruited from 3 pediatric cancer centers in the United States for the period 2012-2017 and systematically followed for the development of treatment-related symptoms and toxicities. For this analysis, suspected NT cases were defined as patients with a neurologic event following intrathecal (IT) and/or intravenous (IV) MTX that led to a change in subsequent MTX therapy. Cumulative incidence of MTX NT was calculated by ethnic group. Multivariable linear regression models were generated to compare treatment differences between patients with and without MTX NT. The frequency of all-cause and central nervous system (CNS) relapse was compared between patients with and without MTX NT using the log-rank test and Cox regression models.

Results: Of the 280 patients enrolled, 39 (13.9%) experienced MTX NT (median follow-up = 22.6 months; range: 1.3 - 55.6 months). Cumulative incidence of MTX NT was 21.8% among Hispanic patients compared to 7.0% among non-Hispanic patients (p &lt;0.001). After adjusting for relevant clinical characteristics, Hispanic patients were 2.74 times more likely to develop MTX NT compared to non-Hispanic white patients (95% CI: 1.21-6.19). Patients who experienced MTX NT received an average of 2.25 fewer doses of IT MTX (95% CI: 1.73-2.77), independent of treatment risk group, sex, or age. Six cases of MTX NT (15.4%) experienced all-cause relapse during the study period, compared to 13 (2.1%) patients without MTX NT (log-rank p = 0.0038). Similarly, CNS relapse was more frequent among patients with MTX NT (10.3%) than patients without NT (2.1%; log-rank p = 0.0014). In univariate Cox regression models, MTX NT was significantly associated with CNS relapse (HR: 3.80, 95% CI: 1.44-10.02), a trend which remained after individually accounting for treatment risk arm (HR: 2.92, 95% CI: 1.07-7.95), MRD status at day 29 (HR: 3.49, 95% CI: 1.32-9.24), race and ethnicity (HR: 3.15, 95% CI: 1.13-8.79), age at diagnosis (HR: 2.56, 95% CI: 0.91-7.21), and sex (HR: 3.82, 95% CI: 1.44-10.10).

Conclusion: We identified an increased risk of relapse, specifically in the CNS, among ALL patients following MTX NT, which was not fully explained by other clinical risk factors. Further, incidence of NT was higher among Hispanic patients in our clincs. This is particularly interesting given that Hispanic patients typically present with more favorable disease characterstics, yet often experience worse treatment outcomes.

Citation Format: Michael E. Scheurer, Olga A. Taylor, Austin L. Brown, Julienne Brackett, ZoAnne E. Dreyer, Ida (Ki) Moore, Pauline Mitby, Mary C. Hooke, Philip J. Lupo, Marilyn J. Hockenberry. Ethnic-specific risk of neurotoxocity and its impact on treatment outcomes among pediatric patients receiving acute lymphoblastic leukemia therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2967.

Influence of Nitrosative Stress on Fatigue During Childhood Leukemia Treatment

The focus on a cure for childhood leukemia over the last three decades has resulted in survival rates of more than 80%. However, efforts to manage leukemia-treatment symptoms have not kept pace with new therapies. Symptom toxicity during treatment can result in complications, treatment delays, and therapy dose reductions. Compromise in therapy can negatively influence the quality of life and, even more notably, jeopardize chances for long-term survival. This study examined biologic mechanisms that influence fatigue caused by increased reactive oxidative species (ROS) or actual failure of the antioxidant defense system due to genetic variation by investigating reactive nitrosative species, a "downstream" consequence of ROS. The specific aims of this study were to characterize the trajectory of nitrosative stress during acute lymphoblastic leukemia treatment and evaluate the influence of nitrosative stress on fatigue. A repeated measures design was used to evaluate the fatigue experienced by 186 children and adolescents, 3-18 years of age, with a diagnosis of leukemia during the most intense phase of treatment. An established biomarker of nitrosative stress, protein 3-nitrotyrosine (3NT) residues in the cerebral spinal fluid, was evaluated at diagnosis, postinduction, and consolidation phases of treatment. Higher fatigue was associated with higher 3NT levels at the beginning of treatment. Two distinct groups of children experienced either consistently high or consistently low 3NT levels across the treatment trajectory, from diagnosis to 12 months postinduction. Findings from this study support continued exploration into the phenotypic biochemical mechanisms that influence a reactive response to childhood cancer treatment.

Declines Noted in Cognitive Processes and Association With Achievement Among Children With Leukemia

PURPOSE/OBJECTIVES

To assess change in specific cognitive processes during treatment with chemotherapy only among children with acute lymphoblastic leukemia (ALL). 
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DESIGN

A prospective, repeated measures design.
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SETTING

Pediatric oncology treatment centers at Banner-University Medical Center Tucson/Banner Children's-Diamond Medical Center (University of Arizona) and Texas Children's Cancer and Hematology centers (Baylor College of Medicine) in Houston. 
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SAMPLE

71 children with ALL, with a mean age of 6.18 years at the time of diagnosis. 
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METHODS

Using mixed-effects latent growth curve modeling with time since diagnosis as a fixed effect, age-adjusted standardized measures of working memory, processing speed, executive function, and attention were obtained and repeated about one and two years later. A subsample was tested for academic achievement at the end of treatment.
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MAIN RESEARCH VARIABLES

Verbal working memory, visual spatial memory, processing speed, academic achievement, age, and gender. 
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FINDINGS

A significant main effect was observed for age at diagnosis on decline in verbal working memory during treatment. Planned contrasts revealed greater decline among children who were diagnosed when aged younger than five years compared to those diagnosed when aged five years or older. Decline in verbal working memory and achievement in letter-word identification and calculation skills were associated, and decline in spatial memory was associated with calculation. A main effect of gender was observed on processing speed, with female patients showing greater decline than male patients. 
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CONCLUSIONS

Findings from this study may guide the timing of interventions that could improve school achievement among survivors. 
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IMPLICATIONS FOR NURSING

Children undergoing treatment for ALL may experience issues with verbal working memory and increased difficulty in school. Nurses are in a position to refer parents and children to school resources for additional academic support.

Changes in Oxidant Defense, Apoptosis, and Cognitive Abilities During Treatment for Childhood Leukemia

Aggressive central nervous system (CNS)-directed treatment for acute lymphoblastic leukemia (ALL), the most prevalent cancer among children and adolescents, prevents metastasis of leukemia cells into the brain. Up to 60% of survivors experience cognitive problems, but knowledge about risk factors for and mechanisms of neurologic injury is lacking. Objectives of the present study were to (1) quantify changes in oxidant defense and apoptosis over the course of ALL therapy and (2) elucidate risk factors for long-term cognitive problems. The sample included 71 children with ALL. Cerebrospinal fluid (CSF) samples were collected at diagnosis and during intrathecal chemotherapy administration. Oxidant defense was measured by reduced glutathione (GSH), oxidized glutathione (GSSG), and the ratio of GSH:GSSG. Apoptosis was measured by activity of several cysteine-dependent aspartate-specific protease (abbreviated as caspase) enzymes that initiate (caspases 8 and 9) or execute (caspases 3/7) apoptosis. Cognitive abilities were assessed by standardized measures of short-term memory, visual-motor integration, and attention 3 years after ALL diagnosis. GSH and GSSG concentration increased significantly during ALL therapy, and a low GSH:GSSG ratio was indicative of an oxidized extracellular environment. Caspase enzyme activity increased significantly, and caspases 3/7 activity was significantly and negatively associated with performance on measures of cognitive abilities. Younger age at time of ALL diagnosis was associated with some measures of attention. Efflux of glutathione into CSF maintains oxidant defense by scavenging free radicals and other reactive oxygen species and is an early event in apoptosis. These mechanisms may be involved in neurologic injury associated with CNS-directed treatment and subsequent cognitive problems.

Oxidative Stress, Motor Abilities, and Behavioral Adjustment in Children Treated for Acute Lymphoblastic Leukemia

PURPOSE/OBJECTIVES

To examine associations among oxidative stress, fine and visual-motor abilities, and behavioral adjustment in children receiving chemotherapy for acute lymphoblastic leukemia (ALL)
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DESIGN

A prospective, repeated-measures design
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SETTING

Two pediatric oncology settings in the southwestern United States.

SAMPLE

89 children with ALL were followed from diagnosis to the end of chemotherapy.

METHODS

Serial cerebrospinal fluid samples were collected during scheduled lumbar punctures and analyzed for oxidative stress biomarkers. Children completed fine motor dexterity, visual processing speed, and visual-motor integration measures at three time points. Parents completed child behavior ratings at the same times.

MAIN RESEARCH VARIABLES

Oxidative stress, fine motor dexterity, visual processing, visual-motor integration, and behavioral adjustment
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FINDINGS

Children with ALL had below-average fine motor dexterity, visual processing speed, and visual-motor integration following the induction phase of ALL therapy. By end of therapy, visual processing speed normalized, and fine motor dexterity and visual-motor integration remained below average. Oxidative stress measures correlated with fine motor dexterity and visual-motor integration. Decreased motor functioning was associated with increased hyperactivity and anxiety
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CONCLUSIONS

Oxidative stress occurs following chemo-therapy for childhood ALL and is related to impaired fine motor skills and visual symptoms
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IMPLICATIONS FOR NURSING

Early intervention should be considered to prevent fine motor and visual-spatial deficits, as well as behavioral problems.

The influence of oxidative stress on symptom occurrence, severity, and distress during childhood leukemia treatment

PURPOSE/OBJECTIVES

To explore the symptom trajectory during the first 16 months of childhood leukemia treatment and any associations with the oxidative stress pathway measured by cerebrospinal fluid (CSF) concentration of oxidized phosphatidylcholine (PC), the predominant glycerophospholipid in the brain and cell membranes.

DESIGN

Prospective, longitudinal design.

SETTING

Two cancer centers in the southwestern United States.

SAMPLE

36 children (aged 3-14 years) newly diagnosed with acute lymphoblastic leukemia.

METHODS

Symptoms were measured using the Memorial Symptom Assessment Scale at six specific time points during treatment. Biochemical changes in oxidative stress were measured by oxidized PC in the CSF.

MAIN RESEARCH VARIABLES

Childhood cancer symptoms, oxidized PC.

FINDINGS

Significant differences were found in the number of symptoms experienced during the three phases of treatment. Symptom trajectory changes and influence of the oxidative stress pathway on symptom experiences were identified.

CONCLUSIONS

Symptoms experienced during treatment for childhood leukemia are associated with increased oxidative stress.

IMPLICATIONS FOR NURSING

Children with leukemia experience symptoms throughout treatment. Physiologic measures indicate the influence of oxidative stress on symptoms.

Evaluation of Biomarkers of Oxidative Stress and Apoptosis in Patients With Severe Methotrexate Neurotoxicity: A Case Series

Central nervous system (CNS) treatment is an essential part of acute lymphocytic leukemia (ALL) therapy, and the most common CNS treatment is intrathecal (IT) and high-dose intravenous (IV) methotrexate (MTX). Treatment with MTX may cause neurotoxicity, which is often accompanied by neurologic changes, delays in treatment, and prolonged hospital stays. This article reports clinical presentations of 3 patients with severe MTX toxicity as well as levels of oxidative stress and apoptosis biomarkers in cerebrospinal fluid (CSF). Oxidative stress was measured by oxidized phosphatidylcholine (PC), oxidized phosphatidylinositol (PI), and F2 isoprostanes; apoptosis was measured by caspase 3/7 activity. Most consistent biomarker changes in all 3 cases were increases in caspase 3/7 and F2 isoprostanes prior to acute toxicity while increases in oxidized phospholipids occurred slightly later. Progressive increases in F2 isoprostanes and caspase 3/7 activity prior to and/or during acute toxicity suggests MTX induces oxidative stress and an associated increase in apoptosis. These findings support the role of oxidative stress in MTX-related neurotoxicity.

F2-isoprostanes: a measure of oxidative stress in children receiving treatment for leukemia

Acute lymphoblastic leukemia (ALL) is the most prevalent and curable cancer among children and adolescents less than 15 years of age in the United States. Essential for cure of childhood ALL is prophylactic treatment of the central nervous system (CNS), with methotrexate (MTX) being the most widely used drug in this treatment. While CNS treatment has contributed to long-term disease-free survival, resulting declines in academic abilities have been reported. There is growing evidence that CNS treatment with MTX increases oxidative stress, a potential mechanism of CNS injury. This article reports changes in oxidative stress, measured by the biomarker F2-isoprostane (F2-IsoP), in the cerebrospinal fluid (CSF) in 47 children with ALL during the first 18 months of treatment. The number of CSF samples ranged from 5 to 14 during postinduction and from 1 to 9 during continuation. Total doses of intrathecal MTX during postinduction were significantly correlated with the mean and highest concentrations of F2-IsoP during postinduction and the mean concentration of F2-IsoP during continuation. F2-IsoP concentrations during postinduction and continuation were higher in children who received more than six doses of intrathecal MTX. New therapies for a highly curable disease such as childhood leukemia have the potential to be individualized in the future, requiring reliable molecular and biochemical markers, such as oxidative stress indicators. Innovative use of biomarkers has the potential to increase our understanding of treatment-related toxicities and associated symptoms and to inform future therapeutic approaches for optimizing cure and quality of life among children with leukemia.

Using Improvement Science to Promote Evidence-Based Practice in a Childhood Cancer and Hematology Center

A major children’s cancer and hematology center established a Quality Transformation (QT) Core to develop and monitor empirical outcomes that demonstrate excellence in clinical care. The QT Core, based on the Institute of Medicine’s domains of quality health care, aims to ensure that care is safe, effective, patient centered, timely, efficient, and equitable. Specific goals for the first year of the QT Core were to develop a team of improvement science experts, engage faculty and staff in QT initiatives, promote accountability for excellence in clinical care, and establish specific metrics to evaluate process, structure, and outcomes for QT Core projects. The purpose of this article is to discuss the successful development of a quality transformation core within a pediatric subspecialty and demonstrate the principles of improvement science through an actual quality transformation project designed to implement an evidence-based guideline for procedural sedation for children with cancer. The QT Core within this subspecialty was founded on principles of successful transformation of patient care that includes motivation to change, leaders committed to quality, active engagement of staff in meaningful problem-solving initiatives, alignment with organization goals with resource allocation, and integration to bridge boundaries throughout an organization. These key principles are demonstrated through the discussion of the development of the QT Core and implementation of an evidence-based procedure sedation guideline. Pediatric and pediatric subspecialty groups can be on the forefront of national initiatives that promote quality health care, exemplified by the QT Core developed within the cancer and hematology center.

Stigmasterol, a soy lipid-derived phytosterol, is an antagonist of the bile acid nuclear receptor FXR

Phytosterols, components of soy-derived lipids, are among the proposed exacerbants of parenteral nutrition-associated cholestasis (PNAC). We investigated whether phytosterols contribute to bile acid (BA)-induced hepatocyte damage by antagonizing a nuclear receptor (NR) critically involved in hepatoprotection from cholestasis, FXR (farnesoid X receptor, NR1H4). In HepG2 cells, stigmasterol acetate (StigAc), a water-soluble Stig derivative, suppressed ligand-activated expression of FXR target genes involved in adaptation to cholestasis (i.e. BSEP, FGF-19, OSTalpha/beta). Furthermore, StigAc antagonized BA-activated, FXR target genes SHP and BSEP in FXR+/+, but not in FXR-/- mouse hepatocytes. Both Stig and StigAc inhibited BA-activated, FXR-dependent reporter gene expression in transfected HepG2 cells, whereas the most prevalent phytosterol in lipids, beta-sitosterol, had no inhibitory effect. Finally, among six ligand-activated NR-ligand binding domains (LBDs) tested, antagonism by StigAc was specific to only two (FXR and PXR, pregnane X receptor, NR1I2). We demonstrate that Stig, a phytosterol prevalent in soy-derived PN lipid solutions, is a potent in vitro antagonist of the NR for bile acids FXR.