Correction: Pre- and postdiagnosis growth failure, adult short stature, and untreated growth hormone deficiency in radiotherapy-treated long-term survivors of childhood brain tumor

[This corrects the article DOI: 10.1371/journal.pone.0274274.].

An explorative study on proteomic analyses related to inflammation and pain in children with juvenile idiopathic arthritis

BACKGROUND

Our aim was attempting to find proteins involved in the pain process and correlating with pain but not degree of inflammation in children with juvenile idiopathic arthritis (JIA), using a proteomics panel.

METHODS

A total of 87 plasma samples were collected from 51 children with JIA (51 at diagnosis in a higher disease activity state, 18 at follow-up in a lower disease activity state) and 18 healthy controls. Relative levels of 92 proteins related to a wide range of biological processes in inflammation were obtained using a proximity extension assay panel. Comparisons between children with and without JIA, in different disease categories, by juvenile disease activity score (JADAS27) and degree of pain on a visual analogue scale (VAS), were performed using parametric and non-parametric statistical methods.

RESULTS

Nineteen proteins involved in arthritic inflammation, such as interleukin 6 (IL-6) and S100 protein A12, were higher in patients with JIA than controls, seven decreased significantly during treatment, and 18 correlated significantly with JADAS27. Three proteins correlated with pain VAS scores in unadjusted analyses: the glial cell line-derived neurotrophic factor (GDNF), transforming growth factor beta, and IL-18R1. Levels of GDNF correlated significantly with pain VAS scores but not with JADAS27.

CONCLUSIONS

Plasma levels of 18 of 92 tested proteins correlated with degree of disease activity. Levels of three proteins correlated with pain, and levels of one, GDNF, originating from neural cells, correlated with pain without correlating with inflammatory degree, suggesting that it may play a role in pain in JIA. Further studies in larger cohorts are warranted.

Pre- and postdiagnosis growth failure, adult short stature, and untreated growth hormone deficiency in radiotherapy-treated long-term survivors of childhood brain tumor

PURPOSE

Growth failure is common in radiotherapy-treated long-term survivors of pediatric brain tumors, but studies on longitudinal growth in this patient group are lacking. Here, the aim was to assess the changes in growth patterns before and after brain tumor diagnosis, the adult height, and the risk factors for compromised growth. The incidence and treatment practices of growth hormone deficiency were analyzed.

METHODS

A cohort of 73 survivors of childhood brain tumor (median age 27.2 years, range 16.2 to 43.8 years) was studied after a median follow-up period of 20.4 years from diagnosis (IQR 14.9 to 22.9 years). Patients were treated in five university hospitals in Finland between 1970 and 2008. Growth curves, final height, and patient- and disease-related risk factors for compromised growth during different growth periods were analyzed. Laboratory analyses for IGF-1 and IGFBP-3 were performed at the follow-up.

RESULTS

Growth failure was evident at diagnosis, with a mean height decline of -0.6 SDS (standard deviation score) from birth (95% CI -1.15 to -0.05). Mean height SDS decline after the diagnosis was -1.09 SDS (95%CI -1.51 to -0.66). At follow-up, 37% of the study subjects (27/73) had true short stature (height < -2 SDS). The mean height deficit corrected for target height was -1.9 SDS (95% CI -1.45 to -2.40). Growth failure was associated with the age at diagnosis, corticosteroid dose, radiotherapy modality and mean dose of irradiation in the thalamic area. Low IGF-1 level (below -2.0 SDS) was found in 32% (23/72), and untreated growth hormone deficiency in 40% (29/72) of the subjects.

CONCLUSION

Longitudinal growth impairment was common in radiotherapy-treated survivors of childhood brain tumor, resulting in compromised adult height. Loss of growth potential was evident already at diagnosis and further accelerated by the treatments. At young adulthood, unrecognized growth hormone deficiency was common.

The human cathelicidin hCAP-18 in serum of children with haemato-oncological diseases

The human cathelicidin hCAP‐18 (pro‐LL‐37) is the pro‐protein of the antimicrobial peptide LL‐37. hCAP‐18 can be produced by many different cell types; bone marrow neutrophil precursors are the main source of hCAP‐18 in the circulation. Neutrophil count is used as a marker for myelopoiesis but does not always reflect neutrophil production in the bone marrow, and thus additional markers are needed. In this study, we established the reference interval of serum hCAP‐18 level in healthy children and compared serum hCAP‐18 levels between different diagnostic groups of children with haemato‐oncological diseases, at diagnosis. We found that children with diseases that impair myelopoiesis, such as acute leukaemia, aplastic anaemia, or myelodysplastic syndrome, presented with low hCAP‐18 levels, whereas patients with non‐haematological malignancies displayed serum hCAP‐18 levels in the same range as healthy children. Children with chronic myeloid leukaemia presented with high circulating levels of hCAP‐18, probably reflecting the high number of all differentiation stages of myeloid cells. We suggest that analysis of serum hCAP‐18 provides additional information regarding myelopoiesis in children with haemato‐oncological diseases, which may have future implications in assessment of myelopoiesis in clinical management.

Patient-Specific Assays Based on Whole-Genome Sequencing Data to Measure Residual Disease in Children With Acute Lymphoblastic Leukemia: A Proof of Concept Study

Risk-adapted treatment in acute lymphoblastic leukemia (ALL) relies on genetic information and measurable residual disease (MRD) monitoring. In this proof of concept study, DNA from diagnostic bone marrow (BM) of six children with ALL, without stratifying genetics or central nervous system (CNS) involvement, underwent whole-genome sequencing (WGS) to identify structural variants (SVs) in the leukemic blasts. Unique sequences generated by SVs were targeted with patient-specific droplet digital PCR (ddPCR) assays. Genomic DNA (gDNA) from BM and cell-free DNA (cfDNA) from plasma and cerebrospinal fluid (CSF) were analyzed longitudinally. WGS with 30× coverage enabled target identification in all cases. Limit of quantifiability (LoQ) and limit of detection (LoD) for the ddPCR assays (n = 15) were up to 10^-5 and 10^-6, respectively. All targets were readily detectable in a multiplexed ddPCR with minimal DNA input (1 ng of gDNA) at a 10^-1 dilution, and targets for half of the patients were also detectable at a 10^-2 dilution. The level of MRD in BM at end of induction and end of consolidation block 1 was in a comparable range between ddPCR and clinical routine methods for samples with detectable residual disease, although our approach consistently detected higher MRD values for patients with B-cell precursor ALL. Additionally, several samples with undetectable MRD by flow cytometry were MRD-positive by ddPCR. In plasma, the level of leukemic targets decreased in cfDNA over time following the MRD level detected in BM. cfDNA was successfully extracted from all diagnostic CSF samples (n = 6), and leukemic targets were detected in half of these. The results suggest that our approach to design molecular assays, together with ddPCR quantification, is a technically feasible option for accurate MRD quantification and that cfDNA may contribute valuable information regarding MRD and low-grade CNS involvement.

Does minimal central nervous system involvement in childhood acute lymphoblastic leukemia increase the risk for central nervous system toxicity?

Central nervous system (CNS) involvement in childhood acute lymphoblastic leukemia (ALL) implicates enhanced intrathecal chemotherapy, which is related to CNS toxicity. Whether CNS involvement alone contributes to CNS toxicity remains unclear. We studied the occurrence of all CNS toxicities, seizures, and posterior reversible encephalopathy syndrome (PRES) in children with ALL without enhanced intrathecal chemotherapy with CNS involvement (n = 64) or without CNS involvement (n = 256) by flow cytometry. CNS involvement increased the risk for all CNS toxicities, seizures, and PRES in univariate analysis and, after adjusting for induction therapy, for seizures (hazard ratio [HR] = 3.33; 95% confidence interval [CI]: 1.26-8.82; p = 0.016) and PRES (HR = 4.85; 95% CI: 1.71-13.75; p = 0.003).

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 (ρ_BCP-ALL  = -.17, ρ_T-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.

A somatic UBA2 variant preceded ETV6-RUNX1 in the concordant BCP-ALL of monozygotic twins

Genetic analysis of leukemic clones in monozygotic twins with concordant acute lymphoblastic leukemia (ALL) has proved a unique opportunity to gain insight into the molecular phylogenetics of leukemogenesis. Using whole-genome sequencing, we characterized constitutional and somatic single nucleotide variants/insertion-deletions (indels) and structural variants in a monozygotic twin pair with concordant ETV6-RUNX1+ B-cell precursor ALL (BCP-ALL). In addition, digital PCR (dPCR) was applied to evaluate the presence of and quantify selected somatic variants at birth, diagnosis, and remission. A shared somatic complex rearrangement involving chromosomes 11, 12, and 21 with identical fusion sequences in leukemias of both twins offered direct proof of a common clonal origin. The ETV6-RUNX1 fusion detected at diagnosis was found to originate from this complex rearrangement. A shared somatic frameshift deletion in UBA2 was also identified in diagnostic samples. In addition, each leukemia independently acquired analogous deletions of 3 genes recurrently targeted in BCP-ALLs (ETV6, ATF7IP, and RAG1/RAG2), providing evidence of a convergent clonal evolution only explained by a strong concurrent selective pressure. Quantification of the UBA2 deletion by dPCR surprisingly indicated it persisted in remission. This, for the first time to our knowledge, provided evidence of a UBA2 variant preceding the well-established initiating event ETV6-RUNX1. Further, we suggest the UBA2 deletion exerted a leukemia predisposing effect and that its essential role in Small Ubiquitin-like Modifier (SUMO) attachment (SUMOylation), regulating nearly all physiological and pathological cellular processes such as DNA-repair by nonhomologous end joining, may hold a mechanistic explanation for the predisposition.

Acute central nervous system toxicity during treatment of pediatric acute lymphoblastic leukemia: phenotypes, risk factors and genotypes

Central nervous system (CNS) toxicity is common at diagnosis and during treatment of pediatric acute lymphoblastic leukemia (ALL). We studied CNS toxicity in 1 464 children aged 1.0-17.9 years, diagnosed with ALL and treated according to the Nordic Society of Pediatric Hematology and Oncology ALL2008 protocol. Genome-wide association studies (GWAS), and a candidate single-nucleotide polymorphism (SNP; n=19) study were performed in 1 166 patients. Findings were validated in an Australian independent cohort of children with ALL (n=797) where two phenotypes were evaluated: diverse CNS toxicities (n=103) and methotrexate-related CNS toxicity (n=48). In total, 135/1 464 (9.2%) patients experienced CNS toxicity with cumulative incidence of 8.7% (95% CI: 7.31-10.20) at 12 months from diagnosis. Patients aged ≥10 years had higher risk of CNS toxicity than younger patients (16.3% vs 7.4%; p.

Impact of era of diagnosis on cause-specific late mortality among 77 423 five-year European survivors of childhood and adolescent cancer: The PanCareSurFup consortium

Late mortality of European 5-year survivors of childhood or adolescent cancer has dropped over the last 60 years, but excess mortality persists. There is little information concerning secular trends in cause-specific mortality among older European survivors. PanCareSurFup pooled data from 12 cancer registries and clinics in 11 European countries from 77 423 five-year survivors of cancer diagnosed before age 21 between 1940 and 2008 followed for an average age of 21 years and a total of 1.27 million person-years to determine their risk of death using cumulative mortality, standardized mortality ratios (SMR), absolute excess risks (AER), and multivariable proportional hazards regression analyses. At the end of follow-up 9166 survivors (11.8%) had died compared to 927 expected (SMR 9.89, 95% confidence interval [95% CI] 9.69-10.09), AER 6.47 per 1000 person-years, (95% CI 6.32-6.62). At 60 to 68 years of attained age all-cause mortality was still higher than expected (SMR = 2.41, 95% CI 1.90-3.02). Overall cumulative mortality at 25 years from diagnosis dropped from 18.4% (95% CI 16.5-20.4) to 7.3% (95% CI 6.7-8.0) over the observation period. Compared to the diagnosis period 1960 to 1969, the mortality hazard ratio declined for first neoplasms (P for trend <.0001) and for infections (P < .0001); declines in relative mortality from second neoplasms and cardiovascular causes were less pronounced (P = .1105 and P = .0829, respectively). PanCareSurFup is the largest study with the longest follow-up of late mortality among European childhood and adolescent cancer 5-year survivors, and documents significant mortality declines among European survivors into modern eras. However, continuing excess mortality highlights survivors' long-term care needs.

Health-related quality of life in long-term survivors of childhood brain tumors: a population-based cohort study

PURPOSE

Survivors of childhood brain tumors (BT) are at high risk for long-term physical and psychological sequelae. Still, knowledge about health-related quality of life (HRQL) and associated factors in this population is sparse. This study investigated HRQL and its predictors in long-term survivors of childhood BT.

METHODS

Survivors of childhood BT (mean age = 28.1 years, SD = 6.8, n = 60) underwent clinical examination and neurocognitive examination, and completed self-rating questionnaires assessing HRQL (RAND-36) and depressive symptoms (Beck Depression Inventory-II). Socio-demographic information was gathered via a questionnaire. Tumor- and treatment-related information was collected from medical records. Control group data were collected from age-matched controls (n = 146) without a history of cancer, randomly selected from the local population registry. Multiple linear regression models were used to investigate predictors of HRQL; separate models were fitted for each domain of the RAND-36.

RESULTS

Male survivors (mean age = 27.0, SD = 6.0, n = 39) reported significantly lower HRQL than male controls in the domains of physical functioning, general health, vitality, social functioning, and role limitations-emotional. Female survivors (mean age = 30.2 years, SD = 7.6, n = 21) reported comparable levels as female controls in all domains except physical functioning. A higher burden of late effects, not working/studying, being diagnosed with BT during adolescence, and reporting current depressive symptoms were significant predictors of lower HRQL.

CONCLUSION

Our results highlight that male survivors of childhood BT are at particular risk of impaired HRQL. Also, results point to the close relation between symptoms of depression and impaired HRQL in survivors of childhood BT which should be acknowledged by long-term follow-up care.

ICU Admission in Children With Acute Lymphoblastic Leukemia in Sweden: Prevalence, Outcome, and Risk Factors

OBJECTIVES

Despite progress in the treatment of childhood acute lymphoblastic leukemia, severe complications are common, and the need of supportive care is high. We explored the cumulative prevalence, clinical risk factors, and outcomes of children with acute lymphoblastic leukemia, on first-line leukemia treatment in the ICUs in Sweden.

DESIGN

A nationwide prospective register and retrospective chart review study.

SETTING

Children with acute lymphoblastic leukemia were identified, and demographic and clinical data were obtained from the Swedish Childhood Cancer Registry. Data on intensive care were collected from the Swedish Intensive Care Registry. Data on patients with registered ICU admission in the Swedish Childhood Cancer Registry were supplemented through questionnaires to the pediatric oncology centers.

PATIENTS

All 637 children 0-17.9 years old with acute lymphoblastic leukemia diagnosed between June 2008 and December 2016 in Sweden were included.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Twenty-eight percent of the children (178/637) were admitted to an ICU at least once. The Swedish Intensive Care Registry data were available for 96% of admissions (241/252). An ICU admission was associated with poor overall survival (hazard ratio, 3.25; 95% CI, 1.97-5.36; p ≤ 0.0001). ICU admissions occurred often during early treatment; 48% (85/178) were admitted to the ICU before the end of the first month of acute lymphoblastic leukemia treatment (induction therapy). Children with T-cell acute lymphoblastic leukemia or CNS leukemia had a higher risk of being admitted to the ICU in multivariable analyses, both for early admissions before the end of induction therapy and for all admissions during the study period.

CONCLUSIONS

The need for intensive care in children with acute lymphoblastic leukemia, especially for children with T cell acute lymphoblastic leukemia and CNS leukemia, is high with most admissions occurring during early treatment.

Obesity as a predictor of treatment-related toxicity in children with acute lymphoblastic leukaemia

Obesity is associated with poor outcomes in childhood acute lymphoblastic leukaemia (ALL). We explored whether severe treatment-related toxicity and treatment delays could explain this observation. This study included 1 443 children aged 2·0-17·9 years with ALL treated with the Nordic Society of Pediatric Haematology and Oncology (NOPHO) ALL2008 non-high-risk protocol. Prospective treatment-related toxicities registered every three-month interval were used. Patients were classified according to sex- and age-adjusted international childhood cut-off values, corresponding to adult body mass index: underweight, <17 kg/m² ; healthy weight, 17 to <25 kg/m² ; overweight, 25 to <30 kg/m² ; and obese, ≥30 kg/m² . Obese children had a higher incidence rate ratio (IRR) for severe toxic events {IRR: 1·55 [95% confidence interval (CI) 1·07-2·50]}, liver and kidney failures, bleeding, abdominal complication, suspected unexpected severe adverse reactions and hyperlipidaemia compared with healthy-weight children. Obese children aged ≥10 years had increased IRRs for asparaginase-related toxicities compared with healthy-weight older children: thromboses [IRR 2·87 (95% CI 1·00-8·21)] and anaphylactic reactions [IRR 7·95 (95% CI 2·15-29·37)] as well as higher risk for truncation of asparaginase [IRR 3·54 (95% CI 1·67-7·50)]. The high prevalence of toxicity and a higher risk of truncation of asparaginase may play a role in the poor prognosis of obese children aged ≥10 years with ALL.

Pattern and Prevalence of Liver Involvement in Pediatric Acute Lymphoblastic and Myeloid Leukemia at Diagnosis

OBJECTIVES

The prevalence and significance of liver involvement at diagnosis was studied in pediatric acute lymphoblastic (ALL) and myeloid leukemia (AML).

METHODS

A population based cohort of 122 pre B-ALL, 22 T-ALL and 45 AML patients was formed from the Nordic Society of Pediatric Hematology and Oncology leukemia registries (years 2005-2017). Hepatomegaly, elevated alanine aminotransferase, high INR, hypoalbuminemia and conjugated hyperbilirubinemia at diagnosis were used as markers for liver involvement. Minimal residual disease (MRD), time to relapse and overall survival (OS) were correlated with liver involvements.

RESULTS

The pattern of liver involvement was significantly different between leukemia subtypes (P = 0.025). The proportion of patients without liver abnormalities was 50.0% in AML and 44.8% in pre B-ALL and 23.5% in T-ALL patients. Hepatomegaly characterized lymphatic leukemia being present in 41.8% and 58.8% of pre B- and T-ALL patients. Liver dysfunction was most common in AML (29.5%) and least frequent in pre B-ALL (7.4%,) (P = 0.001). Conjugated hyperbilirubinemia was present in less than 5% of patients. Hepatomegaly correlated positively with age in pre B-ALL (P = 0.036) and white blood cell count (WBC) in AML (P = 0.010). Hepatic dysfunction was related with high WBC in pre B-ALL (P = 0.037) and AML (P = 0.001). Liver involvement in patients with ALL was not associated with toxicity or outcome. Patients with AML without liver involvement demonstrated superior OS.

CONCLUSIONS

Liver involvement is frequent at diagnosis in pediatric leukemia and its prevalence is related with leukemia subtype, age and WBC. In AML, but not in ALL, it associates with suboptimal prognosis.

Bone mineral density surveillance for childhood, adolescent, and young adult cancer survivors: evidence-based recommendations from the International Late Effects of Childhood Cancer Guideline Harmonization Group

Childhood, adolescent, and young adult cancer survivors are at increased risk of reduced bone mineral density. Clinical practice surveillance guidelines are important for timely diagnosis and treatment of these survivors, which could improve bone mineral density parameters and prevent fragility fractures. Discordances across current late effects guidelines necessitated international harmonisation of recommendations for bone mineral density surveillance. The International Late Effects of Childhood Cancer Guideline Harmonization Group therefore established a panel of 36 experts from ten countries, representing a range of relevant medical specialties. The evidence of risk factors for very low and low bone mineral density and fractures, surveillance modality, timing of bone mineral density surveillance, and treatment of very low and low bone mineral density were evaluated and critically appraised, and harmonised recommendations for childhood, adolescent, and young adult cancer survivors were formulated. We graded the recommendations based on the quality of evidence and balance between potential benefits and harms. Bone mineral density surveillance is recommended for survivors treated with cranial or craniospinal radiotherapy and is reasonable for survivors treated with total body irradiation. Due to insufficient evidence, no recommendation can be formulated for or against bone mineral density surveillance for survivors treated with corticosteroids. This surveillance decision should be made by the survivor and health-care provider together, after careful consideration of the potential harms and benefits and additional risk factors. We recommend to carry out bone mineral density surveillance using dual-energy x-ray absorptiometry at entry into long-term follow-up, and if normal (Z-score > -1), repeat when the survivor is aged 25 years. Between these measurements and thereafter, surveillance should be done as clinically indicated. These recommendations facilitate evidence-based care for childhood, adolescent, and young adult cancer survivors internationally.

Flow cytometric analysis of cerebrospinal fluid improves detection of leukaemic blasts in infants with acute lymphoblastic leukaemia

Infants with acute lymphoblastic leukaemia (ALL) have a high frequency of central nervous system (CNS) involvement. Flow cytometric analysis of cerebrospinal fluid (CSF) was recently demonstrated to be a sensitive method for detecting CNS involvement in childhood ALL. In the present study, CSF from 14 infants was collected at routine lumbar punctures and analysed by multicolour flow cytometry. At initial diagnosis, leukaemic blasts were detected in CSF by flow cytometry in 11 patients (78·6%) compared to seven patients (50%) by cytospin. Larger studies are needed to determine if CSF flow cytometry has prognostic value in infant ALL.

Mutational patterns and clonal evolution from diagnosis to relapse in pediatric acute lymphoblastic leukemia

The mechanisms driving clonal heterogeneity and evolution in relapsed pediatric acute lymphoblastic leukemia (ALL) are not fully understood. We performed whole genome sequencing of samples collected at diagnosis, relapse(s) and remission from 29 Nordic patients. Somatic point mutations and large-scale structural variants were called using individually matched remission samples as controls, and allelic expression of the mutations was assessed in ALL cells using RNA-sequencing. We observed an increased burden of somatic mutations at relapse, compared to diagnosis, and at second relapse compared to first relapse. In addition to 29 known ALL driver genes, of which nine genes carried recurrent protein-coding mutations in our sample set, we identified putative non-protein coding mutations in regulatory regions of seven additional genes that have not previously been described in ALL. Cluster analysis of hundreds of somatic mutations per sample revealed three distinct evolutionary trajectories during ALL progression from diagnosis to relapse. The evolutionary trajectories provide insight into the mutational mechanisms leading relapse in ALL and could offer biomarkers for improved risk prediction in individual patients.

Skeletal adverse events in childhood cancer survivors: An Adult Life after Childhood Cancer in Scandinavia cohort study

The dynamic growth of the skeleton during childhood and adolescence renders it vulnerable to adverse effects of cancer treatment. The lifetime risk and patterns of skeletal morbidity have not been described in a population-based cohort of childhood cancer survivors. A cohort of 26 334 1-year cancer survivors diagnosed before 20 years of age was identified from the national cancer registries of Denmark, Finland, Iceland and Sweden as well as a cohort of 127 531 age- and sex-matched comparison subjects randomly selected from the national population registries in each country. The two cohorts were linked with data from the national hospital registries and the observed numbers of first-time hospital admissions for adverse skeletal outcomes among childhood cancer survivors were compared to the expected numbers derived from the comparison cohort. In total, 1987 childhood cancer survivors had at least one hospital admission with a skeletal adverse event as discharge diagnosis, yielding a rate ratio (RR) of 1.35 (95% confidence interval, 1.29-1.42). Among the survivors, we observed an increased risk for osteonecrosis with a RR of 25.9 (15.0-44.5), osteoporosis, RR 4.53 (3.28-6.27), fractures, RR 1.27 (1.20-1.34), osteochondropathies, RR 1.57 (1.28-1.92) and osteoarthrosis, RR 1.48 (1.28-1.72). The hospitalization risk for any skeletal adverse event was higher among survivors up to the age of 60 years, but the lifetime pattern was different for each type of skeletal adverse event. Understanding the different lifetime patterns and identification of high-risk groups is crucial for developing strategies to optimize skeletal health in childhood cancer survivors.

Severe toxicity free survival: physician-derived definitions of unacceptable long-term toxicities following acute lymphocytic leukaemia

5-year overall survival rates have surpassed 90% for childhood acute lymphocytic leukaemia, but survivors are at risk for permanent health sequelae. Although event-free survival appropriately represents the outcome for cancers with poor overall survival, this metric is inadequate when cure rates are high but challenged by serious, persistent complications. Accordingly, a group of experts in paediatric haematology-oncology, representative of 17 international acute lymphocytic leukaemia study groups, launched an initiative to construct a measure, designated severe toxicity-free survival (STFS), to quantify the occurrence of physician-prioritised toxicities to be integrated with standard cancer outcome reporting. Five generic inclusion criteria (not present before cancer diagnosis, symptomatic, objectifiable, of unacceptable severity, permanent, or requiring unacceptable treatments) were used to assess 855 health conditions, which resulted in inclusion of 21 severe toxicities. Consensus definitions were reached through a modified Delphi process supplemented by two additional plenary meetings. The 21 severe toxicities include severe adverse health conditions that substantially affect activities of daily living and are refractory to therapy (eg, refractory seizures), are without therapeutic options (eg, blindness), or require substantially invasive treatment (eg, cardiac transplantation). Incorporation of STFS assessment into clinical trials has the potential to improve and diversify treatment strategies, focusing not only on traditional outcome events and overall survival but also the frequencies of the most severe toxicities. The two major aims of this Review were to: prioritise and define unacceptable long-term toxicity for patients with childhood acute lymphocytic leukaemia, and define how these toxicities should be combined into a composite quantity to be integrated with other reported outcomes. Although STFS quantifies the clinically unacceptable health tradeoff for cure using childhood acute lymphocytic leukaemia as a model disease, the prioritised severe toxicities are based on generic considerations of relevance to any other cancer diagnosis and age group.

Help-seeking behaviour and attitudes towards internet-administered psychological support among adolescent and young adults previously treated for cancer during childhood: protocol for a survey and embedded qualitative interview study in Sweden

INTRODUCTION

A subgroup of adolescent and young adult childhood cancer survivors (AYACCS) are at increased risk of psychological distress. Despite this, AYACCS experience difficulties accessing psychological support. E-mental health (e-MH) may offer a solution to reduce this treatment gap. However, research examining e-MH for AYACCS has experienced difficulties with recruitment, retention and adherence. Such difficulties may relate to: (1) help-seeking behaviour and/or (2) e-MH acceptability. The overall study aims are to: (1) examine potential associations between health service use factors, informed by Andersen's behavioural model of health services use, and help-seeking behaviour; (2) examine attitudes towards e-MH interventions; and (3) explore perceived need for mental health support; past experience of receiving mental health support; preferences for support; and barriers and facilitators to help-seeking.

METHODS AND ANALYSIS

An online and paper-based cross-sectional self-report survey (98 items) and embedded qualitative interview study across Sweden, with a target sample size of n=365. Participants are aged 16-39 years, diagnosed with cancer when 0-18 years and have completed successful cancer treatment. The survey examines sociodemographic and clinical characteristics, actual help-seeking behaviour, attitudes towards e-MH, stigma of mental illness, mental health literacy, social support and current symptoms of depression, anxiety, and stress. Survey respondents with past and/or current experience of mental health difficulties are invited into the qualitative interview study to explore: (1) perceived need for mental health support; (2) past experience of receiving mental health support; (3) preferences for support; and (4) barriers and facilitators to help-seeking. Potential associations between health service use factors and help-seeking behaviour are examined using univariable and multivariable logistic regressions. Qualitative interviews are analysed using content analysis.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from the Swedish Ethical Review Authority (Dnr: 2020-06271). Results will be disseminated in scientific publications and academic conference presentations.

TRIAL REGISTRATION NUMBER

ISRCTN70570236.

QOL-12. CLINICAL SIGNIFICANCE OF RADIATION-INDUCED CEREBROVASULAR DISEASE IN CHILDHOOD BRAIN TUMOR SURVIVORS

BACKGROUND

Childhood brain tumor survivors have a high risk of early cerebrovascular disease, but currently its clinical significance is unknown.

METHODS

In a nation-wide study, we investigated 68 childhood brain tumor survivors treated with radiotherapy by using magnetic resonance imaging (MRI) and neuropsychological examination after median follow-up time of 20.6 years (range 5.0 – 33.1 years) since radiotherapy. Associations between imaging markers of cerebrovascular disease, white matter hyperintensities and the results of neuropsychological examination were investigated.

RESULTS

Majority (65 %) of the survivors was diagnosed with cerebrovascular disease at median age of 27.1 years (range16.2 – 43.8 years). The presence of imaging markers of cerebrovascular disease or white matter hyperintensities was associated with poorer performance in verbal (VIQ) and performance (PIQ) intelligent quotient, working and semantic memory, executive functions, visuospatial ability, and immediate and general auditive memory (P < 0.05). Survivors with microbleeds performed worse in PIQ, processing speed, executive functions, and visuospatial ability (P <0.05). Lacunar infarcts were associated with difficulties in visuospatial ability (P <0.05). Survivors with white matter hyperintensities in MRI had higher impairment of working and semantic memory, visuospatial ability, and general auditive memory (P < 0.05). Cerebrovascular and small-vessel disease burden associated with poorer neurocognitive performance.

CONCLUSION

The imaging markers of cerebrovascular disease and white matter hyperintensities were related to poorer cognitive performance in radiation-treated long-term survivors of childhood brain tumor. Longitudinal studies are urgently needed to investigate how cerebrovascular disease and related cognitive impairment progress in the survivors.

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.

Seizures during treatment of childhood acute lymphoblastic leukemia: A population-based cohort study

BACKGROUND

Seizures are common in children with acute lymphoblastic leukemia (ALL). As ALL survival rates are improving, the challenge to minimize treatment related side effects and late sequelae rises. Here, we studied the frequency, timing, etiology and risk factors of seizures in ALL patients.

METHODS

The study included children aged 1-17.9 years at diagnosis of B-cell-precursor and T cell ALL who were treated according to the Nordic Society of Pediatric Hematology and Oncology (NOPHO) ALL2008 protocol between 2008 and 2015. Detailed patient data were acquired from the NOPHO ALL2008 registry and by review of medical records.

RESULTS

Seizures occurred in 81/1464 (5.5%) patients. The cumulative incidence of seizures at one months was 1.7% (95% CI: 1.2-2.5) and at one year 5.3% (95% CI 4.2-6.5%). Patients aged 10-17.9 years, those with T cell immunophenotype, CNS involvement, or high-risk induction with dexamethasone had higher risk for seizures in univariable analyses. Only age remained a risk factor in multivariable analyses (the cumulative incidence of seizures for patients 10-17.9 years old at one year was 9.0% (95% CI: 6.2-12.9)). Of the 81 patients with seizures, 43 had posterior reversible encephalopathy syndrome (PRES), 15 had isolated seizures, nine had sinus venous thrombosis (SVT), three had stroke-like syndrome, and 11 had other neurotoxicities. Epilepsy diagnosis was reported in totally 11 ALL survivors at last follow up.

CONCLUSION

Seizures are relatively common in ALL patients and occur most often in patients with PRES, SVT, or as an isolated symptom. Older children have higher risk of seizures.

Vitamin D status in children with leukemia, its predictors, and association with outcome

BACKGROUND

Children and adolescents with leukemia are potentially at high risk of vitamin D inadequacy, which may have clinical relevance for skeletal morbidity, infections, and cancer outcome. This study aimed to evaluate vitamin D status at the time of diagnosis to investigate its predictors and association with overall survival in children with leukemia.

PROCEDURE

We included all 295 children and adolescents diagnosed with leukemia at our institution between 1990 and 2016 who had available serum sample from the time of diagnosis. We analyzed serum 25-hydroxyvitamin D and parathyroid hormone levels and correlated them with clinical data.

RESULTS

The 25-hydroxyvitamin D level was deficient (< 25 nmol/L), insufficient (25-50 nmol/L), sufficient (50-75 nmol/L), and optimal (> 75 nmol/L) in 6.4%, 26.8%, 39.7%, and 27.1% of the children, respectively. Older age and a more recent time of sampling (calendar year) predicted lower 25-hydroxyvitamin D level. In preschool children (age ≤6 years), lower 25-hydroxyvitamin D level was also associated with acute myeloid leukemia, and a 25-hydroxyvitamin D level < 50 nmol/L was associated with inferior overall survival. In school-aged children (age > 6 years), the 25-hydroxyvitamin D level showed significant seasonal variation.

CONCLUSION

It remains unclear whether vitamin D supplementation in pediatric leukemia patients will improve outcome.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Asparaginase-Associated Pancreatitis in Acute Lymphoblastic Leukemia: Results From the NOPHO ALL2008 Treatment of Patients 1-45 Years of Age

PURPOSE

Asparaginase-associated pancreatitis (AAP) is common in patients with acute lymphoblastic leukemia (ALL), but risk differences across age groups both in relation to first-time AAP and after asparaginase re-exposure have not been explored.

PATIENTS AND METHODS

We prospectively registered AAP (n = 168) during treatment of 2,448 consecutive ALL patients aged 1.0-45.9 years diagnosed from July 2008 to October 2018 and treated according to the Nordic Society of Pediatric Hematology and Oncology (NOPHO) ALL2008 protocol.

RESULTS

Compared with patients aged 1.0-9.9 years, adjusted AAP hazard ratios (HRa) were associated with higher age with almost identical HRa (1.6; 95% CI, 1.1 to 2.3; P = .02) for adolescents (10.0-17.9 years) and adults (18.0-45.9 years). The day 280 cumulative incidences of AAP were 7.0% for children (1.0-9.9 years: 95% CI, 5.4 to 8.6), 10.1% for adolescents (10.0 to 17.9 years: 95% CI, 7.0 to 13.3), and 11.0% for adults (18.0-45.9 years: 95% CI, 7.1 to 14.9; P = .03). Adolescents had increased odds of both acute (odds ratio [OR], 5.2; 95% CI, 2.1 to 13.2; P = .0005) and persisting complications (OR, 6.7; 95% CI, 2.4 to 18.4; P = .0002) compared with children (1.0-9.9 years), whereas adults had increased odds of only persisting complications (OR, 4.1; 95% CI, 1.4 to 11.8; P = .01). Fifteen of 34 asparaginase-rechallenged patients developed a second AAP. Asparaginase was truncated in 17/21 patients with AAP who subsequently developed leukemic relapse, but neither AAP nor the asparaginase truncation was associated with increased risk of relapse.

CONCLUSION

Older children and adults had similar AAP risk, whereas morbidity was most pronounced among adolescents. Asparaginase re-exposure should be considered only for patients with an anticipated high risk of leukemic relapse, because multiple studies strongly indicate that reduction of asparaginase treatment intensity increases the risk of relapse.

Overexpression of chromatin remodeling and tyrosine kinase genes in iAMP21-positive acute lymphoblastic leukemia

Intrachromosomal amplification of chromosome 21 (iAMP21) is a cytogenetic subtype associated with relapse and poor prognosis in pediatric B-cell precursor acute lymphoblastic leukemia (BCP ALL). The biology behind the high relapse risk is unknown and the aim of this study was to further characterize the genomic and transcriptional landscape of iAMP21. Using DNA arrays and sequencing, we could identify rearrangements and aberrations characteristic for iAMP21. RNA sequencing revealed that only half of the genes in the minimal region of amplification (20/45) were differentially expressed in iAMP21. Among them were the top overexpressed genes (p < 0.001) in iAMP21 vs. BCP ALL without iAMP21 and three candidate genes could be identified, the tyrosine kinase gene DYRK1A and chromatin remodeling genes CHAF1B and SON. While overexpression of DYRK1A and CHAF1B is associated with poor prognosis in malignant diseases including myeloid leukemia, this is the first study to show significant correlation with iAMP21-positive ALL.

Predisposition to childhood acute lymphoblastic leukemia caused by a constitutional translocation disrupting ETV6

Pathogenic germline variants in ETV6 have been associated with familial predisposition to thrombocytopenia and hematological malignancies, predominantly childhood B-cell precursor acute lymphoblastic leukemia (BCP-ALL). In addition, overrepresentation of a high hyperdiploid subtype and older age at diagnosis have been reported among sporadic BCP-ALL cases with germline variants in ETV6 We studied a family with 2 second-degree relatives who developed childhood high hyperdiploid BCP-ALL at ages 8 and 12 years, respectively. A constitutional balanced reciprocal translocation t(12;14)(p13.2;q23.1) was discovered in both patients by routine karyotyping at diagnosis and, subsequently, in 7 healthy family members who had not experienced hematological malignancies. No carriers had thrombocytopenia. Whole-genome sequencing confirmed the translocation, resulting in 2 actively transcribed but nonfunctional fusion genes, causing heterozygous loss and consequently monoallelic expression of ETV6 Whole-genome sequencing analysis of the affected female subjects' leukemia excluded additional somatic aberrations in ETV6 and RTN1 as well as shared somatic variants in other genes. Expression studies, performed to confirm decreased expression of ETV6, were not conclusive. We suggest that germline aberrations resulting in monoallelic expression of ETV6 contribute to leukemia susceptibility, whereas more severe functional deficiency of ETV6 is required for developing THC5. To our knowledge, this report is the first of a constitutional translocation disrupting ETV6 causing predisposition to childhood ALL.

Prevalence of chronic hepatitis C virus infection among childhood cancer survivors in Stockholm, Sweden

Background: Childhood cancer survivors treated before 1992, when blood donor screening for hepatitis C virus (HCV) infection was introduced, are at risk of transfusion-transmitted HCV infection. A national HCV screening campaign targeting blood transfusion recipients was launched in Sweden in 2007-2010. The aims of this study were to, among adult childhood cancer survivors in Stockholm County, investigate the prevalence of HCV infection, the natural course of infection, treatment outcome and anti-HCV testing frequency before, during and after the screening campaign and finally to actively screen the untested ones. Material and Methods: This was a combined retrospective register based and prospective screening study of adult childhood cancer survivors (n = 686) treated for malignancy in Stockholm before 1992. In the first part, we investigated the prevalence of HCV infection and previous anti-HCV testing, and in the second part, we actively traced and HCV-screened the remaining untested cohort living in Stockholm. Analysis of previous documented anti-HCV tests in medical records, laboratory records, and the national communicable disease registry was performed. In the second part, 231 presumably untested individuals were contacted by mail and offered an anti-HCV test. The natural course of HCV infection and treatment outcome was analyzed for those found to be chronically infected. Results: In total, 235 patients were tested and 11 were HCV-RNA positive. The overall prevalence of chronic HCV infection among the tested childhood cancer survivors was thus 4.7% (95% CI = 2.6-8.2%), which is almost 10 times higher than the national prevalence of 0.5%. Only 12% of the Stockholm cohort were tested during the screening campaign in 2007-2010, while the test uptake using active tracing screening within this study was 40% (p < .001). Conclusion: With today's effective treatment options, active tracing and HCV screening of childhood cancer survivors are recommended.

Posterior reversible encephalopathy syndrome in children with acute lymphoblastic leukemia: Clinical characteristics, risk factors, course, and outcome of disease

BACKGROUND

Posterior reversible encephalopathy syndrome (PRES) is a distinct entity with incompletely known predisposing factors. The aim of this study is to describe the incidence, risk factors, clinical course, and outcome of PRES in childhood acute lymphoblastic leukemia (ALL).

PROCEDURE

Patients aged 1.0 to 17.9 years diagnosed with ALL from July 2008 to December 2015 and treated according to the Nordic Society of Pediatric Hematology and Oncology (NOPHO) ALL2008 protocol were included. Patients with PRES were identified in the prospective NOPHO leukemia toxicity registry, and clinical data were collected from the medical records.

RESULTS

The study group included 1378 patients, of whom 52 met the criteria for PRES. The cumulative incidence of PRES at one month was 1.7% (95% CI, 1.1-2.5) and at one year 3.7% (95% CI, 2.9-4.9). Older age (hazard ratios [HR] for each one-year increase in age 1.1; 95% CI, 1.0-1.2, P = 0.001) and T-cell immunophenotype (HR, 2.9; 95% CI, 1.6-5.3, P = 0.0005) were associated with PRES. Central nervous system (CNS) involvement (odds ratios [OR] = 2.8; 95% CI, 1.2-6.5, P = 0.015) was associated with early PRES and high-risk block treatment (HR = 2.63; 95% CI, 1.1-6.4, P = 0.033) with late PRES. At follow-up of the PRES patients, seven patients had epilepsy and seven had neurocognitive difficulties.

CONCLUSION

PRES is a neurotoxicity in the treatment of childhood ALL with both acute and long-term morbidity. Older age, T-cell leukemia, CNS involvement and high-risk block treatment are risk factors for PRES.

The radiological and clinical follow-up of osteonecrosis in cancer patients

BACKGROUND

In patients with cancer, osteonecrosis (ON) lesions can affect multiple sites throughout the skeleton, including the long and short bones and the joints. The aims of this study were to explore the natural course of ON in patients treated for cancer by using radiological classification suitable for multisite ON lesions and to assess correlations between the ON grade and surgical procedures.

MATERIAL AND METHODS

Data were retrieved from hospital databases on 233 ON lesions in 54 patients (aged 2-73 years at cancer diagnosis; mean age: 25 years). ONs were graded according to the Niinimäki classification, based on magnetic resonance images. Medical records were reviewed to identify surgical procedures.

RESULTS

A total of 14 different ON sites were detected; the hip was the most common site (n = 51), followed by the femur (n = 45), tibia (n = 41) and knee (n = 37). Among the 233 ON lesions, 78.1% did not require surgical procedures. The remaining lesions required total joint arthroplasty (TJA; 40/233, 17.2%), core decompression (3.4%) and arthroscopy (1.3%). Most TJAs (33/40, 82.5%) were performed on the hip. ONs of the knee required TJAs only once; grade 3 knee ONs frequently healed (58%, 11/19). None of the diaphyseal or metaphyseal (grade 1-2) ONs of the long bones required surgery, and no fractures of those bones were identified.

CONCLUSIONS

In conclusion, the natural history of ONs varied by the grade and site. Based on our findings, we would not recommend routine radiological follow-ups for grades 1-2 ON lesions that do not affect the joints, because the clinical consequences of those lesions appear to be minimal, although pain relief would be warranted. In contrast, joint deformations (grade 5) require surgery; therefore, intervention studies should focus on grades 3-4 ON lesions.

Early central line-associated blood stream infections in children with cancer pose a risk for premature catheter removal

AIM

This study examined the clinical characteristics of central line-associated blood stream infections occurring within 30 days after insertion versus later infections in paediatric cancer patients and the subsequent risk for premature catheter removal.

METHODS

This was a retrospective study of children aged 0-18 years who were diagnosed with cancer from 2013 to 2014 at the Astrid Lindgren Children Hospital, Sweden. Clinical and microbiology data for each patient were collected for 365 days after the central venous catheter (CVC) was inserted.

RESULTS

During the study period, 154 children received a CVC. The overall incidence of central line associated blood stream infections was 2.0 per 1000 catheter days. A total of 108 infectious episodes were identified in 44/154 (29%) patients. Of those, 15/44 children (29%) had an early infection within 30 days and alpha-haemolytic Streptococci and coagulase-negative Staphylococci dominated. Children with early infections were more likely to have a haematological malignancy and to need premature removal of the CVC due to repeated infections.

CONCLUSION

We observed a high prevalence of early CVC associated blood stream infection mainly in patients with haematological malignancies. Our study highlights the importance of preventive measures in reducing infections in paediatric cancer patients.

Asparaginase treatment in infants with acute lymphoblastic leukemia; pharmacokinetics and asparaginase hypersensitivity in Interfant-06

Acute lymphoblastic leukemia (ALL) is a rare disease in infants. Asparaginase is an essential part of the treatment, and there Acute is a need to evaluate the efficiency and safety of this drug in this age group. We evaluated the pharmacokinetics of intramuscularly administered native E. coli asparaginase (Asparaginase Medac^®) and PEG-asparaginase (Oncaspar^®) as well as hypersensitivity reactions during treatment in Interfant-06 ( www.clinicaltrials.gov : NCT01025804). All patients without hypersensitivity had sufficiently high enzyme activity levels during treatment with both preparations. Patients with hypersensitivity reactions during treatment, characterized by the presence of either or not of clinical symptoms and no measurable enzyme activity, received ineffective therapy. For optimization of the bad prognosis in infant ALL, therapeutic drug monitoring should be performed for identification of patients who should be switched to a different asparaginase preparation because of inactivation of the drug.

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.

Comparing osteonecrosis clinical phenotype, timing, and risk factors in children and young adults treated for acute lymphoblastic leukemia

BACKGROUND

Treatment-related osteonecrosis (ON) is a serious complication of treatment of acute lymphoblastic leukemia (ALL).

PROCEDURE

This study included 1,489 patients with ALL, aged 1-45 years, treated according to the Nordic Society of Paediatric Haematology and Oncology ALL2008 protocol, using alternate-week dexamethasone during delayed intensification, with prospective registration of symptomatic ON. We aimed at comparing risk factors, timing, and clinical characteristics of ON in children and young adults.

RESULTS

ON was diagnosed in 67 patients, yielding a 5-year cumulative incidence of 6.3%, but 28% in female adolescents. Median age at ALL diagnosis was 12.1 years and 14.9 years for females and males, respectively. At ON diagnosis, 59 patients had bone pain (91%) and 30 (46%) had multiple-joint involvement. The median interval between ALL and ON diagnosis was significantly shorter in children aged 1.0-9.9 years (0.7 years [range: 0.2-2.1]) compared with adolescents (1.8 years [range: 0.3-3.7, P < 0.001]) and adults (2.1 years [range: 0.4-5.3, P = 0.001]). Female sex was a risk factor in adolescent patients (hazard ratio [HR] = 2.1, 95% confidence interval [CI]: 1.1-4.2) but not in children aged 1.1-9.9 years (HR = 2.4, 95% CI: 0.9-6.2, P = 0.08) or adults aged 19-45 years (HR = 1.1, 95% CI: 0.3-4.0). Age above 10 years at ALL diagnosis (odds ratio [OR] = 3.7, P = 0.026) and multiple joints affected at ON diagnosis (OR = 3.4, P = 0.027) were risk factors for developing severe ON.

CONCLUSION

We provide a detailed phenotype of patients with ALL with symptomatic ON, including description of risk factors and timing of ON across age groups. This awareness is essential in exploring measures to prevent development of ON.

NT5C2 germline variants alter thiopurine metabolism and are associated with acquired NT5C2 relapse mutations in childhood acute lymphoblastic leukaemia

The antileukaemic drug 6-mercaptopurine is converted into thioguanine nucleotides (TGN) and incorporated into DNA (DNA-TG), the active end metabolite. In a series of genome-wide association studies, we analysed time-weighted means (_wm) of erythrocyte concentrations of TGN (Ery-TGN) and DNA-TG in 1009 patients undergoing maintenance therapy for acute lymphoblastic leukaemia (ALL). In discovery analyses (454 patients), the propensity for DNA-TG incorporation (_wmDNA-TG/_wmEry-TGN ratio) was significantly associated with three intronic SNPs in NT5C2 (top hit: rs72846714; P = 2.09 × 10^-10, minor allele frequency 15%). In validation analyses (555 patients), this association remained significant during both early and late maintenance therapy (P = 8.4 × 10^-6 and 1.3 × 10^-3, respectively). The association was mostly driven by differences in _wmEry-TGN, but in regression analyses adjusted for _wmEry-TGN (P < 0.0001), rs72846714-A genotype was also associated with a higher _wmDNA-TG (P = 0.029). Targeted sequencing of NT5C2 did not identify any missense variants associated with rs72846714 or _wmEry-TGN/_wmDNA-TG. rs72846714 was not associated with relapse risk, but in a separate cohort of 180 children with relapsed ALL, rs72846714-A genotype was associated with increased occurrence of relapse-specific NT5C2 gain-of-function mutations that reduce cytosol TGN levels (P = 0.03). These observations highlight the impact of both germline and acquired mutations in drug metabolism and disease trajectory.

Novel non-neutral mitochondrial DNA mutations found in childhood acute lymphoblastic leukemia

Mitochondria produce adenosine triphosphate (ATP) for energy requirements via the mitochondrial oxidative phosphorylation (OXPHOS) system. One of the hallmarks of cancer is the energy shift toward glycolysis. Low OXPHOS activity and increased glycolysis are associated with aggressive types of cancer. Mitochondria have their own genome (mitochondrial DNA [mtDNA]) encoding for 13 essential subunits of the OXPHOS enzyme complexes. We studied mtDNA in childhood acute lymphoblastic leukemia (ALL) to detect potential pathogenic mutations in OXPHOS complexes. The whole mtDNA from blood and bone marrow samples at diagnosis and follow-up from 36 ALL patients were analyzed. Novel or previously described pathogenic mtDNA mutations were identified in 8 out of 36 patients. Six out of these 8 patients had died from ALL. Five out of 36 patients had an identified poor prognosis genetic marker, and 4 of these patients had mtDNA mutations. Missense or nonsense mtDNA mutations were detected in the genes encoding subunits of OXPHOS complexes, as follows: MT-ND1, MT-ND2, MT-ND4L and MT-ND6 of complex I; MT-CO3 of complex IV; and MT-ATP6 and MT-ATP8 of complex V. We discovered mtDNA mutations in childhood ALL supporting the hypothesis that non-neutral variants in mtDNA affecting the OXPHOS function may be related to leukemic clones.

Presenting features and imaging in childhood acute myeloid leukemia with central nervous system involvement

Central nervous system (CNS) involvement in childhood acute myeloid leukemia (AML) can manifest as leukemic cells in the cerebrospinal fluid, a solid CNS tumor, or as neurological symptoms. We evaluated the presenting symptoms and neuroimaging findings in 33 of 34 children with AML and CNS involvement at diagnosis in the period 2000-2012 in Sweden, Finland, and Denmark. Imaging was performed in 22 patients, of whom 16 had CNS-related symptoms. Seven patients, including all but two with facial palsy, had mastoid cell opacification, considered an incidental finding. The frequent involvement of the mastoid bone with facial palsy warrants evaluation in larger series.

Compulsory military service as a measure of later physical and cognitive performance in male survivors of childhood cancer

BACKGROUND

Compromised physical fitness and cognitive difficulties have been reported as late effects of cancer treatment during childhood. To assess this issue, the military rankings of cancer survivors in medical checkups at call-up, and conscripts' physical and cognitive performance during the first weeks of compulsory military education were compared to those of matched population controls without a history of cancer.

MATERIAL AND METHODS

A total of 1680 male patients born between 1960 and 1992 with a malignancy diagnosed before the age of 16 who were alive at the call-up age (18 years) were identified using the Finnish Cancer Registry, and five age, sex and place of residence matched controls for each patient using the Population Register Centre. Data on military service were gathered from Finnish Defense Forces. A conditional logistic regression analysis, the GEE-method with the cumulative logit link function, the chi-square test, the chi-square test for trend and a one-way analysis of variance were used in different analyses.

RESULTS

Cancer survivors were exempted from military service more often than the controls (p < .001). The fit-for-service frequency was highest for survivors of kidney tumors (68%) and lowest after irradiated brain tumors (19%). In service, the results of the 12-min running test were poorer than those of controls for leukemia/non-Hodgkin lymphoma (p = .03) and brain tumor (p = .01) survivors. Interestingly, the standing long-jump test was the only muscle test for which survivor groups performed worse than controls. Performance on cognitive tests only differed from controls in brain tumor survivors.

CONCLUSIONS

Exemption from service is still common under the current guidelines, but fit-for-service survivors do well in military education. These results can be used for reassuring survivors that completion of military service is possible for those fulfilling the national general guidelines for military fitness.

Early presentation of osteonecrosis in acute lymphoblastic leukemia: Two children from the Nordic and Baltic cohort

Osteonecrosis (ON) is usually considered treatment related in patients with acute lymphoblastic leukemia (ALL). We report two patients with presentation of ON at the time of ALL diagnosis. Both were females and diagnosed with ALL at age 8 and 14 years. In the latter, some symptoms and radiologically verified ON in both knees were still present after the end of ALL therapy. No pediatric patients have previously been reported with ON presenting before initiation of ALL therapy.

Hypertriglyceridemia during asparaginase treatment in children with acute lymphoblastic leukemia correlates with antithrombin activity in adolescents

BACKGROUND

Asparaginase (ASP) is a cornerstone in the treatment of acute lymphoblastic leukemia (ALL). It is also known for its ability to cause side effects, such as allergy and pancreatitis, as well as lipid and coagulation disturbances. The most important laboratory abnormalities are hypertriglyceridemia (HTG) and low antithrombin (AT). HTG is usually considered to be transient and benign in children with ALL, whereas low AT activity predisposes to thrombosis. Studies on the incidence and significance of HTG in children with ALL are scarce, and their findings have not always been congruent. We investigated the incidence and significance of ASP-related HTG, defined as triglyceride values more than five times the upper normal limit, in children with ALL.

PROCEDURE

We analyzed the laboratory and clinical data of children diagnosed with ALL at the Karolinska Hospital, Stockholm, Sweden, from July 2008 to December 2014. Triglyceride and AT values were measured before each injection of pegylated ASP.

RESULTS

The study group comprised of 92 patients, aged 1-17.9 years at diagnosis (median 4.8 years), almost half (42/92, 46%) of whom had HTG. A significant negative correlation between triglyceride and AT values was observed in those aged over 10 years (P = 0.0002). No significant correlation was found between HTG and thrombosis, osteonecrosis, or pancreatitis.

CONCLUSIONS

Although common, ASP-associated HTG was not associated with other ASP-related toxicities. HTG correlated with decreased AT activity in older children, which may explain previous association between HTG and thrombosis. Larger studies are of interest with regard to establishing guidelines for HGT management.

Delayed elimination of high-dose methotrexate and use of carboxypeptidase G2 in pediatric patients during treatment for acute lymphoblastic leukemia

BACKGROUND

Carboxypeptidase G2 (CPDG₂ ) can be used as rescue treatment in cases of delayed methotrexate elimination (DME) and Mtx-induced nephrotoxicity.

PROCEDURE

Between July 2008 and December 2014, all children (1.0-17.9 years) in the Nordic countries diagnosed with Philadelphia chromosome negative acute lymphoblastic leukemia (ALL) were treated according to the Nordic Organization for Pediatric Hematology and Oncology (NOPHO) ALL 2008 protocol, including administration of six to eight high-dose (5 g/m² /24 hr) Mtx (HDMtx) courses. The protocol includes recommendations for CPDG₂ administration in cases of DME (clinicaltrials.gov NCT01305655).

RESULTS

Forty-seven of the 1,286 children (3.6%) received CPDG₂ during 50 HDMtx courses at a median dose of 50 IU/kg. In 49% of the cases, CPDG₂ was used during the first HDMtx course. Within a median of 6 hr from CPDG₂ administration, the Mtx concentration decreased by 75% when measured with immune-based methods, and by 100% when measured with high-performance liquid chromatography. The median time from the start of Mtx infusion to plasma levels ≤ 0.2 μM was 228 hr (range: 48-438). The maximum increase in plasma creatinine was 375% (range: 100-1,310). Creatinine peaked after a median of 48 hr (range: 36-86). Mtx elimination time was shorter in patients with body surface area < 1 m² (median 198.5 vs. 257 hr; P = 0.004) and was inversely correlated to the maximum creatinine increase (209 vs. 258 hr; P = 0.034). All patients normalized their renal function as measured with s-creatinine.

CONCLUSIONS

CPDG₂ administration is highly effective as rescue in case of delayed Mtx clearance. Subsequent HDMtx courses could be administered without events in most of the patients.

Role of neuroimaging in children with acute lymphoblastic leukemia and central nervous system involvement at diagnosis

BACKGROUND

Each year approximately 200 children and adolescents are diagnosed with acute lymphoblastic leukemia (ALL) in the five Nordic countries, and 3% of these have central nervous system (CNS) involvement confirmed by leukemic cells in the cerebrospinal fluid (CSF) or neurological symptoms. We sought to determine the significance of neuraxis imaging in such patients.

PROCEDURE

Magnetic resonance images of children aged 1-17.9 with CNS leukemia at diagnosis of ALL were centrally reviewed and clinical data were retrieved from the medical records and the Nordic leukemia registry. Patients were diagnosed in the period 2000-2012 in Sweden, Finland, or Denmark.

RESULTS

The cohort comprised 1,877 patients, and 66 (3.5%) had CNS involvement. Forty-five percent (30/66) had CNS related symptoms. Symptoms included vomiting, facial palsy, headache, visual symptoms, and impaired hearing. CNS imaging was performed in 32 of 66 children (48%), and confirmed CNS involvement in 6 of 21 patients with symptoms (29%) and 5 of 11 (45%) without (P = 0.44). There was no difference in the overall survival between CNS-positive patients with and without signs of leukemic involvement by imaging (P = 0.53).

CONCLUSIONS

Radiological imaging of asymptomatic children with CNS leukemia at diagnosis lacks clinical importance, but may be useful in patients with cranial nerve symptoms and negative CSF, as well as for follow-up. Imaging of symptomatic patients is warranted in order to exclude other causes underlying the symptoms.

Leukemic blasts are present at low levels in spinal fluid in one-third of childhood acute lymphoblastic leukemia cases

BACKGROUND

Central nervous system (CNS) involvement is associated with relapse in childhood acute lymphoblastic leukemia (ALL) and is a diagnostic challenge.

PROCEDURE

In a Nordic/Baltic prospective study, we assessed centralized flow cytometry (FCM) of locally fixed cerebrospinal fluid (CSF) samples versus local conventional cytospin-based cytology (CC) for detecting leukemic cells and evaluating kinetics of elimination of leukemic cells in CSF.

RESULTS

Among 300 patients with newly diagnosed ALL, 87 (29%) had CSF involvement by FCM, while CC was positive in 30 (10%) of 299 patients with available CC data (P < 0.001). Patients with FCM+/CC+ had higher CSF leukemic blast counts compared to patients positive by FCM only (medians: 0.10 vs. 0.017 leukemic blasts/μl, P = 0.006). Patients positive by FCM had higher white blood cell counts in peripheral blood than patients negative by FCM (medians: 45 × 10(9) /l vs. 10 × 10(9) /l, P < 0.001), were younger (medians: 3 years vs. 4 years, P = 0.03), and more frequently had T-cell ALL (18/87 vs. 16/213, P = 0.001). At treatment day 15, five of 52 patients (10%) who had CSF positive by FCM at diagnosis remained so despite at least two doses of weekly intrathecal chemotherapy.

CONCLUSIONS

Longer follow-up is needed to clarify whether FCM positivity has prognostic significance and is an indicator for intensified CNS-directed therapy.

Non-graduation after comprehensive school, and early retirement but not unemployment are prominent in childhood cancer survivors-a Finnish registry-based study

BACKGROUND

In order to assess neurocognitive and social outcomes after childhood cancer, we explored the educational and vocational attainments of Finnish survivors in comparison to matched population controls.

METHODS

From national registries, we identified survivors (n = 3243) born from 1960 to 1992 and aged below 16 at cancer diagnosis (years 1964-2009) as well as their controls (n = 16,215). Data on educational achievements, yearly income, employment status, and retirement were retrieved from Statistics Finland.

RESULTS

The median (range) age at study was 28 (17-50) years. The proportion of those with no education after comprehensive school was higher than controls for all the diagnostic groups: brain tumor (BT) (33.5 vs 23.0 %), solid tumor (ST) (25.0 vs 21.4 %), and leukemia/NHL (29.2 vs 23.1 %). Odds ratios (OR) for unemployment were not significantly elevated in any survivor group compared to controls, but OR for being retired was elevated in each survivor group (BT 14.8, ST 2.2, leukemia/NHL 4.0). Irradiation significantly increased that OR only in BT survivors. Leukemia/NHL survivors treated after 1992 had lower risk for early retirement (OR 0.6) compared to those diagnosed earlier.

CONCLUSIONS

Survivors had higher frequencies than controls for lacking further education after comprehensive school. Unemployment was not common, but risk for early retirement was significantly increased in each three survivor group.

IMPLICATIONS FOR CANCER SURVIVORS

Reassuring is that premature retirement was less common during the most recent treatment era. Screening and follow-up of psychosocial performance more effectively might be essential, and there is a need for studies on possibility for effective rehabilitation of the survivors.