Relapse risk following truncation of pegylated asparaginase in childhood acute lymphoblastic leukemia.

Truncation of asparaginase treatment due to asparaginase-related toxicities or silent inactivation (SI) is common and may increase relapse risk in acute lymphoblastic leukemia (ALL). We investigated relapse risk following suboptimal asparaginase exposure among 1401 children aged 1 to 17 years, diagnosed with ALL between July 2008 and February 2016, treated according to the Nordic Society of Pediatric Hematology and Oncology (NOPHO) ALL2008 protocol (including extended asparaginase exposure [1000 IU/m2 intramuscularly weeks 5-33]). Patients were included with delayed entry at their last administered asparaginase treatment, or detection of SI, and followed until relapse, death, secondary malignancy, or end of follow-up (median, 5.71 years; interquartile range, 4.02-7.64). In a multiple Cox model comparing patients with (n = 358) and without (n = 1043) truncated asparaginase treatment due to clinical toxicity, the adjusted relapse-specific hazard ratio (HR; aHR) was 1.33 (95% confidence interval [CI], 0.86-2.06; P = .20). In a substudy including only patients with information on enzyme activity (n = 1115), the 7-year cumulative incidence of relapse for the 301 patients with truncation of asparaginase treatment or SI (157 hypersensitivity, 53 pancreatitis, 14 thrombosis, 31 other, 46 SI) was 11.1% (95% CI, 6.9-15.4) vs 6.7% (95% CI, 4.7-8.6) for the 814 remaining patients. The relapse-specific aHR was 1.69 (95% CI, 1.05-2.74, P=.03). The unadjusted bone marrow relapse-specific HR was 1.83 (95% CI, 1.07-3.14, P=.03) and 1.86 (95% CI, 0.90- 3.87, P=.095) for any central nervous system relapse. These results emphasize the importance of therapeutic drug monitoring and appropriate adjustment of asparaginase therapy when feasible. This trial was registered at www.clinicaltrials.gov as #NCT03987542.

Effects of germline DHFR and FPGS variants on methotrexate metabolism and relapse of leukemia.

Methotrexate (MTX) during maintenance therapy is essential for curing acute lymphoblastic leukemia (ALL), but dosing strategies aiming at adequate treatment intensity are challenged by interindividual differences in drug disposition. To evaluate genetic factors associated with MTX metabolism, we performed a genome-wide association study in 447 ALL cases from the Nordic Society for Pediatric Haematology and Oncology ALL2008 study, validating results in an independent set of 196 patients. The intergenic single-nucleotide polymorphism rs1382539, located in a regulatory element of DHFR, was associated with increased levels of short-chain MTX polyglutamates (P = 1.1 × 10-8) related to suppression of enhancer activity, whereas rs35789560 in FPGS (p.R466C, P = 5.6 × 10-9) was associated with decreased levels of long-chain MTX polyglutamates through reduced catalytic activity. Furthermore, the FPGS variant was linked with increased relapse risk (P = .044). These findings show a genetic basis for interpatient variability in MTX response and could be used to improve future dosing algorithms.

Characteristics of white blood cell count in acute lymphoblastic leukemia: A COST LEGEND phenotype-genotype study.

BACKGROUND: White blood cell count (WBC) as a measure of extramedullary leukemic cell survival is a well-known prognostic factor in acute lymphoblastic leukemia (ALL), but its biology, including impact of host genome variants, is poorly understood. METHODS: We included patients treated with the Nordic Society of Paediatric Haematology and Oncology (NOPHO) ALL-2008 protocol (N = 2347, 72% were genotyped by Illumina Omni2.5exome-8-Bead chip) aged 1-45 years, diagnosed with B-cell precursor (BCP-) or T-cell ALL (T-ALL) to investigate the variation in WBC. Spline functions of WBC were fitted correcting for association with age across ALL subgroups of immunophenotypes and karyotypes. The residuals between spline WBC and actual WBC were used to identify WBC-associated germline genetic variants in a genome-wide association study (GWAS) while adjusting for age and ALL subtype associations. RESULTS: We observed an overall inverse correlation between age and WBC, which was stronger for the selected patient subgroups of immunophenotype and karyotypes (ρBCP-ALL  = -.17, ρT-ALL  = -.19; p < 3 × 10-4 ). Spline functions fitted to age, immunophenotype, and karyotype explained WBC variation better than age alone (ρ = .43, p << 2 × 10-6 ). However, when the spline-adjusted WBC residuals were used as phenotype, no GWAS significant associations were found. Based on available annotation, the top 50 genetic variants suggested effects on signal transduction, translation initiation, cell development, and proliferation. CONCLUSION: These results indicate that host genome variants do not strongly influence WBC across ALL subsets, and future studies of why some patients are more prone to hyperleukocytosis should be performed within specific ALL subsets that apply more complex analyses to capture potential germline variant interactions and impact on WBC.

TPMT polymorphisms and minimal residual disease after 6-mercaptopurine post-remission consolidation therapy of childhood acute lymphoblastic leukaemia.

Bone marrow minimal residual disease (MRD) is the strongest predictor of relapse in children with acute lymphoblastic leukemia (ALL). 6-mercaptopurine (6MP) in ALL therapy has wide inter-individual variation in disposition and is strongly influenced by polymorphisms in the thiopurine methyltransferase (TPMT) gene. In 952 patients treated according to the NOPHO ALL2008 protocol, we explored the association between thiopurine disposition, TPMT genotypes and MRD levels after consolidation therapy with 6MP, high-dose methotrexate (HD-MTX), asparaginase, and vincristine. The levels of the cytotoxic DNA-incorporated thioguanine were significantly higher on day 70-79 in G460A/A719G TPMT heterozygous (TPMTHZ) compared to TPMT wild type (TPMTWT) patients (mean: 230.7 vs. 149.7 fmol/µg DNA, p = 0.002). In contrast, TPMT genotype did not associate with the end of consolidation MRD levels irrespective of randomization of the patients to fixed dose (25 mg/m2/day) or 6MP escalation (up to 50 or 75 mg/m2/day) during consolidation therapy.

Impact of body mass index on relapse in children with acute lymphoblastic leukemia treated according to Nordic treatment protocols.

OBJECTIVES: High body mass index (BMI) is associated with poorer survival in childhood acute lymphoblastic leukemia (ALL), but the actual impact on the risk of relapse still needs to be clarified. We evaluated the impact of BMI at diagnosis on the risk of relapse in children with ALL treated according to Nordic Society of Paediatric Haematology and Oncology (NOPHO) protocols. METHOD: In a multicenter study, we collected data on BMI at diagnosis and outcome of 2558 children aged 2.0-17.9 years diagnosed between 1992 and 2016. Patients were divided into four groups according to International Obesity Task Force (IOTF) childhood BMI cut-offs: underweight, <17; healthy weight, 17-25; overweight, 25-30; and obese, ≥30 kg/m2 . RESULTS: In Cox multivariate regression analyses, an increased risk of relapse was observed in children aged 10-17.9 years with unhealthy BMI at diagnosis (underweight hazard ratio HR: 2.90 [95% confidence interval: 1.24-6.78], P = .01; overweight, HR: 1.95 [1.11-3.43], P = .02, and obese HR: 4.32 [95% 2.08-8.97], P < .001), compared to children with healthy weight. BMI had no impact on relapse in children under 10 years of age. CONCLUSION: High BMI, and especially obesity at diagnosis, is an independent adverse prognostic factor for relapse in older children with ALL.

Genetic predisposition to PEG-asparaginase hypersensitivity in children treated according to NOPHO ALL2008.

Asparaginase is essential in childhood acute lymphoblastic leukaemia (ALL) treatment, however hypersensitivity reactions to pegylated asparaginase (PEG-asparaginase) hampers anti-neoplastic efficacy. Patients with PEG-asparaginase hypersensitivity have been shown to possess zero asparaginase enzyme activity. Using this measurement to define the phenotype, we investigated genetic predisposition to PEG-asparaginase hypersensitivity in a genome-wide association study (GWAS). From July 2008 to March 2016, 1494 children were treated on the Nordic Society of Paediatric Haematology and Oncology ALL2008 protocol. Cases were defined by clinical hypersensitivity and no enzyme activity, controls had enzyme activity ≥ 100 iu/l and no hypersensitivity symptoms. PEG-asparaginase hypersensitivity was reported in 13·8% (206/1494) of patients. Fifty-nine cases and 772 controls fulfilled GWAS inclusion criteria. The CNOT3 variant rs73062673 on 19q13.42, was associated with PEG-asparaginase allergy (P = 4·68 × 10-8 ). We further identified two signals on chromosome 6 in relation to HLA-DQA1 (P = 9·37 × 10-6 ) and TAP2 (P = 1·59 × 10-5 ). This study associated variants in CNOT3 and in the human leucocyte antigen (HLA) region with PEG-asparaginase hypersensitivity, suggesting that not only genetic variations in the HLA region, but also regulation of these genes are of importance in the biology of this toxicity. Furthermore, our study emphasizes the importance of using asparaginase enzyme activity measurements to identify PEG-asparaginase hypersensitivity.

Low burden of minimal residual disease prior to transplantation in children with very high risk acute lymphoblastic leukaemia: The NOPHO ALL2008 experience.

The population-based Nordic/Baltic acute lymphoblastic leukaemia (ALL) Nordic Society for Paediatric Haematology and Oncology (NOPHO) ALL2008 protocol combined minimal residual disease (MRD)-driven treatment stratification with very intense first line chemotherapy for patients with high risk ALL. Patients with MRD ≥5% at end of induction or ≥10-3 at end of consolidation or following two high risk blocks were eligible for haematopoietic cell transplantation (HCT) in first remission. After at least three high risk blocks a total of 71 children received HCT, of which 46 had MRD ≥5% at end of induction. Ten patients stratified to HCT were not transplanted; 12 received HCT without protocol indication. Among 69 patients with evaluable pre-HCT MRD results, 22 were MRD-positive, one with MRD ≥10-3 . After a median follow-up of 5·5 years, the cumulative incidence of relapse was 23·5% (95% confidence interval [CI]: 10·5-47·7) for MRD-positive versus 5·1% (95% CI: 1·3-19·2), P = 0·02) for MRD-negative patients. MRD was the only variable significantly associated with relapse (hazard ratio 9·1, 95% CI: 1·6-51·0, P = 0·012). Non-relapse mortality did not differ between the two groups, resulting in disease-free survival of 85·6% (95% CI: 75·4-97·2) and 67·4% (95% CI: 50·2-90·5), respectively. In conclusion, NOPHO block treatment efficiently reduced residual leukaemia which, combined with modern transplant procedures, provided high survival rates, also among pre-HCT MRD-positive patients.

Individualized 6-mercaptopurine increments in consolidation treatment of childhood acute lymphoblastic leukemia: A NOPHO randomized controlled trial.

OBJECTIVES: This randomized controlled trial tested the hypothesis that children with non-high-risk acute lymphoblastic leukemia could benefit from individualized 6-mercaptopurine increments during consolidation therapy (NCT00816049). Primary and secondary end points were end of consolidation minimal residual disease (MRD) positivity and event-free survival. METHODS: 392 patients were randomized to experimental and 396 to standard therapy. Patients allocated to standard therapy received oral 6-mercaptopurine (25 mg/m2 /day) from days 30 to 85, while the experimental arm received stepwise increments of additional 25 mg/m2 /day beginning on days 50 and/or 71 unless dose-limiting myelosuppression had occurred. RESULTS: In the experimental arm, 166 patients (42%) received one dose increment, and 62 (16%) received two. Fifty-seven of 387 (15%) patients in the experimental arm were MRD positive at end of consolidation vs 77 of 389 (20%) in the control arm (P = .08). Five-year probability of event-free survival was 0.89 (95% CI: 0.85-0.93) in the experimental arm vs 0.93 (0.90-0.96) in the control arm (P = .13). The median accumulated length of 6-mercaptopurine treatment interruptions was 7 (IQR 2-12) in the experimental arm vs 4 (IQR 0-10) in the control arm (P = .002). CONCLUSION: This study found no benefit from individualized 6-mercaptopurine increments compared to standard therapy.

Health-related quality of life and psychological distress in young adult survivors of childhood cancer and their association with treatment, education, and demographic factors.

PURPOSE: This study investigated health-related quality of life (HRQOL) and psychological distress among young adult (YA) survivors of childhood cancer and the association of these measures with treatment, education, and demographic factors ≥ 5 years post diagnosis. METHODS: Participants included cancer survivors (n = 91) recruited through the Cancer Registry of Norway (CRN) and healthy controls (n = 223) recruited from a student population. All participants completed self-report questionnaires, and the Pediatric Quality of Life Inventory (PedsQL™) 4.0 and the Hopkins Symptom Checklist-10 (HSCL-10) as a measure of HRQOL and distress, respectively. RESULTS: Survivors reported HRQOL at the same level as controls, except for poorer physical functioning. Survivors in general, and female survivors specifically, had higher odds than controls of reporting symptoms of distress above cut-off, but survivors did not have higher mean levels of distress compared to controls. Survivors reporting distress levels above the cut-off had significantly poorer HRQOL regarding physical functioning and lower total PedsQL scores than controls scoring above the cut-off. Age (for HRQOL only), female gender, low educational level, and perceived low economic status significantly predicted HRQOL and distress. Education interacted with the effect of cranial radiation in predicting HRQOL. CONCLUSIONS: Survivors reported similar mean levels of HRQOL and distress as controls, except for physical functioning. For cancer survivors, demographic variables predicted HRQOL and distress. Some groups of survivors require closer follow-up, and more attention should be paid to factors associated with poor HRQOL and psychological distress in survivors, including female gender, lower education level, and lower income. Survivors treated with cranial radiation may be particular vulnerable in combination with low education regarding HRQOL.

DNA-thioguanine nucleotide concentration and relapse-free survival during maintenance therapy of childhood acute lymphoblastic leukaemia (NOPHO ALL2008): a prospective substudy of a phase 3 trial.

BACKGROUND: Adjustment of mercaptopurine and methotrexate maintenance therapy of acute lymphoblastic leukaemia by leucocyte count is confounded by natural variations. Cytotoxicity is primarily mediated by DNA-incorporated thioguanine nucleotides (DNA-TGN). The aim of this study was to establish whether DNA-TGN concentrations in blood leucocytes during maintenance therapy are associated with relapse-free survival. METHODS: In this substudy of the NOPHO ALL2008 phase 3 trial done in 23 hospitals in seven European countries (Denmark, Estonia, Finland, Iceland, Lithuania, Norway, and Sweden), we analysed data from centralised and blinded analyses of 6-mercaptopurine and methotrexate metabolites in blood samples from patients with non-high-risk childhood acute lymphoblastic leukaemia. Eligible patients were aged 1·0-17·9 years; had been diagnosed with non-high-risk precursor B-cell or T-cell leukaemia; had been treated according to the Nordic Society of Pediatric Hematology and Oncology ALL2008 protocol; and had reached maintenance therapy in first remission. Maintenance therapy was (mercaptopurine 75 mg/m2 once per day and methotrexate 20 mg/m2 once per week, targeted to a leucocyte count of 1·5-3·0 × 109 cells per L). We measured DNA-TGN and erythrocyte concentrations of TGN nucleotides, methylated mercaptopurine metabolites, and methotrexate polyglutamates. The primary objective was the association of DNA-TGN concentrations and 6-mercaptopurine and methotrexate metabolites with relapse-free survival. The secondary endpoint was the assessment of DNA-TGN concentration and 6-mercaptopurine and methotrexate metabolites during maintenance therapy phase 2. FINDINGS: Between Nov 26, 2008 and June 14, 2016, 1509 patients from the NOPHO ALL2008 study were assessed for eligibility in the DNA-TGN substudy, of which 918 (89%) of 1026 eligible patients had at least one DNA-TGN measurement and were included in the analyses. Median follow-up was 4·6 years (IQR 3·1-6·1). Relapse-free survival was significantly associated with DNA-TGN concentration (adjusted hazard ratio 0·81 per 100 fmol/µg DNA increase, 95% CI 0·67-0·98; p=0·029). In patients with at least five blood samples, erythrocyte concentrations of TGN, methylated mercaptopurine metabolites, and methotrexate polyglutamates were associated with DNA-TGN concentration (all p<0·0001). INTERPRETATION: Our results suggest the need for intervention trials to identify clinically applicable strategies for individualised drug dosing to increase DNA-TGN concentration, and randomised studies to investigate whether such strategies improve cure rates compared with current dose adjustments based on white blood cell counts. FUNDING: Danish Cancer Society, Childhood Cancer Foundation (Denmark), Childhood Cancer Foundation (Sweden), Nordic Cancer Union, Otto Christensen Foundation, University Hospital Rigshospitalet, and Novo Nordic Foundation.

Host genome variations and risk of infections during induction treatment for childhood acute lymphoblastic leukaemia.

OBJECTIVES: To investigate association of host genomic variation and risk of infections during treatment for childhood acute lymphoblastic leukaemia (ALL). METHODS: We explored association of 34,000 single-nucleotide polymorphisms (SNPs) related primarily to pharmacogenomics and immune function to risk of infections among 69 ALL patients on induction therapy. RESULTS: Forty-eight (70%) patients experienced infectious events including 23 with positive blood cultures. Infectious events and positive blood cultures were associated significantly with 24 and 21 SNPs, respectively (P < 0.01). Classification and regression tree analysis demonstrated rs11033797 (OR51F1), rs2835265 (CBR1), rs28627172 (POLDIP3) and rs1129844 (CCL11) to be predictive of outcome. Among 61 patients for whom read-outs were available for all four SNPs, 40 of 41 patients with the worst SNP profile experienced at least one infectious event compared with five of the remaining 20 patients (Hazard ratio 9.0, 95% CI 3.4-23.5, which was unchanged after adjustments for neutrophil counts). Pathway analysis identified variations in 'G-protein-coupled receptor (GPCR) downstream signalling', 'Bile acid and bile salt metabolism' and 'Class I MHC-mediated antigen processing and presentation' to be highly predictive of infections. CONCLUSIONS: Our data indicate that host genomic profiling may predict the risk of infections during induction therapy. This may facilitate development of individualised supportive care.

Intelligence and executive function are associated with age at insult, time post-insult, and disability following chronic pediatric acquired brain injury.

Background: Pediatric acquired brain injury (pABI) profoundly affects cognitive functions, encompassing IQ and executive functions (EFs). Particularly, young age at insult may lead to persistent and debilitating deficits, affecting daily-life functioning negatively. This study delves into the intricate interplay of age at insult, time post-insult, and their associations with IQ and EFs during chronic (>1 year) pABI. Additionally, we investigate cognitive performance across different levels of global function, recognizing the multifaceted nature of developmental factors influencing outcomes. Methods: Drawing upon insult data and baseline information analyzing secondary outcomes from a multicenter RCT, including comprehensive medical and neuropsychological assessments of participants aged 10 to 17 years with pABI and parent-reported executive dysfunctions. The study examined associations between age at insult (early, EI; ≤7y vs. late, LI; > 7y) and time post-insult with IQ and EFs (updating, shifting, inhibition, and executive attention). Additionally, utilizing the Pediatric Glasgow Outcome Scale-Extended, we explored cognitive performance across levels of global functioning. Results: Seventy-six participants, median 8 years at insult and 5 years post-insult, predominantly exhibiting moderate disability (n = 38), were included. Notably, participants with LI demonstrated superior IQ, executive attention, and shifting compared to EI, [adjusted mean differences with 95% Confidence Intervals (CIs); 7.9 (1.4, 14.4), 2.48 (0.71, 4.24) and 1.73 (0.03, 3.43), respectively]. Conversely, extended post-insult duration was associated with diminished performances, evident in mean differences with 95% CIs for IQ, updating, shifting, and executive attention compared to 1-2 years post-insult [-11.1 (-20.4, -1.7), -8.4 (-16.7, -0.1), -2.6 (-4.4, -0.7), -2.9 (-4.5, -1.2), -3.8 (-6.4, -1.3), -2.6 (-5.0, -0.3), and -3.2 (-5.7, -0.8)]. Global function exhibited a robust relationship with IQ and EFs. Conclusion: Early insults and prolonged post-insult durations impose lasting tribulations in chronic pABI. While confirmation through larger studies is needed, these findings carry clinical implications, underscoring the importance of vigilance regarding early insults. Moreover, they dispel the notion that children fully recover from pABI; instead, they advocate equitable rehabilitation offerings for pABI, tailored to address cognitive functions, recognizing their pivotal role in achieving independence and participation in society. Incorporating disability screening in long-term follow-up assessments may prove beneficial.

Spectrum of clinical presentations in familial hemophagocytic lymphohistiocytosis type 5 patients with mutations in STXBP2.

Hemophagocytic lymphohistiocytosis (HLH) is an often-fatal hyperinflammatory syndrome characterized by fever, hepatosplenomegaly, cytopenia, and in some cases hemophagocytosis. Here, we describe the mutation analysis, clinical presentation, and functional analysis of natural killer (NK) cells in patients with mutations in STXBP2 encoding Munc18-2, recently associated with familial HLH type 5. The disease severity among 11 persons studied here was highly variable and, accordingly, age at diagnosis ranged from 2 months to 17 years. Remarkably, in addition to typical manifestations of familial HLH (FHL), the clinical findings included colitis, bleeding disorders, and hypogammaglobulinemia in approximately one-third of the patients. Laboratory analysis revealed impairment of NK-cell degranulation and cytotoxic capacity. Interleukin-2 stimulation of lymphocytes in vitro rescued the NK cell-associated functional defects. In conclusion, familial HLH type 5 is associated with a spectrum of clinical symptoms, which may be a reflection of impaired expression and function of Munc18-2 also in cells other than cytotoxic lymphocytes. Mutations in STXBP2 should thus also be considered in patients with clinical manifestations other than those typically associated with HLH.

Pneumocystis jiroveci pneumonia prophylaxis during maintenance therapy influences methotrexate/6-mercaptopurine dosing but not event-free survival for childhood acute lymphoblastic leukemia.

Trimethoprim-sulfamethoxazole (TMP/SMX) is used in children with acute lymphoblastic leukemia (ALL) to prevent Pneumocystis pneumonia (PCP). We explored to which extent TMP/SMX influenced methotrexate (MTX)/6-mercaptopurine (6MP) dosage, myelosuppression, and event-free survival (EFS) during maintenance therapy. Of 447 study patients treated by the NOPHO ALL92 protocol, 120 patients received TMP/SMX continuously for 2-7 d/wk (TMP/SMX(2-7) ) and 287 patients never received TMP/SMX (TMP/SMX(never) ). Ten patients (all TMP/SMX(never) ) developed PCP, eight of which occurred within 7 months from the start of maintenance therapy. The TMP/SMX(2-7) group received lower oral 6MP doses than TMP/SMX(never) patients (50.6 vs. 63.9 mg/m(2) /d; P<0.001) but had lower absolute neutrophil counts (ANC) (median 1.7 vs. 2.0 × 10(9) /L; P<0.001). In Cox multivariate analysis, higher ANC levels (P=0.04) and male gender (P=0.06) were related to reduced EFS. ANC had no effect on EFS among TMP/SMX(2-7) patients (P=0.40) but did for TMP/SMX(never) patients (P=0.02). The difference in the effect on EFS between TMP/SMX(2-7) and TMP/SMX(never) patients was not significant (P=0.46). EFS did not differ between TMP/SMX(2-7) and TMP/SMX(never) patients (0.83 vs. 0.83; P=0.82). These results suggest that TMP/SMX is effective in preventing PCP and may have an antileukemic effect. TMP/SMX should be given the entire duration of maintenance therapy.

The Norwegian childhood cancer biobank.

BACKGROUND: The rapidly expanding era of "omics" research is highly dependent on the availability of quality-proven biological material, especially for rare conditions such as pediatric malignancies. Professional biobanks provide such material, focusing on standardized collection and handling procedures, distinctive quality measurements, traceability of storage conditions, and accessibility. For pediatric malignancies, traditional tumor biobanking is challenging due to the rareness and limited amount of tissue and blood samples. The higher molecular heterogeneity, lower mutation rates, and unique genomic landscapes, however, renders biobanking of this tissue even more crucial. AIM: The aim of this study was to test and establish methods for a prospective and centralized biobank for infants, children, and adolescents up to 18 years of age diagnosed with cancer in Norway. METHODS: Obtain judicial and ethical approvals and administration through a consortium, steering committee, and advisory board. Develop pipelines including SOPs for all aspects in the biobank process, including collection, processing and storing of samples and data, as well of quality controlling, safeguarding, distributing, and transport. RESULTS: The childhood cancer biobanking started at Oslo University Hospital in March 2017 and was from 2019 run as a national Norwegian Childhood Cancer Biobank. Informed consent and biological samples are collected regionally and stored centrally. Approximately 12 000 samples from 510 patients and have been included by January 1, 2021, representing a 96% consent and participation rate among our newly diagnosed patients. CONCLUSION: A well-functioning nationwide collection and centralized biobank with standardized procedures and national storage for pediatric malignancies has been established with a high acceptance among families.

DNA-thioguanine concentration and relapse risk in children and young adults with acute lymphoblastic leukemia: an IPD meta-analysis.

Methotrexate/6-mercaptopurine maintenance therapy improves acute lymphoblastic leukemia (ALL) outcome. Cytotoxicity is mediated by DNA incorporation of thioguanine nucleotides (DNA-TG). We investigated the association of DNA-TG to relapse risk in 1 910 children and young adults with non-high risk ALL. In a cohort-stratified Cox regression analysis adjusted for sex, age, and white cell count at diagnosis, the relapse-specific hazard ratio (HRa) per 100 fmol/µg increase in weighted mean DNA-TG (wmDNA-TG) was 0.87 (95% CI 0.78-0.97; p = 0.013) in the 839 patients who were minimal residual disease (MRD) positive at end of induction therapy (EOI), whereas this was not the case in EOI MRD-negative patients (p = 0.76). Validation analysis excluding the previously published Nordic NOPHO ALL2008 pediatric cohort yielded a HRa of 0.92 (95% CI 0.82-1.03; p = 0.15) per 100 fmol/µg increase in wmDNA-TG in EOI MRD-positive patients. If also excluding the United Kingdom cohort, in which samples were taken non-randomly in selected patients, the HRa for the EOI MRD-positive patients was 0.82 (95% CI 0.68-0.99; p = 0.044) per 100 fmol/µg increase in wmDNA-TG. The importance of DNA-TG as a biomarker for maintenance therapy intensity calls for novel strategies to increase DNA-TG, although its clinical value may vary by protocol backbone.

Risk factors for treatment related mortality in childhood acute lymphoblastic leukaemia.

BACKGROUND: In spite of major improvements in the cure rate of childhood acute lymphoblastic leukaemia (ALL), 2-4% of patients still die from treatment related complications. PROCEDURE: We investigated the pattern of treatment related deaths (TRDs) and possible risk factors in the NOPHO ALL-92 and ALL-2000 protocols. Fifty-five TRDs were identified among the 1,645 ALL-92 patients and 33 among the 1,090 ALL-2000 patients. RESULTS: There was no significant difference in the incidence of TRDs between the two protocols (3.4% vs. 3.2%). Five patients died before initiation of therapy (0.2%), and the overall subsequent risk of induction death and death in first complete remission (CR1) was 1.2% and 1.8%, respectively. Infections were the major cause of death comprising 72% of all cases including 9 deaths from Pseudomonas aeruginosa and 11 deaths from fungal infections. Other causes of death included bleeding or thrombosis (eight patients), tumour burden related toxicities (seven patients) and organ toxicity (seven patients). Female gender (hazard ratio (HR): 2.2, 95% confidence interval (95% CI): 1.4-3.4), high white blood cell count (≥ 200 × 10(9) /L) at diagnosis (HR: 3.5, 95% CI: 1.7-7.1), T-cell disease (HR: 1.9, 95% CI: 1.01-3.7), Down syndrome (HR: 7.3, 95% CI: 3.6-14.9) and haematopoietic stem cell transplantation in CR1 (HR: 8.0, 95% CI: 3.3-19.5) were identified as independent risk factors for TRD. CONCLUSION: Several TRDs were potentially preventable and future efforts should be directed towards patients at risk.

Bereaved parents' quality of life: resilience and professional support.

OBJECTIVES: The study aimed to compare the quality of life (QoL) among cancer-bereaved parents with a control group and explore how resilience and support from healthcare professionals associated with QoL of parents 2-8 years after the loss of a child to cancer. METHODS: This nationwide, cross-sectional survey was administered among parents (n=161) who lost their child to cancer between 2009 and 2014, compared with a matched control parent group (n=77). A study-specific questionnaire, Resilience Scale for Adults (six factors: 'Perception of self', 'Planned future', 'Social competence', 'Structured style', 'Family cohesion' and 'Social resources'), and a single-item measure of parents' QoL were included for the study. RESULTS: There was a lower QoL in both bereaved parents (mean=5.1) compared with the control parents (mean=5.8) (p<0.001). Two resilience factors, 'Perception of self' (OR=1.8, p=0.004) and 'Planned future' (OR=2.05, p<0.001), and given sufficient information during the child's last month (OR=2.63, p=0.003) were positively associated with long-term QoL in cancer-bereaved parents. CONCLUSION: The findings indicate lower QoL among both fathers and mothers 2-8 years after losing a child to cancer. The study also highlights the positive role of resilience and the importance of informational support on long-term QoL in cancer-bereaved parents. Bereavement support should be tailored for supporting individual needs.

No association between relapse hazard and thiopurine methyltransferase geno- or phenotypes in non-high risk acute lymphoblastic leukemia: a NOPHO ALL2008 sub-study.

PURPOSE: 6-mercaptopurine(6MP)/methotrexate maintenance therapy is essential to reduce relapse of childhood acute lymphoblastic leukemia (ALL). Common germline variants in TPMT cause low activity of thiopurine methyltransferase (TPMT) and higher 6MP metabolite (TGN) levels. Higher levels of TGNs incorporated into DNA (DNA-TG) and low TPMT activity have previously been associated with a lower relapse risk. We explored if TPMT geno- or phenotype was associated with DNA-TG levels and relapse rate in NOPHO ALL2008. METHODS: TPMT genotype, repeated phenotyping, and DNA-TG measurements were collected in 918 children with non-high risk ALL (NOPHO ALL2008 maintenance therapy study). Maintenance therapy started with 6MP at 50 and 75 mg/m2 for TPMT heterozygous and wildtype patients and was adjusted to a target WBC of 1.5 - 3.0 × 109/L. RESULTS: Of 918 patients, 78 (8.5%) were TPMT heterozygous and 903 had at least one TPMT measurement (total 3063). Mean TPMT activities were higher with wildtype than heterozygous TPMT (N = 752, 16.6 versus 9.6 U/mL ery., p < 0.001). The 5-year cumulative incidence of relapse was 6.4% and 6.0% for TPMT heterozygous and wildtype patients, and there was no association between genotype and relapse rate (N = 918, hazard ratio = 1.01, 95% confidence interval [CI] 0.40 - 2.54, p = 0.98). Although TPMT heterozygous patients had higher DNA-TG (N = 548, median 760.9 [interquartile range (IQR) 568.7 - 890.3] versus 492.7 [IQR 382.1 - 634.6] fmol/µg, p < 0.001), TPMT activity was not associated with relapse rate (N = 813; hazard ratio = 0.98 per one U/mL ery. increase in TPMT activity, 95% CI 0.91 - 1.06, p = 0.67). CONCLUSION: TPMT geno- and phenotype were not associated with relapse in non-high risk NOPHO ALL2008.

Hematopoietic Stem Cell Transplantation Positively Affects the Natural History of Cancer in Nijmegen Breakage Syndrome.

PURPOSE: Nijmegen breakage syndrome (NBS) is a DNA repair disorder with a high predisposition to hematologic malignancies. EXPERIMENTAL DESIGN: We describe the natural history of NBS, including cancer incidence, risk of death, and the potential effectiveness of hematopoietic stem cell transplantation (HSCT) in preventing both pathologies: malignancy and immunodeficiency. RESULTS: Among 241 patients with NBS enrolled in the study from 11 countries, 151 (63.0%) patients were diagnosed with cancer. Incidence rates for primary and secondary cancer, tumor characteristics, and risk factors affecting overall survival (OS) were estimated. The cumulative cancer incidence was 40.21% ± 3.5% and 77.78% ± 3.4% at 10 years and 20 years of follow-up, respectively. Most of the tumors n = 95 (62.9%) were non-Hodgkin lymphomas. Overall, 20 (13.2%) secondary malignancies occurred at a median age of 18 (interquartile range, 13.7-21.5) years. The probability of 20-year overall survival (OS) for the whole cohort was 44.6% ± 4.5%. Patients who developed cancer had a shorter 20-year OS than those without malignancy (29.6% vs. 86.2%; P < 10-5). A total of 49 patients with NBS underwent HSCT, including 14 patients transplanted before malignancy. Patients with NBS with diagnosed cancer who received HSCT had higher 20-year OS than those who did not (42.7% vs. 30.3%; P = 0.038, respectively). In the group of patients who underwent preemptive transplantation, only 1 patient developed cancer, which is 6.7 times lower as compared with nontransplanted patients [incidence rate ratio 0.149 (95% confidence interval, 0.138-0.162); P < 0.0001]. CONCLUSIONS: There is a beneficial effect of HSCT on the long-term survival of patients with NBS transplanted in their first complete remission of cancer.