C hildren and adolescents with pre-existing conditions such as DNA repair defects or other primary immunodeficiencies have an increased risk of non-Hodgkin lymphoma. However, largescale data on patients with non-Hodgkin lymphoma and their entire spectrum of pre-existing conditions are scarce. A retrospective multinational study was conducted by means of questionnaires sent out to the national study groups or centers, by the two largest consortia in childhood non-Hodgkin lymphoma, the European Intergroup for Childhood non-Hodgkin Lymphoma, and the international BerlinFrankfurt-Münster Study Group. The study identified 213 patients with non-Hodgkin lymphoma and a pre-existing condition. Four subcategories were established: a) cancer predisposition syndromes (n=124, 58%); b) primary immunodeficiencies not further specified (n=27, 13%); c) genetic diseases with no increased cancer risk (n=40, 19%); and d) non-classifiable conditions (n=22, 10%). Seventy-nine of 124 (64%) cancer predispositions were reported in groups with more than 20 patients: ataxia telangiectasia (n=32), Nijmegen breakage syndrome (n=26), constitutional mis-

Data on management of pediatric marginal zone lymphoma (MZL) are scarce. This retrospective study assessed characteristics and outcome in 66 patients who were <18 years old. Forty-four (67%) had an extranodal MZL (EMZL), 21 (32%) a nodal MZL (NMZL), and one patient a splenic MZL. Thirty-three patients (50%) received a variable combination of adjuvant chemotherapy/immunotherapy/radiotherapy, while the remainder, including 20 of 21 with NMZL, entered an active observation period. Overall survival was excellent (98 ± 2%), although 11 patients relapsed (17%; NMZL, n = 1; EMZL, n = 10), seven after any therapy and four after complete resection only. In conclusion, outcome of NZML, in particular, seems to be excellent after (in)complete resection and observation only.

Tremendous progress in the therapy of pediatric acute lymphoblastic leukemia (ALL) has been achieved through combination cytotoxic chemotherapy, leading to high cure rates, at the cost of significant life-threatening toxicity. The bispecific T-cell engager blinatumomab, recently approved for relapsed/refractory ALL, has a unique nonmyelotoxic toxicity profile. As blinatumomab causes B-cell depletion, the safety of its use during severe chemotherapy-induced toxicity is unclear. We report 11 pediatric patients with ALL, treated with blinatumomab following overwhelming chemotherapy-associated toxicity, with recovery of all patients and successful bridging to further antileukemia therapy. Blinatumomab can be considered for rare patients who cannot tolerate cytotoxic therapy. K E Y W O R D S blinatumomab, childhood acute lymphoblastic leukemia, immunotherapy, treatment-related toxicity Abbreviations: ALL, acute lymphoblastic leukemia; B-ALL, B-cell precursor acute lymphoblastic leukemia; DS, Down syndrome; MRD, minimal residual disease; R/R, relapsed/refractory.

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Background COVID-19, the novel coronavirus has caused a global pandemic affecting millions of people around the world. Although children, including children with cancer, have been found to be affected less commonly and less severely than adults, indirect effects of the pandemic on the diagnosis and treatment of children with cancer have been less described. Methods A survey was performed in the four largest tertiary pediatric hematology-oncology medical centers in Israel. Clinical and laboratory data were collected from the medical files of patients diagnosed or treated with cancer during April–October 2020. Results Seventeen patients are described, who had a significant delay in diagnosis or treatment of cancer. These represent approximately 10% of all pediatric cancer diagnosed during the study period in these centers. A main cause of delay was fear of exposure to COVID-19 (fears felt by the patient, parent, physician, or decision-makers at the institution; or the implementation of national guidelines). Delays also resulted from co-infection with COVID-19 and the attribution of the oncologic symptoms to the infection. In addition, treatment was delayed of patients already diagnosed with cancer, due to COVID-19 infection detected in the patient, a family member, or a bone marrow donor. Conclusion Fear from the COVID-19 pandemic may result in delayed diagnosis and treatment of children with cancer, which may carry a risk to dismal prognosis. It is crucial that pediatricians and patients alike remember that other diseases still prevail and must be thought of and treated in a timely fashion.

Summary This study investigated the prevalence of inherited thrombophilia, risk of venous thromboembolism (VTE) and benefit of low molecular weight heparin prophylaxis in 476 Israeli children with acute lymphoblastic leukaemia (ALL) treated between 2004 and 2016. Thrombophilia was found in 15·5%. Arab children had a higher prevalence of F5 R506Q (factor V Leiden) than Jewish children (19·4% vs. 2·9%, P < 0·01). Patients with thrombophilia had higher VTE rates VTE (26·5% vs. 5·6%, P < 0·001). None of the thrombophilic children given prophylaxis had severe VTE. Routine evaluation for inherited thrombophilia followed by thromboprophylaxis when findings are positive may benefit at‐risk patients with ALL.

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Mucormycosis has emerged as an increasingly important cause of morbidity and mortality in immunocompromised patients, but contemporary data in children are lacking. We conducted a nationwide multicentre study to investigate the characteristics of mucormycosis in children with haematological malignancies. The cohort included 39 children with mucormycosis: 25 of 1136 children (incidence 2Á2%) with acute leukaemias prospectively enrolled in a centralized clinical registry in 2004-2017, and an additional 14 children with haematological malignancies identified by retrospective search of the databases of seven paediatric haematology centres. Ninety-two percent of mucormycosis cases occurred in patients with acute leukaemias. Mucormycosis was significantly associated with high-risk acute lymphoblastic leukaemia (OR 3Á75; 95% CI 1Á51-9Á37; P = 0Á004) and with increasing age (OR 3Á58; 95% CI 1Á24-9Á77; P = 0Á01). Fifteen patients (38%) died of mucormycosis. Rhinocerebral pattern was independently associated with improved 12-week survival (OR 9Á43; 95% CI 1Á47-60Á66; P = 0Á02) and relapsed underlying malignancy was associated with increased 12-week mortality (OR 6Á42; 95% CI, 1Á01-40Á94; P = 0Á05). In patients receiving frontline therapy for their malignancy (n = 24), one-year cumulative mucormycosis-related mortality was 21 AE 8% and five-year overall survival was 70 AE 8%. This largest paediatric population-based study of mucormycosis demonstrates that children receiving frontline therapy for their haematological malignancy are often salvageable. ALL, acute lymphoblastic leukaemia; AML, acute myeloid leukaemia; SCT, stem cell transplantation. *Variables are presented as n (%), unless otherwise stated. † The dash indicates that the variable was entered into the initial multivariate logistic regression model based on its P value in the univariate analysis (≤0Á10), but it was removed from the final model through the backward elimination procedure. ‡ Lymphocytopenia and monocytopenia were not included in the multivariate analysis as only a subcategory of patients had evaluable data. Surgical interventions were not included in order to avoid possible selection bias. SCT was not included due to its high correlation with relapsed and refractory disease (phi coefficient = 0Á78 and 0Á65, respectively).