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The epidemiology of infant acute lymphoblastic leukemia (ALL), hypodiploid ALL, and mixed-phenotype acute leukemia (MPAL) in Canada is unknown. The main objective was to describe the prevalence, prognostic factors, and outcomes of three rare and high-risk ALL subtypes in Canada. This is a retrospective study using the Cancer in Young People-Canada (CYP-C) database. Event-free survival (EFS) and overall survival (OS) were described by the Kaplan–Meier method and compared using the log-rank test. Among 2626 children aged 0–14 years diagnosed with B-cell acute lymphoblastic leukemia (B-ALL) between 2001 and 2018, 227 (8.6%) patients were identified to be infant ALL (n = 139), hypodiploid ALL (n = 43), or MPAL (n = 45). The 5-year EFS/OS was significantly worse in the infant ALL subgroup compared to that of hypodiploid ALL and MPAL. For the entire cohort, presenting White blood cells (WBCs) ≥50 × 109/L was independently associated with worse EFS/OS. [ABSTRACT FROM AUTHOR]

Background: Alloimmunisation and haemolytic transfusion reactions (HTRs) can occur in patients with sickle cell disease (SCD) despite providing phenotype‐matched red blood cell (RBC) transfusions. Variant RBC antigen gene alleles/polymorphisms can lead to discrepancies in serological phenotyping. We evaluated differences between RBC antigen genotyping and phenotyping methods and retrospectively assessed if partial antigen expression may lead to increased risk of alloimmunisation and HTRs in SCD patients at a tertiary centre in Canada. Methods: RBC antigen phenotyping and genotyping were performed by a reference laboratory on consenting SCD patients. Patient demographic, clinical and transfusion‐related data were obtained from a local transfusion registry and chart review after research ethics board approval. Results: A total of 106 SCD patients were enrolled, and 91% (n = 96) showed additional clinically relevant genotyping information when compared to serological phenotyping alone. FY*02N.01 (FY*B GATA‐1) (n = 95; 90%) and RH variant alleles (n = 52, 49%; majority accompanied by FY*02N.01) were common, the latter with putative partial antigen expression in 25 patients. Variability in genotype‐phenotype antigen prediction occurred mostly in the Rh system, notably with the e antigen (kappa: 0.17). Fifteen (14.2%) patients had a history of alloimmunisation, with five having HTR documented; no differences in clinical outcomes were found in patients with partial antigen expression. Genotype/extended‐phenotype matching strategies may have prevented alloimmunisation events. Conclusion: We show a high frequency of variant alleles/polymorphisms in the SCD population, where genotyping may complement serological phenotyping. Genotyping SCD patients before transfusion may prevent alloimmunisation and HTRs, and knowledge of the FY*02N.01 variant allele increases feasibility of finding compatible blood. [ABSTRACT FROM AUTHOR]

Background: l-asparaginase is a universal component of treatment for childhood acute lymphoblastic leukaemia, and is usually administered intramuscularly. Pegylated Escherichia coli asparaginase (PEG-asparaginase) has a longer half-life and is potentially less immunogenic than the native Escherichia coli (E coli) preparation, and can be more feasibly administered intravenously. The aim of the Dana-Farber Cancer Institute Acute Lymphoblastic Leukaemia Consortium Protocol 05-001 (DFCI 05-001) was to compare the relative toxicity and efficacy of intravenous PEG-asparaginase and intramuscular native E colil-asparaginase in children with newly diagnosed acute lymphoblastic leukaemia.Methods: DFCI 05-001 enrolled patients aged 1-18 years with newly diagnosed acute lymphoblastic leukaemia from 11 consortium sites in the USA and Canada. Patients were assigned to an initial risk group on the basis of their baseline characteristics and then underwent 32 days of induction therapy. Those who achieved complete remission after induction therapy were assigned to a final risk group and were eligible to participate in a randomised comparison of intravenous PEG-asparaginase (15 doses of 2500 IU/m(2) every 2 weeks) or intramuscular native E colil-asparaginase (30 doses of 25 000 IU/m(2) weekly), beginning at week 7 after study entry. Randomisation (1:1) was unmasked, and was done by a statistician-generated allocation sequence using a permuted blocks algorithm (block size of 4), stratified by final risk group. The primary endpoint of the randomised comparison was the overall frequency of asparaginase-related toxicities (defined as allergy, pancreatitis, and thrombotic or bleeding complications). Predefined secondary endpoints were disease-free survival, serum asparaginase activity, and quality of life during therapy as assessed by PedsQL surveys. All analyses were done by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00400946.Findings: Between April 22, 2005, and Feb 12, 2010, 551 eligible patients were enrolled. 526 patients achieved complete remission after induction, of whom 463 were randomly assigned to receive intramuscular native E colil-asparaginase (n=231) or intravenous PEG-asparaginase (n=232). The two treatment groups did not differ significantly in the overall frequency of asparaginase-related toxicities (65 [28%] of 232 patients in the intravenous PEG-asparaginase group vs 59 [26%] of 231 patients in the intramuscular native E colil-asparaginase group, p=0·60), or in the individual frequency of allergy (p=0·36), pancreatitis (p=0·55), or thrombotic or bleeding complications (p=0·26). Median follow-up was 6·0 years (IQR 5·0-7·1). 5-year disease-free survival was 90% (95% CI 86-94) for patients assigned to intravenous PEG-asparaginase and 89% (85-93) for those assigned to intramuscular native E colil-asparaginase (p=0·58). The median nadir serum asparaginase activity was significantly higher in patients who received intravenous PEG-asparaginase than in those who received intramuscular native E colil-asparaginase. Significantly more anxiety was reported by both patients and parent-proxy in the intramuscular native E colil-asparaginase group than in the intravenous PEG-asparaginase group. Scores for other domains were similar between the groups. The most common grade 3 or worse adverse events were bacterial or fungal infections (47 [20%] of 232 in the intravenous PEG-asparaginase group vs 51 [22%] of 231 patients in the intramuscular E colil-asparaginase group) and asparaginase-related allergic reactions (14 [6%] vs 6 [3%]).Interpretation: Intravenous PEG-asparaginase was not more toxic than, was similarly efficacious to, and was associated with decreased anxiety compared with intramuscular native E colil-asparaginase, supporting its use as the front-line asparaginase preparation in children with newly diagnosed acute lymphoblastic leukaemia.Funding: National Cancer Institute and Enzon Pharmaceuticals. [ABSTRACT FROM AUTHOR]

There are conflicting data about whether the development of cancer-associated thrombo-embolism (TE) negatively impacts survival in children. The objective was to determine whether TE during treatment was associated with overall survival (OS) and event-free survival (EFS) in children with acute lymphoblastic leukemia (ALL). We performed a population-based retrospective cohort study using the Cancer in Young People-Canada registry. Children <15 years of age were diagnosed with de novo ALL (2000-2016). The primary exposure variable was radiologically-confirmed thrombo-embolism requiring medical intervention. Multivariable Cox regression models were used to determine the impact of thrombo-embolism on survival, where TE was time-dependent. We included 2006 children (median age: 4 years, 88.5% precursor B-cell ALL). Thrombo-embolism occurred in 113 patients (5.6%), at a median time of 107 days (interquartile range: 35-184 days) after ALL diagnosis. Among standard/low-risk patients, 41/1165 (3.5%) developed TE while among high/very high-risk patients, 72/841 (8.6%) developed TE. Patients with TE had a significantly worse OS (adjusted HR [aHR] of death: 2.61, 95% CI: 1.62-4.22, p < 0.001) and EFS (aHR of an event [death, relapse, second malignancy]: 2.03, 95% CI: 1.35-3.05, p = 0.001), compared with patients without TE. No statistically significant difference was seen in standard/low risk ALL for OS and EFS, but TE was associated with a significantly lower OS and EFS in children with high/very high-risk ALL (aHR of death: 2.90, 95% CI: 1.79-4.72, p < 0.001; aHR of an event: 2.02, 95% CI: 1.30-3.12, p = 0.002). Thus, TE led to a statistically significant reduction in OS and EFS in children with high risk/very high-risk leukemia., (© 2021 Wiley Periodicals LLC.)

There is conflicting information about the epidemiology of thromboembolism (TE) in paediatric oncology. Objectives were to describe the incidence and risk factors of TE in children with cancer. We included all children with cancer less than 15 years of age diagnosed from 2001 to 2016, treated at one of the 12 Canadian paediatric centres outside of Ontario and entered into the Cancer in Young People-Canada database. Potential risk factors for TE were evaluated using Cox proportional hazards regression stratified by haematological malignancies versus solid tumours. Factors associated with vascular access- and non-vascular access-related TE were compared using chi-square or Fisher's exact tests. Of the 7,471 children included, 283 experienced TE requiring medical intervention; cumulative incidence of TE at 5 years was 3.8 ± 0.2% and 0.36% ± 0.07% for life-threatening or fatal TE. For haematological malignancies, the following factors were associated with TE in multivariable regression: age < 1 year, 5 to 9.99 years and 10 to 14.99 years (relative to age 1-4.99 years), haematopoietic stem cell transplant (hazard ratio [HR] = 1.49, 95% confidence interval [CI], 1.00-2.32), anthracyclines (HR = 2.21, 95% CI, 1.12-4.37) and asparaginase (HR = 1.68, 95% CI, 1.15-2.44). For solid tumours, obesity (HR = 1.92, 95% CI, 1.01-3.68), surgery (HR = 2.70, 95% CI, 1.44-5.08), radiation (HR = 47.51, 95% CI, 24.01-94.01), anthracyclines (HR = 2.74, 95% CI, 1.29-5.82) and platinum agents (HR = 2.26, 95% CI, 1.19-4.28) were associated with TE. Life-threatening and fatal TEs were more common among non-vascular access TEs (14.5% vs. 3.3% p  = 0.001). In a population-based cohort, 4% of children with cancer developed a clinically significant TE. Accurate risk stratification tools are needed specific to malignancy type., Competing Interests: None of the authors have competing interest to disclose. Dr. Marie-Claude Pelland-Marcotte's fellowship at the Hospital for Sick Children (Toronto, Canada) was supported by Shire Endowment Fund for Training in Pediatric Hemostasis., (Georg Thieme Verlag KG Stuttgart · New York.)

We evaluated the effects of body mass index (BMI) on the risk of thromboembolism (TE) in children (<18 years) with hematological malignancies during the period 1990-2009 (n = 359). Obesity was prevalent in 12% of patients: 6% versus 17% prior to and after the year 2000 (P = 0.02). Sixty-one (17%) patients developed TE; increasing BMI was associated with increased, but statistically insignificant risk of TE [adjusted odds ratios (OR): 0.75 (95%CI 0.32-1.77), 0.93 (95%CI 0.38-2.30), and 1.01(95%CI 0.42-2.41) for underweight, overweight, and obese group]. A large prospective study is needed to define the impact of BMI on the risk of TE in children., (Copyright © 2011 Wiley Periodicals, Inc.)

Objective: Unclassified inherited bone marrow failure syndromes are a heterogeneous group of genetic disorders that represent either new syndromes or atypical clinical courses of known inherited bone marrow failure syndromes. The relative prevalence of the unclassified inherited bone marrow failure syndromes and their characteristics and the clinical and economic challenges that they create have never been studied., Methods: We analyzed cases of inherited bone marrow failure syndrome in the Canadian Inherited Marrow Failure Registry that were deemed unclassifiable at study entry., Results: From October 2001 to March 2006, 39 of the 162 patients enrolled in the Canadian Inherited Marrow Failure Registry were registered as having unclassified inherited bone marrow failure syndromes. These patients presented at a significantly older age (median: 9 months) than the patients with classified inherited bone marrow failure syndrome (median: 1 month) and had substantial variation in the clinical presentations. The hematologic phenotype, however, was similar to the classified inherited bone marrow failure syndromes and included single- or multiple-lineage cytopenia, severe aplastic anemia, myelodysplasia, and malignancy. Grouping patients according to the affected blood cell lineage(s) and to the presence of associated physical malformations was not always sufficient to characterize a condition, because affected members from several families fit into different phenotypic groups. Compared with the classified inherited bone marrow failure syndromes, the patients with unclassified inherited bone marrow failure syndromes had 3.2 more specific diagnostic tests at 4.5 times higher cost per evaluated patient to attempt to categorize their syndrome. At last follow-up, only 20% of the unclassified inherited bone marrow failure syndromes were ultimately diagnosed with a specific syndrome on the basis of the development of new clinical findings or positive genetic tests., Conclusions: Unclassified inherited bone marrow failure syndromes are relatively common among the inherited bone marrow failure syndromes and present a major diagnostic and therapeutic dilemma.