Incidence, survival, and mortality of cancer in children and young adolescents in Belgium and the Netherlands in 2004-2015: A comparative population-based study.

International comparisons of cancer surveillance measures may provide insight into inequalities in registration practices, etiological factors, and treatment strategies. This study aimed to compare incidence, survival, and mortality of cancer in children and young adolescents between Belgium and the Netherlands. All children (0-14 years) and young adolescents (15-17 years) diagnosed with cancer between 2004 and 2015 were selected from the population-based cancer registries of Belgium (N = 4739) and the Netherlands (N = 7322). Differences in incidence and mortality were expressed as standardized rate ratios (SRR; BE/NL). Five-year observed survival was calculated using the Kaplan-Meier method. During 2004-2015, the overall cancer incidence among children and young adolescents was similar in both countries. Incidence of neuroblastoma was significantly higher in Belgian children (2010-2015: SRR = 1.3, 95% CI 1.0-1.6). Five-year survival of all malignant cancers was comparable in 2010-2015, exceeding 80% in both age groups. Remarkable differences in survival existed in children for malignant central nervous system (CNS) tumors in 2004-2009 (BE = 62%, NL = 45%), for acute myeloid leukemia (BE = 68%, NL = 78%) and rhabdomyosarcomas (BE = 60%, NL = 79%) in 2010-2015, and for neuroblastoma in both periods (2004-2009: BE = 76%, NL = 64%; 2010-2015: BE = 82%, NL = 64%). Overall cancer mortality in children decreased by approximately 3 percent-points annually in both countries, but was slightly lower in Belgium in 2004-2009 (SRR = 0.9, 95% CI 0.7-1.0). Despite differences for specific cancer types, overall cancer incidence, survival, and mortality were comparable between Dutch and Belgian children and young adolescents in 2010-2015. Variability in screening, diagnosis, and registration practices probably explains the observed differences in incidence and survival of neuroblastoma and malignant CNS tumors.

BEHAV3D: a 3D live imaging platform for comprehensive analysis of engineered T cell behavior and tumor response.

Modeling immuno-oncology by using patient-derived material and immune cell co-cultures can advance our understanding of immune cell tumor targeting in a patient-specific manner, offering leads to improve cellular immunotherapy. However, fully exploiting these living cultures requires analysis of the dynamic cellular features modeled, for which protocols are currently limited. Here, we describe the application of BEHAV3D, a platform that implements multi-color live 3D imaging and computational tools for: (i) analyzing tumor death dynamics at both single-organoid or cell and population levels, (ii) classifying T cell behavior and (iii) producing data-informed 3D images and videos for visual inspection and further insight into obtained results. Together, this enables a refined assessment of how solid and liquid tumors respond to cellular immunotherapy, critically capturing both inter- and intratumoral heterogeneity in treatment response. In addition, BEHAV3D uncovers T cell behavior involved in tumor targeting, offering insight into their mode of action. Our pipeline thereby has strong implications for comparing, prioritizing and improving immunotherapy products by highlighting the behavioral differences between individual tumor donors, distinct T cell therapy concepts or subpopulations. The protocol describes critical wet lab steps, including co-culture preparations and fast 3D imaging with live cell dyes, a segmentation-based image processing tool to track individual organoids, tumor and immune cells and an analytical pipeline for behavioral profiling. This 1-week protocol, accessible to users with basic cell culture, imaging and programming expertise, can easily be adapted to any type of co-culture to visualize and exploit cell behavior, having far-reaching implications for the immuno-oncology field and beyond.

Pharmacokinetics of PEGasparaginase in Infants with Acute Lymphoblastic Leukemia.

BACKGROUND: PEGasparaginase is known to be a critical drug for treating pediatric acute lymphoblastic leukemia (ALL), however, there is insufficient evidence to determine the optimal dose for infants who are less than one year of age at diagnosis. This international study was conducted to identify the pharmacokinetics of PEGasparaginase in infants with newly diagnosed ALL and gather insight into the clearance and dosing of this population. METHODS: Infants with ALL who received treatment with PEGasparaginase were included in our population pharmacokinetic assessment employing non-linear mixed effects modelling (NONMEM). RESULTS: 68 infants with ALL, with a total of 388 asparaginase activity samples, were included. PEGasparaginase doses ranging from 400 to 3,663 IU/m2 were administered either intravenously or intramuscularly. A one-compartment model with time-dependent clearance, modeled using a transit model, provided the best fit to the data. Body weight was significantly correlated with clearance and volume of distribution. The final model estimated a half-life of 11.7 days just after administration, which decreased to 1.8 days 14 days after administration. Clearance was 19.5% lower during the post-induction treatment phase compared to induction. CONCLUSION: The pharmacokinetics of PEGasparaginase in infants diagnosed under one year of age with ALL is comparable to that of older children (1-18 years). We recommend a PEGasparaginase dosing at 1,500 IU/m2 for infants without dose adaptations according to age, and implementing therapeutic drug monitoring as standard practice.

Continuous PEGasparaginase Dosing Reduces Hypersensitivity Reactions in Pediatric ALL: A Dutch Childhood Oncology Group ALL11 Randomized Trial.

PURPOSE: The primary objective of this randomized study was to determine whether a continuous dosing schedule (without the asparaginase-free interval) would result in less hypersensitivity reactions to PEGasparaginase (PEGasp) compared with the standard noncontinuous dosing schedule. METHODS: Eight hundred eighteen patients (age 1-18 years) with ALL were enrolled in the Dutch Childhood Oncology Group-ALL11 protocol and received PEGasp. Three hundred twelve patients stratified in the medium-risk arm were randomly assigned to receive 14 individualized PEGasp doses once every two weeks in either a noncontinuous or continuous schedule after the first three doses in induction (EudraCT: 2012-000067-25). Hypersensitivity reactions were defined as allergies, allergic-like reactions, and silent inactivation. Secondary end points were other asparaginase-related toxicities, asparaginase activity and antibody levels, and outcome. RESULTS: During induction, 27 of 818 patients (3.3%) experienced hypersensitivity reactions. After random assignment, 4 of 155 (2.6%) in the continuous treatment arm versus 17 of 157 (10.8%) patients in the noncontinuous treatment arm had hypersensitivity reactions (P < .01), of which two (1.3%) versus 13 (8.3%) were inactivating reactions (P < .01). The occurrence of inactivating hypersensitivity reactions was seven times lower in the continuous arm (odds ratio, 0.15 [0.032-0.653]). In addition, antibody levels were significantly lower in the continuous arm (P < .01). With exception of a lower incidence of increased amylase in the continuous arm, there were no significant differences in total number of asparaginase-associated toxicities between arms. However, the timing of the toxicities was associated with the timing of the asparaginase administrations. No difference in 5-year cumulative incidence of relapse, death, or disease-free survival was found between both treatment arms. CONCLUSION: A continuous dosing schedule of PEGasp is an effective approach to prevent antibody formation and inactivating hypersensitivity reactions. The continuous PEGasp schedule did not increase toxicity and did not affect the efficacy of the therapy.

Physical frailty deteriorates after a 5-day dexamethasone course in children with acute lymphoblastic leukemia, results of a national prospective study.

BACKGROUND: Dexamethasone is important in the treatment for pediatric acute lymphoblastic leukemia (ALL) but induces muscle atrophy with negative consequences for muscle mass, muscle strength, and functional abilities. The aim of this study was to establish the effect of a dexamethasone course on sarcopenia and physical frailty in children with ALL, and to explore prognostic factors. METHODS: Patients with ALL aged 3-18 years were included during maintenance therapy. Patients had a sarcopenia/frailty assessment on the first day of (T1) and on the day after (T2) a 5-day dexamethasone course. Sarcopenia was defined as low muscle strength in combination with low muscle mass. Prefrailty and frailty were defined as having two or ≥three of the following components, respectively: low muscle mass, low muscle strength, fatigue, slow walking speed, and low physical activity. Chi-squared and paired t-tests were used to assess differences between T1 and T2. Logistic regression models were estimated to explore patient- and therapy-related prognostic factors for frailty on T2. RESULTS: We included 105 patients, 61% were boys. Median age was 5.3 years (range: 3-18.8). At T1, sarcopenia, prefrailty, and frailty were observed in respectively 2.8%, 23.5%, and 4.2% of patients. At T2, the amount of patients with frailty had increased to 17.7% (p = 0.002), whereas the number of patients with sarcopenia and prefrailty remained similar. Higher ASMM (odds ratio [OR]: 0.49, 95% CI: 0.28-0.83), stronger handgrip strength (OR: 0.41, 95% CI: 0.22-0.77) and more physical activity minutes per day (OR: 0.98, 95% CI: 0.96-0.99) decreased the risk of frailty at T2. Slower walking performance (OR: 2, 95% CI: 1.2-3.39) increased the risk. Fatigue levels at T1 were not associated with frailty at T2. CONCLUSION: Physical frailty increased strikingly after a 5-days dexamethasone course in children with ALL. Children with poor physical state at start of the dexamethasone course were more likely to be frail after the course.

Safety of mRNA-based COVID-19 vaccination in paediatric patients with a PEG-asparaginase allergy.

Background: Children treated for a malignancy are at risk to develop serious illness from a COVID-19 infection. Pegylated E. coli asparaginase (PEG-asparaginase) is used in the treatment of acute lymphoblastic leukemia. Allergy to this drug is common and both asparaginase and polyethylene glycol (PEG) are identified as possible antigens. The mRNA-based vaccines against COVID-19 contain PEG as a stabilizing component. Methods: We developed a protocol to be able to safely vaccinate children with a PEG-asparaginase allergy. All patients with a history of allergy to PEG-asparaginase have been included and skin prick testing for various PEGs was performed before vaccination with the mRNA Pfizer-BioNTech COVID-19 vaccine. Results: Twelve children between six and 16 years old were vaccinated, without allergic reaction. None of them got a positive skin prick test for PEG. Ten patients had pre-existing IgG or IgM antibodies against PEG. Conclusion: Children with a PEG-asparaginase allergy can be safely vaccinated against COVID-19 with mRNA vaccines containing PEG irrespective of IgG/IgM antibodies to PEG-asparaginase. Routine skin prick testing in patients with PEG-asparaginase allergy does not seem to be of added value.

Patient-Level Meta-analysis of Clofarabine in Acute Lymphoblastic Leukemia.

INTRODUCTION: Clofarabine monotherapy at a dose of 52 mg/m2 per day was approved in the USA in 2004 for the treatment of relapsed or refractory acute lymphoblastic leukemia (R/R ALL) in patients aged 1-21 years after at least two prior regimens. To address a post-marketing requirement for additional evidence of the clinical benefit of clofarabine in its approved indication, a meta-analysis of patient-level data was conducted. METHODS: A systematic literature review was conducted, using the Dr.Evidence software platform, DOC Search, and Embase, to identify clinical trials with patients with R/R ALL who received clofarabine monotherapy at 52 mg/m2. The primary endpoint was complete remission (CR). Secondary endpoints were overall remission (OR, defined by CR or CR with either incomplete platelet recovery or incomplete neutrophil and platelet recovery), duration of response, overall survival (OS), and safety. RESULTS: A total of 754 patients in 12 clinical studies were analyzed including 682 patients with R/R ALL treated with clofarabine monotherapy at 52 mg/m2; of them, 374 were aged < 22 years (pediatric population). Rates of CR and OR were 16% (95% confidence interval [CI] 7, 26) and 28% (95% CI 20, 37), respectively, in the pediatric population and 12% (95% CI 5, 21) and 21% (95% CI 13, 31) in the overall population. Median OS (evaluable in three studies in pediatric patients) was 3.7 months (95% CI 0.1, 31.4), reaching 10.1 months (95% CI 0.3, 68.9) for those achieving OR. Sensitivity analyses supported these findings. The most frequent grade 3-4 adverse events were liver abnormalities, anemia, diarrhea, and febrile neutropenia. CONCLUSION: In this meta-analysis, CR duration and median OS in pediatric patients with R/R ALL appeared to be slightly longer than in the phase II study. No new safety signals were identified. Results support the use of clofarabine monotherapy in its approved indication.

Advancing Diagnostics and Therapy to Reach Universal Cure in Childhood ALL.

Systemic combination chemotherapy and intrathecal chemotherapy markedly increased the survival rate of children with ALL. In the past two decades, the use of minimal (measurable) residual disease (MRD) measurements early in therapy improved risk group stratification with subsequent treatment intensifications for patients at high risk of relapse, and enabled a reduction of treatment for low-risk patients. The recent development of more sensitive MRD technologies may further affect risk stratification. Molecular genetic profiling has led to the discovery of many new subtypes and their driver genetic alterations. This increased our understanding of the biological basis of ALL, improved risk classification, and enabled implementation of precision medicine. In the past decade, immunotherapies, including bispecific antibodies, antibody-drug conjugates, and cellular therapies directed against surface proteins, led to more effective and less toxic therapies, replacing intensive chemotherapy courses and allogeneic stem-cell transplantation in patients with relapsed and refractory ALL, and are now being tested in newly diagnosed patients. It has taken 50-60 years to increase the cure rate in childhood ALL from 0% to 90% by stepwise improvements in chemotherapy. This review provides an overview of how the developments over the past 10-15 years mentioned above have significantly changed the diagnostic and treatment approach in ALL, and discusses how the integrated use of molecular and immunotherapeutic insights will very likely direct efforts to cure those children with ALL who are not cured today, and improve the quality of life for survivors who should have decades of life ahead. Future efforts must focus on making effective, yet very expensive, new technologies and therapies available to children with ALL worldwide.

CRISPR-Cas9 Library Screening Identifies Novel Molecular Vulnerabilities in KMT2A-Rearranged Acute Lymphoblastic Leukemia.

In acute lymphoblastic leukemia (ALL), chromosomal translocations involving the KMT2A gene represent highly unfavorable prognostic factors and most commonly occur in patients less than 1 year of age. Rearrangements of the KMT2A gene drive epigenetic changes that lead to aberrant gene expression profiles that strongly favor leukemia development. Apart from this genetic lesion, the mutational landscape of KMT2A-rearranged ALL is remarkably silent, providing limited insights for the development of targeted therapy. Consequently, identifying potential therapeutic targets often relies on differential gene expression, yet the inhibition of these genes has rarely translated into successful therapeutic strategies. Therefore, we performed CRISPR-Cas9 knock-out screens to search for genetic dependencies in KMT2A-rearranged ALL. We utilized small-guide RNA libraries directed against the entire human epigenome and kinome in various KMT2A-rearranged ALL, as well as wild-type KMT2A ALL cell line models. This screening approach led to the discovery of the epigenetic regulators ARID4B and MBD3, as well as the receptor kinase BMPR2 as novel molecular vulnerabilities and attractive therapeutic targets in KMT2A-rearranged ALL.

Modelling acquired resistance to DOT1L inhibition exhibits the adaptive potential of KMT2A-rearranged acute lymphoblastic leukemia.

In KMT2A-rearranged acute lymphoblastic leukemia (ALL), an aggressive malignancy, oncogenic KMT2A-fusion proteins inappropriately recruit DOT1L to promote leukemogenesis, highlighting DOT1L as an attractive therapeutic target. Unfortunately, treatment with the first-in-class DOT1L inhibitor pinometostat eventually leads to non-responsiveness. To understand this we established acquired pinometostat resistance in pediatric KMT2A::AFF1+ B-ALL cells. Interestingly, these cells became mostly independent of DOT1L-mediated H3K79 methylation, but still relied on the physical presence of DOT1L, HOXA9 and the KMT2A::AFF1 fusion. Moreover, these cells selectively lost the epigenetic regulation and expression of various KMT2A-fusion target genes such as PROM1/CD133, while other KMT2A::AFF1 target genes, including HOXA9 and CDK6 remained unaffected. Concomitantly, these pinometostat-resistant cells showed upregulation of several myeloid-associated genes, including CD33 and LILRB4/CD85k. Taken together, this model comprehensively shows the adaptive potential of KMT2A-rearranged ALL cells upon losing dependency on one of its main oncogenic properties.

The utility of a portable muscle ultrasound in the assessment of muscle alterations in children with acute lymphoblastic leukaemia.

BACKGROUND: During treatment for acute lymphoblastic leukaemia (ALL), children are prone to musculoskeletal deterioration. However, non-invasive tools to measure muscle mass and intramuscular alterations are limited. In this study we explored the feasibility of muscle ultrasound in children with ALL. Additionally, we analysed whether automated ultrasound outcomes of muscle size and intramuscular fat infiltration (IMAT) were associated with appendicular skeletal muscle mass (ASMM), muscle strength and physical performance. METHODS: Children with ALL, aged 3-18 years were included during maintenance therapy. Bilateral images of the rectus femoris muscle were captured using a portable linear array transducer connected to a tablet. Subsequently, an automated image annotation software (MuscleSound) was used to estimate cross-sectional area, muscle thickness and IMAT. Feasibility was assessed using acceptance (percentage of children approached who were enrolled), practicality (percentage of children that completed the ultrasound measurement after enrolment) and implementation (percentage of children that had sufficient imaging to be processed and analysed by the software). Assessments of ASMM by bioimpedance analysis, muscle strength using handheld dynamometry and timed physical performance tests were administered at the same visit. Multivariable linear models were estimated to study the associations between muscle ultrasound outcomes and ASMM, strength and physical performance, adjusted for sex, age, body mass index and ALL treatment week. RESULTS: Muscle ultrasound was performed in 60 out of 73 invited patients (76.9%), of which 37 were boys (61.7%), and median age was 6.1 years (range: 3-18.8 years). The acceptance was 98.7%, practicality 77.9% and implementation was 100%. Patients who refused the examination (n = 13) were younger (median: 3.6, range: 3-11.2 years) compared with the 60 examined children (P = 0.0009). In multivariable models, cross-sectional area was associated with ASMM (ß = 0.49 Z-score, 95% confidence interval [CI]:0.3,2.4), knee-extension strength (ß = 16.9 Newton [N], 95% CI: 4.8, 28.9), walking performance (ß = -0.46 s, 95% CI: -0.75, -0.18) and rising from the floor (ß = -1.07 s, 95% CI: -1.71, -0.42). Muscle thickness was associated with ASMM (ß = 0.14 Z-score, 95% CI: 0.04, 0.24), knee-extension strength (ß = 4.73 N, 95% CI: 0.99, 8.47), walking performance (ß = -0.13 s, 95% CI: -0.22, -0.04) and rising from the floor (ß = -0.28 s, 95% CI: -0.48, -0.08). IMAT was associated with knee-extension strength (ß = -6.84 N, 95% CI: -12.26, -1.41), walking performance (ß = 0.2 s, 95% CI: 0.08, 0.32) and rising from the floor (ß = 0.54 s, 95% CI: 0.27, 0.8). None of the muscle ultrasound outcomes was associated with handgrip strength. CONCLUSIONS: Portable muscle ultrasound appears a feasible and useful tool to measure muscle size and intramuscular alterations in children with ALL. Validation studies using magnetic resonance imaging (gold standard) are necessary to confirm accuracy in paediatric populations.

Outcome for Children and Young Adults With T-Cell ALL and Induction Failure in Contemporary Trials.

PURPOSE: Historically, patients with T-cell acute lymphoblastic leukemia (T-ALL) who fail to achieve remission at the end of induction (EOI) have had poor long-term survival. The goal of this study was to examine the efficacy of contemporary therapy, including allogeneic hematopoietic stem cell transplantation (HSCT) in first remission (CR1). METHODS: Induction failure (IF) was defined as the persistence of at least 5% bone marrow (BM) lymphoblasts and/or extramedullary disease after 4-6 weeks of induction chemotherapy. Disease features and clinical outcomes were reported in 325 of 6,167 (5%) patients age 21 years and younger treated in 14 cooperative study groups between 2000 and 2018. RESULTS: With a median follow-up period of 6.4 years (range, 0.3-17.9 years), the 10-year overall survival (OS) was 54.7% (SE = 2.9), which is significantly higher than the 27.6% (SE = 2.9) observed in the historical cohort from 1985 to 2000. There was no significant impact of sex, age, white blood cell count, central nervous system disease status, T-cell maturity, or BM disease burden at EOI on OS. Postinduction complete remission (CR) was achieved in 93% of patients with 10-year OS of 59.6% (SE = 3.1%) and disease-free survival (DFS) of 56.3% (SE = 3.1%). Among the patients who achieved CR, 72% underwent HSCT and their 10-year DFS (with a 190-day landmark) was significantly better than nontransplanted patients (63.8% [SE = 3.6] v 45.5% [SE = 7.1]; P = .005), with OS of 66.2% (SE = 3.6) versus 50.8% (SE = 6.8); P = .10, respectively. CONCLUSION: Outcomes for patients age 21 years and younger with T-ALL and IF have improved in the contemporary treatment era with a DFS benefit among those undergoing HSCT in CR1. However, outcomes still lag considerably behind those who achieve remission at EOI, warranting investigation of new treatment approaches.

Improved Outcome for ALL by Prolonging Therapy for IKZF1 Deletion and Decreasing Therapy for Other Risk Groups.

PURPOSE: The ALL10 protocol improved outcomes for children with ALL by stratifying and adapting therapy into three minimal residual disease-defined risk groups: standard risk, medium risk (MR), and high risk. IKZF1-deleted (IKZF1del) ALL in the largest MR group still showed poor outcome, in line with protocols worldwide, accounting for a high number of overall relapses. ALL10 showed high toxicity in Down syndrome (DS) and excellent outcome in ETV6::RUNX1 ALL. Poor prednisone responders (PPRs) were treated as high risk in ALL10. In ALL11, we prolonged therapy for IKZF1del from 2 to 3 years. We reduced therapy for DS by omitting anthracyclines completely, for ETV6::RUNX1 in intensification, and for PPR by treatment as MR. METHODS: Eight hundred nineteen patients with ALL (age, 1-18 years) were enrolled on ALL11 and stratified as in ALL10. Results were compared with those in ALL10. RESULTS: The five-year overall survival (OS), event-free survival (EFS), cumulative risk of relapse (CIR), and death in complete remission on ALL11 were 94.2% (SE, 0.9%), 89.0% (1.2), 8.2% (1.1), and 2.3% (0.6), respectively. Prolonged maintenance for IKZF1del MR improved 5-year CIR by 2.2-fold (10.8% v 23.4%; P = .035) and EFS (87.1% v 72.3%; P = .019). Landmark analysis at 2 years from diagnosis showed a 2.9-fold reduction of CIR (25.6%-8.8%; P = .008) and EFS improvement (74.4%-91.2%; P = .007). Reduced therapy did not abrogate 5-year outcome for ETV6::RUNX1 (EFS, 98.3%; OS, 99.4%), DS (EFS, 87.0%; OS, 87.0%), and PPR (EFS, 81.1%; OS, 94.9%). CONCLUSION: Children with IKZF1del ALL seem to benefit from prolonged maintenance therapy. Chemotherapy was successfully reduced for patients with ETV6::RUNX1, DS, and PPR ALL. It has to be noted that these results were obtained in a nonrandomized study using a historical control group.

A joint international consensus statement for measuring quality of survival for patients with childhood cancer.

The aim of treating childhood cancer remains to cure all. As survival rates improve, long-term health outcomes increasingly define quality of care. The International Childhood Cancer Outcome Project developed a set of core outcomes for most types of childhood cancers involving relevant international stakeholders (survivors; pediatric oncologists; other medical, nursing or paramedical care providers; and psychosocial or neurocognitive care providers) to allow outcome-based evaluation of childhood cancer care. A survey among healthcare providers (n = 87) and online focus groups of survivors (n = 22) resulted in unique candidate outcome lists for 17 types of childhood cancer (five hematological malignancies, four central nervous system tumors and eight solid tumors). In a two-round Delphi survey, 435 healthcare providers from 68 institutions internationally (response rates for round 1, 70-97%; round 2, 65-92%) contributed to the selection of four to eight physical core outcomes (for example, heart failure, subfertility and subsequent neoplasms) and three aspects of quality of life (physical, psychosocial and neurocognitive) per pediatric cancer subtype. Measurement instruments for the core outcomes consist of medical record abstraction, questionnaires and linkage with existing registries. This International Childhood Cancer Core Outcome Set represents outcomes of value to patients, survivors and healthcare providers and can be used to measure institutional progress and benchmark against peers.

Unraveling Dexamethasone-Induced Neurobehavioral and Sleep Problems in Children With ALL: Which Determinants Are Important?

PURPOSE: Dexamethasone, the preferred corticosteroid in most treatment protocols for pediatric acute lymphoblastic leukemia (ALL), can induce undesirable side effects. Neurobehavioral and sleep problems are frequently reported, but the interpatient variability is high. We therefore aimed to identify determinants for parent-reported dexamethasone-induced neurobehavioral and sleep problems in pediatric ALL. METHODS: Our prospective study included patients with medium-risk ALL and their parents during maintenance treatment. Patients were assessed before and after one 5-day dexamethasone course. Primary end points were parent-reported dexamethasone-induced neurobehavioral and sleep problems, measured with the Strengths and Difficulties Questionnaire and Sleep Disturbance Scale for Children, respectively. Analyzed determinants included patient and parent demographics, disease and treatment characteristics, parenting stress (Parenting Stress Index and Distress Thermometer for Parents), dexamethasone pharmacokinetics, and genetic variation (candidate single-nucleotide polymorphisms rs41423247 and rs4918). Statistically significant determinants identified in univariable logistic regression analyses were incorporated in a multivariable model. RESULTS: We included 105 patients: median age was 5.4 years (range, 3.0-18.8) and 61% were boys. Clinically relevant dexamethasone-induced neurobehavioral and sleep problems were reported by parents in 70 (67%) and 61 (59%) patients, respectively. In our multivariable regression models, we identified parenting stress as a significant determinant for parent-reported neurobehavioral (odds ratio [OR], 1.16; 95% CI, 1.07 to 1.26) and sleep problems (OR, 1.06; 95% CI, 1.02 to 1.10). Furthermore, parents who experienced more stress before start of a dexamethasone course reported more sleep problems in their child (OR, 1.16; 95% CI, 1.02 to 1.32). CONCLUSION: We identified parenting stress, and not dexamethasone pharmacokinetics, genetic variation, patient/parent demographics, or disease/treatment characteristics, as a significant determinant for parent-reported dexamethasone-induced neurobehavioral and sleep problems. Parenting stress may be a modifiable target to reduce these problems.

The Prognostic Effect of IKZF1 Deletions in ETV6::RUNX1 and High Hyperdiploid Childhood Acute Lymphoblastic Leukemia.

IKZF1 deletions are an established prognostic factor in childhood acute lymphoblastic leukemia (ALL). However, their relevance in patients with good risk genetics, namely ETV6::RUNX1 and high hyperdiploid (HeH), ALL remains unclear. We assessed the prognostic impact of IKZF1 deletions in 939 ETV6::RUNX1 and 968 HeH ALL patients by evaluating data from 16 trials from 9 study groups. Only 3% of ETV6::RUNX1 cases (n = 26) were IKZF1-deleted; this adversely affected survival combining all trials (5-year event-free survival [EFS], 79% versus 92%; P = 0.02). No relapses occurred among the 14 patients with an IKZF1 deletion treated on a minimal residual disease (MRD)-guided protocols. Nine percent of HeH cases (n = 85) had an IKZF1 deletion; this adversely affected survival in all trials (5-year EFS, 76% versus 89%; P = 0.006) and in MRD-guided protocols (73% versus 88%; P = 0.004). HeH cases with an IKZF1 deletion had significantly higher end of induction MRD values (P = 0.03). Multivariate Cox regression showed that IKZF1 deletions negatively affected survival independent of sex, age, and white blood cell count at diagnosis in HeH ALL (hazard ratio of relapse rate [95% confidence interval]: 2.48 [1.32-4.66]). There was no evidence to suggest that IKZF1 deletions affected outcome in the small number of ETV6::RUNX1 cases in MRD-guided protocols but that they are related to higher MRD values, higher relapse, and lower survival rates in HeH ALL. Future trials are needed to study whether stratifying by MRD is adequate for HeH patients or additional risk stratification is necessary.