Background: Immunocompromised children with malignancies or after hematopoietic cell transplantation (HCT) often deteriorate before conventional cultures identify a pathogen. Next-generation sequencing (NGS) promises faster, broader detection, yet its clinical impact in pediatric oncology remains unclear. This review aimed to assess the diagnostic performance and clinical utility of NGS in this population. Methods: We searched PubMed, Embase, and Scopus from January 2010 to April 2025 for studies evaluating NGS (metagenomic, targeted, or whole-genome sequencing) in pediatric oncology or HCT patients meeting predefined eligibility criteria. Duplicate screening, data extraction, and Joanna Briggs Institute risk-of-bias appraisal were performed. Heterogeneity precluded formal meta-analysis; findings were synthesized using narrative synthesis complemented by limited quantitative analyses. The protocol was not registered. Results: Twenty-four studies (≥2700 children; 2019–2025) met inclusion criteria. Metagenomic NGS (mNGS) was the most common approach, applied to blood/plasma (46%), bronchoalveolar fluid (BALF) (21%), and other fluids. In culture-negative sepsis or persistent febrile neutropenia, mNGS detected pathogens in 69–86% of episodes versus 18–56% for culture/polymerase chain reaction (PCR). Described in limited studies, early (<48 h) testing shortened fever by ~1.5 days and cut antimicrobial costs by 25–30%. Across studies, treatment was escalated, de-escalated, or discontinued in a median of 63% of mNGS-positive cases. Whole-genome sequencing (WGS) identified 18 silent transmission clusters and resolved a multidrug-resistant Acinetobacter baumannii outbreak within hours. Conclusions: NGS benefits pediatric hemato-oncology by accelerating pathogen-directed therapy, supporting antimicrobial stewardship, and enhancing outbreak surveillance. Despite cost and standardization barriers, evidence supports its use in selected high-risk patients.

Background/Aim: Pediatric patients with primary refractory or relapsed B-cell non-Hodgkin lymphoma (B-NHL) have highly unfavorable prognosis. In this study, we retrospectively analyzed outcomes in pediatric B-NHL patients treated in a single center in Poland from 1995 to 2022, with emphasis on therapy results in patients with progression or relapse. Patients and Methods: The primary objectives were a 5-year probability of overall survival (pOS) and a 5-year probability of event-free survival (pEFS). The secondary objectives involved the assessment of prognostic factors. Results: A total of 76 children were eligible for the analysis. The 5-year pOS was 76.7%, and the 5-year pEFS was 72.9%. At diagnosis, elevated lactate dehydrogenase activity, the presence of B symptoms, bone marrow, skeletal or mediastinal involvement, and stage IV disease were associated with inferior outcomes. Nine children experienced progression and four relapse. The 5-year pOS for patients with progression was 38.1%. Two patients treated with hematopoietic stem cell transplantation (HSCT) as part of salvage therapy survived. However, only one out of seven patients who were treated without HSCT survived. The 5-year pOS was 0.0% in patients with relapsed disease. Conclusion: The most significant factor related to outcomes in pediatric B-NHL is therapy response, with a high mortality rate in children with refractory disease and relapse. There is no consensus on the salvage therapy approach; however, HSCT appears to be the optimal choice.

Background/Aim: Non-B non-Hodgkin lymphomas (NHL) represent over 30 T/NK lymphoma types. The majority of them are T-cell lymphoblastic lymphomas (TLL) and anaplastic large cell lymphomas (ALCL). Other rare non-B NHLs represent a diverse group of neoplasms, usually excluded from clinical trials. This study analyzed outcomes in pediatric patients with non-B NHL in a single oncology center with particular emphasis on patients with rare NHLs. Patients and Methods: We retrospectively analyzed data from patients <18 years with newly diagnosed non-B NHL treated at the Department of Pediatric Hematology and Oncology in Bydgoszcz between 2002 and 2022. The probability of 5-year overall survival (pOS) and event-free survival (pEFS) were calculated for the entire cohort and patients with TLL and ALCL. The clinical course for patients with rare non-B NHL was described in detail. Results: Twenty-six children were eligible for analysis. Fourteen patients were diagnosed with ALCL, nine with TLL, and three with rare NHL types (subcutaneous panniculitis-like T-cell lymphoma, extranodal NK/T-cell lymphoma and hydroa vacciniforme-like lymphoproliferative disease associated lymphoma). For the entire group, the 5-year pOS was 83.7% and the 5-year pEFS was 72.4%. For TLL and ALCL, the outcomes were comparable with those achieved in clinical trials. Patients with rare NHL were treated according to individualized therapy recommendations based on physicians’ expertise and available case report descriptions. Conclusion: There is a lack of knowledge on optimal therapeutic strategies for rare NHLs. It is crucial to create trials dedicated to uncommon NHLs and establish therapy guidelines for these patients.

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Since the beginning of the pandemic, it has been generally accepted that children infected with SARS-CoV-2 either stay asymptomatic or present benign symptoms. Yet SARS-CoV-2 is widely known to cause serious consequences in children and adolescents. Complications may develop during infection, several weeks afterwards, or in the course of multisystem inflammatory syndrome in children (MIS-C). MIS-C manifests with fever, gastrointestinal, cardiovascular and/or neurological symptoms. Moreover, thromboembolism is a relatively common complication of COVID-19 and MIS-C. The purpose of this work was to review current reports on thromboembolic complications among children who underwent SARS-CoV-2 infection. Among the published cases of MIS-C, thromboembolic incidents ranged from 1.4% to 6.5%, taking the form of a brain infarct, deep vein thrombosis, pulmonary embolism, or splenic infarct. Several mechanisms leading to thrombosis in COVID-19 in children are considered. The development of acute infection in the lungs results in local clot formation in the pulmonary microcirculation, leading to perfusion disturbances. ADAMTS13 activity is also mildly reduced in patients infected with SARS-CoV-2, increasing the risk of microthrombosis. COVID-19-associated coagulopathy is characterized by elevated D-dimers and fibrinogen levels. Significantly increased D-dimers probably represent activation of coagulation caused by viremia and cytokine storm, as well as possible organ dysfunction. The treatment of thromboembolism in children includes low and high molecular weight heparins and acetylsalicylic acid. Pediatricians should be aware of the possible multiple complications associated with COVID-19 in children, including thromboembolic incidents. Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Since the beginning of the pandemic, it has been generally accepted that children infected with SARS-CoV-2 either stay asymptomatic or present benign symptoms. Yet SARS-CoV-2 is widely known to cause serious consequences in children and adolescents. Complications may develop during infection, several weeks afterwards, or in the course of multisystem inflammatory syndrome in children (MIS-C). MIS-C manifests with fever, gastrointestinal, cardiovascular and/or neurological symptoms. Moreover, thromboembolism is a relatively common complication of COVID-19 and MIS-C. The purpose of this work was to review current reports on thromboembolic complications among children who underwent SARS-CoV-2 infection. Among the published cases of MIS-C, thromboembolic incidents ranged from 1.4% to 6.5%, taking the form of a brain infarct, deep vein thrombosis, pulmonary embolism, or splenic infarct. Several mechanisms leading to thrombosis in COVID-19 in children are considered. The development of acute infection in the lungs results in local clot formation in the pulmonary microcirculation, leading to perfusion disturbances. ADAMTS13 activity is also mildly reduced in patients infected with SARS-CoV-2, increasing the risk of microthrombosis. COVID-19-associated coagulopathy is characterized by elevated D-dimers and fibrinogen levels. Significantly increased D-dimers probably represent activation of coagulation caused by viremia and cytokine storm, as well as possible organ dysfunction. The treatment of thromboembolism in children includes low and high molecular weight heparins and acetylsalicylic acid. Pediatricians should be aware of the possible multiple complications associated with COVID-19 in children, including thromboembolic incidents.

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Background: The first report on children treated for acute leukemia in Bydgoszcz (Poland) comes from 1958: eleven children were treated with steroids and blood transfusions. Objective: Analysis of results of treatment of children with ALL between 1958–2023 in a single-center study in Poland. Material and methods: A total number of 809 children were included in the study: 215 children treated with various drugs between 1958–1972; 56 children treated with Total Therapy protocols V–VII (St. Jude, Memphis) between 1976–1983; 33 children treated according to BFM-83; 81 children treated according to NOPHO-86 between 1988– –1995; 115 children treated with BFM-90 or New York I/II protocols between 1995–2002; 115 children treated with ALL-IC-2002 between 2002–2011; 95 children treated with ALL-IC-2009 between 2011–2018; and 99 children treated between 2018–2023 with a new international protocol. Results: In respective periods, the following 10-year probabilities of overall survival (pOS) were obtained: p = 0.012 ± 0.008 (1958–1972); p = 0.143 ± 0.047 (1976–1983); p = 0.485 ± 0.087 (1983–1988); p = 0.543 ± 0.055 (1988–1995); p = 0.731 ± 0.042 (1995–2002); p = 0.791 ± 0.038 (2002–2011); p = 0.915 ± 0.021 (2011–2018); and p = 0.962 ± 0.024 (2018–2023) (p <0.0001). After adjustment for the time period, in univariate Cox analysis, in comparison to 2018–2023, the hazard risk (HR) of death was: HR = 2.4 for patients treated between 2011–2018; HR = 5.2 (2002–2011); HR = 6.3 (1995–2002); HR = 12.7 (1988–1995); HR = 13.6 (1983–1988); HR = 38.0 (1976–1983); and HR = 52.4 (1958–1972) (p <0.0001). The hazard risk of leukemic relapse was: HR = 1.9 for patients treated between 2011–2018; HR = 7.6 (2002–2011); HR = 10.4 (1995–2002); HR = 19.9 (1988–1995); HR = 15.9 (1983–1988); HR = 26.0 (1976–1983); and HR = 75.0 (1958–1972) (p <0.0001). The hazard risk of any event was: HR = 1.4 for patients treated between 2011–2018; HR = 4.4 (2002–2011); HR = 4.9 (1995–2002); HR = 8.4 (1988–1995); HR = 8.7 (1983–1988); HR = 18.5 (1976–1983); and HR = 33.4 (1958–1972) (p <0.0001). Conclusions: Complex management of children with ALL based on therapy of international strategy of multidrug chemotherapy and multidirectional supportive therapy has enabled to increase longterm survival from 1% in 1960s to 96% in 2023. Keywords: children acute lymphoblastic leukemia overall survival Gross Domestic Product