Rogachev National Medical Research Center Research Articles

Relapses of congenital mesoblastic nephroma: description of three clinical cases and literature review

Congenital mesoblastic nephroma (CMN) is a rare renal tumor of young children with intermediate biological behavior, accounting for 3.5-4% of all renal tumors in children. СMN is characterized by a favorable prognosis in case of radical surgical treatment. Relapses of CMN are considered to be quite a rare occurrence (4% of all cases), however, both local and metastatic relapses are possible. There are no fully standardized treatment approaches for patients with relapsed CMN. In our study, we performed a retrospective analysis of patients (n = 3) with a verified relapse of CMN who had received treatment at the D. Rogachev NMRCPHOI between 2012 to 2022 (132 months). At relapse, all the patients underwent at least one part of treatment at the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology of Ministry of Healthcare of the Russian Federation. The diagnosis of CMN was established at the Pathology Department of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology of Ministry of Healthcare of the Russian Federation, based on a histological examination. The patients with the cellular histological subtype of CMN underwent fluorescent in situ hybridization testing for ETV6 gene rearrangements. The demographic characteristics, clinical data, the extent of initial treatment and relapse therapy were assessed. Here, we describe three clinical cases of relapse in patients with CMN. The median age at initial diagnosis was 0.8 months (range 0.7–1.4). Our analysis of the extent of primary surgical treatment, including nephrectomy, in all cases revealed the following factors associated with a higher risk of relapse: preoperative tumor rupture – 1, intraoperative tumor rupture – 1, inability to confirm tumor-free margins – 1. The distribution of histological subtypes was as following: classical CMN (n = 1), cellular CMN (n = 1), and mixed CMN (n = 1). One patient had local stage II and 2 patients had local stage III. The median time from diagnosis to disease relapse was 0.8 months (range 2.3–4.3). One patient with mixed CMN died 10.6 months after diagnosis from complications of intensive therapy carried out for extremely aggressive relapse. Two patients are alive after repeated surgical treatment (R1 resection) and adjuvant therapy with actinomycin D and vincristine (AV regimen) for 27 weeks in one case, and neoadjuvant therapy (AV regimen for 4 weeks), delayed surgery (R0 resection), and adjuvant therapy (AV regimen for 4 weeks) in the other case. These patients were followed up for 92.2 and 21.3 months, respectively. By acknowledging the possibility of recurrent CMN, it seems important to provide multidisciplinary clinical care to young children with renal tumors involving a detailed planning of surgical procedures, radical surgeries in accordance with practice guidelines and standards in surgical oncology, and careful follow-up, especially during the first year after surgery. The patients' parents gave consent to the use of their children's data, including photographs, for research purposes and in publications.

Risk factors for functional state deterioration in patients with lymphatic malformation occuring in the neck region

Introduction. The improvement and prediction of functional status in patients with lymphatic malformations of the head and neck, particularly in neck masses, remains a pressing socio-economic concern. As of the publication of this article, no comprehensive scientific studies have explored the cause-and-effect relationships that impact the functional status of this specific patient demographic.Aim. To elucidate the cause-and-effect relationships impacting the functional status of patients with cervical lymphatic malformations and to develop a predictive model for their functional decline.Materials and methods. A retrospective cohort study was conducted, involving a detailed analysis of the functional status of 115 paediatric and adolescent patients aged 1 month to 17 years, treated for cervical lymphatic malformations at the Dmitry Rogachev National Medical Research Center for Pediatric Hematology, Oncology, and Immunology, from May 2012 to December 2022. The analysis utilised the Cologne Disease Score (CDS), varying according to the histological type of the lymphatic malformations (microcystic, macrocystic, or mixed) and the staging of the de Serres classification.Results and discussion. The study involved 115 patients with a median age of 2.1 years (ranging from 0.4 to 5.5 years). It was determined that the ‘Mixed lymphatic malformations type,’ ‘Stage V of the de Serres classification,’ and ‘Need for surgical treatment’ were clinically and statistically significant prognostic factors for the deterioration of functional status in these patients, reducing the CDS scores by 0.976 to 4.514 points, respectively. These findings supported the development of a predictive model for worsening functional status in this group.Conclusion. The predictive model formulated during this research accounts for the histological type, location, and treatment modality, and is recommended for clinical application within specialised medical institutions.

Качество жизни детей и подростков с онкогематологическими заболеваниями в период пандемии COVID‑19

The COVID-19 coronavirus pandemic is affecting the somatic and mental health of populations across the planet. Patients with cancer form a risk group with severe complications of COVID-19. The objective of the study was to examine the quality of life of children and adolescents after completion of antitumor therapy in a pandemic setting. Materials and methods. Specialists from of the clinical and rehabilitation scientific center “Russkoye pole” of the Dmitri Rogachev National Medical Research Center for Pediatric Hematology, Oncology and Immunology conducted a comparative analysis of the results of testing patients and their parents according to the PedsQL™4.0 questionnaires. Results. Patients hospitalized in 2021 have lower physical functioning parameters (63.62) than patients hospitalized before the pandemic in the first half of 2019 (70.89), p < 0.001. Parents reported significantly more positive attitudes towards quality of life assessments during the pandemic compared to those made by children. Conclusion. Differences in quality of life scores between patients in remission of oncohematological diseases before the pandemic and in the pandemic setting based on both children's and parents' assessments have been identified, which may be due to the impact of the novel coronavirus pandemic on some aspects of child and adolescent functioning. Key words: quality of life, oncohematological diseases, COVID-19 coronavirus pandemic, children

Congenital thrombotic thrombocytopenic purpura in children

Introduction. Congenital thrombotic thrombocytopenic purpura (TTP) is a rare and life-threatening genetic disorder characterized by recurrent episodes of microangiopathic hemolytic anemia, thrombocytopenia, and organ dysfunction due to the defi ciency or dysfunction of the ADAMTS13 enzyme. Despite the availability of clinical and laboratory diagnostic criteria the diagnosis remains challenging due to a wide range of diseases with similar appearance.Aim: to analyze the clinical manifestations and treatment results of identifi ed cases of congenital TTP at the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology.Methods. This article reviews 11 clinical cases with congenital TTP genetically confi rmed or with typical clinical and laboratory signs.Results. Clinical and laboratory signs of TTP are highly variable and nonspecifi c, which was observed in the described cohort of patients. One of the trigger factors is often an acute respiratory viral infection, and stabilization of the disease can occur after transfusions of blood components. A delay of diagnosis can often lead not only to a delay of correct therapy, but also to the prescription of wrong therapy. The main diagnosis confi rmatory method was a molecular genetic test, which was carried out in 8 cases. All patients diagnosed with congenital TTP were successfully treated with FFP therapy.Conclusion. Early diagnosis of TTP is diffi cult due to the lack of specifi c clinical manifestations and easily accessible laboratory tests

Secondary malignant tumors in surviving patients with neuroblastoma. The experience of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology

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Bilateral pheochromocytoma in patients with von Hippel–Lindau syndrome: clinical and molecular genetic features

Bilateral adrenal pheochromocytoma (PCС) is extremely rare in children, with major predisposing factors being multiple endocrine neoplasia type 2 and von Hippel–Lindau syndrome. In case of bilateral PCC with underlying von Hippel–Lindau syndrome, organ-preserving surgery is preferred in view of the low malignant potential of such neoplasms. We aimed to study clinical and molecular genetic features of patients with bilateral adrenal PCCs treated at the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology, Ministry of Healthcare of the Russian Federation. The study was approved by the Independent Ethics Committee and the Scientific Council of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology, Ministry of Healthcare of the Russian Federation. The study included 20 patients with paraganglioma (PGL)/PCC (PPGL) who had received treatment (n = 17) or outpatient care (n = 3) at the Center over the period from 2012 to 2023. Bilateral adrenal PCC was diagnosed in 4 (20%) patients. In all these cases, the diagnosis was confirmed by histology. Molecular genetic testing was carried out at the Laboratory of Molecular Biology at the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology, Ministry of Healthcare of the Russian Federation in order to search for germline pathogenic variants in PCC/PGL susceptibility genes. The median age of the four patients with bilateral adrenal PCC was 9.5 years (range 4.5–14.6 years). All the patients were male. In one patient, synchronous bilateral PCC/PGL was observed. In 100% of the cases, arterial hypertension was diagnosed at the onset of the primary disease and was treated with alpha-blockers as part of preparation for surgery. According to the results of a 24-hour urine biochemistry test, all the patients had at least a 4-fold increase above the upper limit of normal for normetanephrine levels. Molecular genetic testing using the multiplex ligation-dependent probe amplification method revealed a pathogenic germline variant in exon 3 of the VHL gene in all the children (4/4). Hereditary PPGL was proven in 2/4 (50%) patients. In all the cases, R0/R1 resection was achieved. Organ-sparing surgery on one/two adrenal glands was performed in 3/4 cases. One out of four (25%) patients developed a local relapse 18.4 months after diagnosis. The overall survival rate in this group was 100%, with a median follow-up time of 8.1 months (range 0.8–50.2 months). Bilateral adrenal PCC is a very rare childhood tumor. A medical genetic consultation is necessary to identify tumor predisposition syndromes. A multidisciplinary team discussion of a surgical strategy is recommended, with organ-sparing surgery on one or two adrenal glands being the treatment of choice that should be carried out at centers specializing in pediatric surgical oncology. Here, we report a rare clinical case of bilateral retroperitoneal PCC/PGL in a patient with von Hippel-Lindau syndrome. The patient's parents gave consent to the use of their child's data, including photographs, for research purposes and in publications.

Angiosarcoma in children: the experience of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology and literature review

Angiosarcoma is a rare and highly malignant endothelial tumor, which occurs mainly in adults and is extremely rare in children and adolescents. The German guidelines for the treatment of soft tissue sarcomas provided by the Cooperative Weichteilsarkom Studiengruppe in 2012 included a separate therapeutic regimen for pediatric angiosarcoma consisting of a combination of vincristine/doxorubicin/cyclophosphamide (VDC) and paclitaxel. The aim of this article was to describe the epidemiological, clinical, and morphological characteristics of angiosarcoma, to review treatment approaches, and to present the experience of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology of Ministry of Healthcare of the Russian Federation in the treatment of children with angiosarcoma. Our study was approved by the Independent Ethics Committee and the Scientific Council of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology of Ministry of Healthcare of the Russian Federation. The study included 5 patients diagnosed with angiosarcoma who had received treatment between 2012 and 2022. The patients’ parents gave consent to the use of their child's data, including photographs, for research purposes and in publications. Data on the patients’ age, gender, tumor location and extension, performed treatment and outcomes of the disease were analyzed. The male:female ratio was 0.66:1 and the median age was 5.2 years. Tumors were located in the soft tissues (n = 3) and in the bones (n = 2). In all the cases, invasion of the surrounding tissues was observed. There were no distant metastases at the time of diagnosis. Two (40%) patients underwent primary resection (R1) and 3 (60%) patients had tumor biopsy. Four patients received therapy according to the German guidelines for the treatment of angiosarcoma (VDC/paclitaxel courses), and 1 patient received treatment according to the guidelines for the management of non-rhabdomyosarcoma soft-tissue sarcomas (courses with vincristine, ifosfamide, doxorubicin/ vincristine, ifosfamide, actinomycin D). Objective response to treatment was achieved in 3 (60%) cases. Local control treatment of these 3 patients consisted of radiation therapy with a total dose of 50.4 Gy after R1 resection in 2 cases and biopsy in 1 case. After a median follow-up of 32 months, 2 patients who had received VDC/paclitaxel were alive without events (with complete and partial response), 3 patients died of progressive disease. Our data confirm the aggressive behavior of angiosarcoma in children. Protocol therapy that includes multiagent chemotherapy based on paclitaxel and doxorubicin along with local control treatment makes it possible to achieve a long-term control of the disease in some patients. However, further research on molecular and genetic characteristics of angiosarcoma is required to find potential novel targets for molecular targeted therapy. Further studies investigating the effectiveness of checkpoint inhibitors in angiosarcoma are also needed.

An analysis of the effectiveness of differential diagnosis and surgical treatment of neck soft-tissue sarcomas in children

We conducted a retrospective sample study with prospective collection of follow-up data. The study was approved by the Independent Ethics Committee and the Scientific Council of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology of Ministry of Healthcare of the Russian Federation. In the time period from January 2013 to August 2020 (92 months), 126 patients with head and neck soft-tissue sarcomas (STS) received treatment at the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology of Ministry of Healthcare of the Russian Federation. We included 25 patients who had undergone surgery for neck STS and divided them into 4 groups (rhabdomyosarcoma (RMS), non-RMS-like STS, RMS-like STS, IRS-IV STS – with distant metastasis at baseline). The median age at the time of correct diagnosis was 2.6 (0.5; 5.0). The median time from symptom onset to the verification of the correct pathomorphological diagnosis was 3.2 (1.6; 4.9) months. We discovered a significant number (13/25, 52%) of cases of biopsy that was performed improperly (excessive/non-diagnostic biopsy, fine-needle aspiration biopsy) at a general inpatient facility. The correct pathomorphological diagnosis was clinically and statistically much more often made at a reference center (20/25, 80%; p = 0.003). Moreover, more than half of pathomorphological diagnoses (8/13, 62%) made at a general inpatient facility were later changed at a reference center. Radical resection was achieved in 17/20 (85%) survivors. In 3/20 (15%) cases, a repeat surgery was not needed because of the patients' complete response to protocol-based treatment. Radiotherapy was carried out in 11/25 (44%) cases. Protocol-based treatment was completed in 19/25 (76%) patients, 18/25 (72%) patients achieved complete response, 2/25 (8%) patients were considered incurable, and 4/25 (16%) children died before the completion of therapy. Post-operative complications of varying severity were observed in 10/25 (40%) cases and were dependent on the degree of STS extension and the severity of the condition of the patients undergoing intensive protocol-based treatment. The median time of patient observation since diagnosis verification was 33.2 (15.6; 74.2) months. The five-year overall survival (OS) was 76.3% (95% confidence interval (CI) 51.8; 89.5), the five-year event-free survival without local disease progression – 73.9% (95% CI 41.8–90.1). Even though there weren't many patients with IRS-IV in our study (4/25, 16%), their exclusion from the analysis resulted in a higher 5-year OS rate: 88.2% (95% CI 60.2; 96.9). This study revealed significant problems in the differential diagnosis of neck STSs in children. In most patients receiving optimal protocol-based treatment, neck tumors can be radically removed at a specialized healthcare facility without mutilating surgery, which results in high 5-year OS and event-free survival rates in patients without distant metastasis. Our findings require further investigation in a larger sample of patients.

Resection of the chest wall for bone and soft tissue neoplasms in children

Chest tumors are quite rare in children. Among them there are benign and malignant. In all cases, surgical intervention is needed; in malignant tumors, as a stage of treatment, it is aimed at removing the tumor and, if necessary, reconstructing the chest wall. Due to the different localization, local spread and involvement of underlying structures, the surgical approach may involve a large extent of chest wall resection, and a variety of plastic materials and techniques is quite wide. During the period from September 2012 to January 2022, 43 surgical interventions for neoplasms of the chest wall in children were performed in the Department of Oncology and Pediatric Surgery of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology. In 11 (26.8%) cases, neoplasms were benign, 30 (73.2%) patients underwent surgical treatment for malignant tumors of various histogenesis. The surgery of the chest wall consisted of two stages. The first stage was a wide excision of the tumor within healthy tissues, performed en bloc with the involvement of underlying tissues and organs (diaphragm). If a malignant process and lung foci were detected, we simultaneously removed the foci on the affected side. The second stage was the reconstruction of the chest wall and diaphragm with local tissues or with the use of non-absorbable synthetic material (polymer meshes, dermal-derived bioprostheses, titanium meshes) shaped according to the size of the defect with a margin for fixation to the edges of the wound. Overall and relapse-free survival was evaluated. The maximum observation period was 9 years. The operative approach and the extent of surgical intervention depend on the size of the primary tumor site and its spread (multifocal lesion), the involvement of adjacent anatomical structures and are individual in each case. The study was approved by the Independent Ethics Committee and the Scientific Council of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology.

Clinical and morphological features of central nervous system tumor with <I>BCOR</I> internal tandem duplication

In 2022, central nervous system (CNS) tumor with BCOR internal tandem duplication (BCOR ITD) was included in the fifth edition of the World Health Organization Classification of Tumors of the CNS as part of the embryonal tumor group. The identification a distinct DNA methylation profile and the presence of a recurrent genetic aberration – BCOR ITD – made it possible to recognize these tumors as a separate entity. In most cases, these tumors occur in children under 5 years of age and are located in the hemispheres of the cerebellum or brain. Since CNS tumor with BCOR ITD is a rare and relatively new tumor entity, it is not yet widely known and can be misdiagnosed. The most common initial diagnosis in patients referred for a second opinion to our reference center is anaplastic/classical medulloblastoma. In this article, we aimed to summarize the characteristic clinical, morphological and immunophenotypic features of CNS tumors with BCOR ITD based on 8 clinical cases confirmed by molecular genetic testing. The study was approved by the Independent Ethics Committee and the Scientific Council of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology.

Clinicogenomic associations in patients with Langerhans cell histiocytosis: a cohort study

This article presents an analysis of genotype and phenotype correlations in a pediatric cohort with Langerhans cell histiocytosis (LCH). Approximately 60% of LCH patients carry BRAF V600E somatic point mutation. Numerous studies have demonstrated that the presence of this mutation is associated with a more severe course of the disease and a higher risk of relapse. Apart from BRAF V600E mutation, other mutations in genes involved in the RAS/RAF/MEK/ERK signaling pathway have been identified in LCH. Next generation sequencing of DNA with high coverage of target regions is considered an optimal approach to detect somatic mutations other than BRAF V600E. The identification of somatic driver mutations holds great potential for enhancing our understanding of the phenotypic heterogeneity of LCH and developing targeted therapeutic strategies. The study was approved by the Independent Ethics Committee and the Scientific Council of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology.

Guidelines for the use of flow cell sorting in diagnosis and monitoring of acute leukemia

Flow cell sorting is an advanced laboratory technique that combines the analytical capabilities of flow cytometry with the ability to isolate pure cell populations from heterogeneous samples. It has tremendous potential both for fundamental research and laboratory diagnosis. For example, the combination of cell sorting and molecular genetic studies can be used to clarify ambiguous results of acute leukemia immunophenotyping obtained both at diagnosis and during minimal residual disease monitoring. These guidelines are based on years of experience in incorporating cell sorting into the diagnostic and monitoring processes at the Leukemia Immunophenotyping Laboratory of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology. They include methods used for the confirmation of flow cytometry data depending on the type of leukemia, the stage of a flow cytometry assay and previous therapy. They also describe cell sorting algorithms for disease diagnosis and the specifics of sample preparation for cell sorting in different molecular genetic studies.

Intracranial mesenchymal tumors with <i>FET–CREB</i> fusion

Intracranial mesenchymal tumors with rearrangements of the genes of the FET and CREB families were first described in the 2021 World Health Organization classification of tumors of the central nervous system. At the moment, the criteria for the diagnosis and treatment of these tumors have not been unambiguously defined. This article presents two exceptionally rare clinical cases of adolescent patients with IMT with the presence of gene rearrangement of the FET and CREB gene families, who were treated and examined at the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology. The patients’ parents gave consent to the use of their children's data, including photographs, for research purposes and in publications.

Flow cytometric and cytomorphological definition of remission achievement in children with B-lineage acute lymphoblastic leukemia

The achievement of remission at the end of induction (EOI) chemotherapy in patients with acute lymphoblastic leukemia (ALL) is the key parameter of treatment effectiveness evaluation. The aim of the study – defining complete remission by multicolor flow cytometry (MFC) and bone marrow (BM) cytomorphology (CM) at the EOI chemotherapy in children with B-lineage ALL. The study was approved by the Independent Ethics Committee and the Scientific Council of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology. The study included patients of “ALL-MB 2008” and “ALL-MB 2015” trials for whom minimal residual disease (MRD) was evaluated by MFC at the EOI simultaneously with CM BM investigation. Less than 5% blasts in BM and MRD < 1% were established as the remission achievement criteria for CM and MFC respectively. The study group included 1498 children aged from 1 to 18 years (median age was 4 years and 11 months) with B-cell precursor ALL. The overall concordance of MFC and CM was found to be 96.1% (1440 of 1498 patients). In 36 (2.4%) children with MRD ≥ 1%, M1 BM status was observed. In contrast, in 22 (1.5%) patients with M2/M3 BM status by CM, MRD value was below 1%. Treatment outcome was analyzed in 522 patients of “ALL-MB 2008” trial. Children with M2/M3 BM, as well as with MRD ≥ 1% demonstrated dramatically inferior outcome, in comparison to those who achieved remission. The presence of at least one of the mentioned criteria (M2/M3 status by CM or MRD ≥ 1% by MFC) defined a group of 23 (4.4%) patients with very low event-free survival (34.9%, standard error 11.0%) and very high cumulative incidence of relapse (56.4%, standard error 12.0%). For the evaluation of remission achievement, MFC and CM should be applied simultaneously at the EOI. High leukemic burden found by any of these methods is the clear definition of induction failure. MRD detection at the EOI should be implemented in any modern treatment protocol as an obligatory stage of treatment response monitoring and final risk group stratification. Considering the crucial importance of the MRD detection results, this study must be performed only in the reference laboratories of the study groups.

A single-center experience of using immunofluorescence staining of blood smears for the diagnosis of hereditary thrombocytopathies

The method of immunofluorescence staining of blood smears is a recently developed approach to the remote diagnosis of various platelet pathologies including MYH9 disorders/MYH9-related disease, biallelic Bernard–Soulier syndrome, Glanzmann thrombasthenia, gray platelet syndrome, and others. We report here the experience of introducing this method at the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology (Moscow, Russia), which is the main national pediatric hematology hospital that provides diagnosis and therapy to children with blood disorders throughout the country. Our study aimed to transfer this relatively labor-intensive and skill-sensitive method and introduce it into routine laboratory practice, and to perform its validation. The study was approved by the Independent Ethics Committee and the Scientific Council of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology.

Using immature platelet fraction as a factor in deciding on the need for platelet transfusions

Our study aimed to assess the prognostic significance of immature platelet fraction (IPF) and its role in deciding whether to transfuse platelets. The study was approved by the Independent Ethics Committee and the Scientific Council of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology. We monitored this hematologic parameter in 6 patients before and after hematopoietic stem cell transplantation (HSCT). For the study, we used whole blood collected in K EDTA tubes. IPF levels were measured by flow cytometry on the automated hematology analyzer SYSMEX XE-2100 (Sysmex, Kobe, Japan). The presence of platelet antibodies was detected using Capture-P Ready-Screen solid phase system for the detection of antibodies to platelets and the NEO Blood Bank Analyzer by Immucor, Inc. It was shown that the use of IPF enabled an early establishment of platelet engraftment and helped to make more a reasoned decision regarding the transfusion of platelets. It was established that if a rise in IPF > 6% was not accompanied by an increase in platelet count, serum platelet antibody testing was needed. IPF can help diagnose platelet engraftment failure following HSCT and thus eliminate the need for bone marrow aspiration. IPF is of great clinical importance; if adopted as a routine hematologic parameter, it can serve as an additional factor in deciding on the need for platelet transfusions and platelet antibody testing and subsequent personalized selection of platelets.

The efficacy of the TRK inhibitor entrectinib in patients with extracranial <i>NTRK</i> fusion-positive tumors

Somatic translocations involving the NTRK genes occur in 0.34–2.2% of all malignant neoplasms in children. TRK inhibitors whose efficacy has been demonstrated in prospective clinical studies expand treatment options for patients with solid tumors harboring NTRK gene rearrangements. The aim of our study was to summarize the first Russian experience with the use of the TRK inhibitor entrectinib in patients with extracranial NTRK fusion-positive solid tumors included in the compassionate use program. This study was approved by the Independent Ethics Committee and the Academic Council of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology. The study included 8 patients who had been treated at the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology and the N.N. Blokhin National Medical Research Center of Oncology. The main criteria for inclusion in the compassionate use program were a confirmed rearrangement of either NTRK1/2/3 genes in a solid tumor in patients with unresectable disease for whom no effective standard systemic therapy was available, progressive or recurrent disease during therapy prescribed according to the established diagnosis, risk group and risk stratification criteria, and the infeasibility of non-mutilating radical surgery. The median age at diagnosis was 4.3 months (range 1.2–83.6). The male to female ratio was 1:1. The primary site distribution was as follows: head and neck (n = 6; 75%), chest wall (n = 1; 12.5%), pelvis (n = 1; 12.5%). None of the patients had regional lymph node involvement or distant metastases at diagnosis. The distribution by histology (according to histopathology reports) was as follows: infantile fibrosarcoma (n = 4; 50%), undifferentiated round cell sarcoma, low-grade (n = 1; 12.5%), undifferentiated spindle cell sarcoma, high-grade (n = 1; 12.5%), NTRK-rearranged spindle cell sarcoma, low-grade (n = 1; 12.5%), spindle cell tumor associated with an NTRK rearrangement (n = 1; 12.5%). Immunohistochemistry (IHC) with a pan-Trk monoclonal antibody was performed in 7/8 (87.5%) patients. Pan-Trk IHC was positive in 4/7 (57%) patients. Rearrangements in the NTRK1 and NTRK3 genes were confirmed in all the patients. The final methods used for the detection of fusion transcripts were as follows: reverse transcription polymerase chain reaction (n = 4; 50%) and RNA-based next-generation sequencing (n = 4; 50%). NTRK1 and NTRK3 gene translocations were detected in 3/8 (37.5%) and 5/8 (62.5%) patients, respectively. The following fusion transcripts were identified: ETV6::NTRK3 (n = 4), DIP2C::NTRK3 (n = 1), TPR::NTRK1 (n = 1), TPM3::NTRK1 (n = 1), MYH10::NTRK1 (n = 1). One (12.5%) patient received entrectinib as first-line therapy, other patients (7/8, 87.5%) received entrectinib as secondor subsequent-line therapy. Three (37.5%) patients had undergone surgery before treatment with entrectinib: 2 had R2 resection, 1 had R0/R1 resection (resection margins were not evaluated). None of the patients received radiation therapy. The median duration of entrectinib therapy at the time of analysis was 11.8 months (range 2.3–20.1). Delayed surgery was performed in 2/8 patients; according to the histopathology reports, they achieved grade IV pathomorphosis. Three patients experienced adverse events during treatment with entrectinib. The median time to adverse events was 0.23 months (range 0.2–7.96). Three patients required temporary interruption in treatment to relieve symptoms, a subsequent dose reduction by one dose level was necessary when resuming therapy in two patients. The median follow-up since diagnosis was 19.5 months (range 14.9–75.0). All the patients included in our analysis were alive, three of them had no radiologic evidence of disease. Fifty percent of the patients completed targeted therapy, another 50% of the patients continued treatment with entrectinib. Complete and very good partial response was achieved in 3/8 and 2/8 patients, respectively. Partial response, minor partial response and stable disease were observed in one patient each. These results indicate high efficacy and safety of entrectinib in pediatric patients with extracranial NTRK fusion-positive solid tumors. Further studies are needed to determine the therapeutic potential of TRK inhibitors in the treatment of different solid malignant neoplasms in children and to assess long-term treatment results.

The results of therapy with venetoclax, daratumumab and plerixafor as part of the conditioning regimen in chemotherapy-refractory acute leukemia in children

The main outcomes of allogeneic hematopoietic stem cell transplantation (HSCT) in chemotherapy-refractory acute leukemia remain suboptimal due to a high relapse rate. The incorporation of targeted anti-leukemia agents into the conditioning regimens is a potential approach to improve the efficacy of HSCT. We assessed the safety and potential efficacy of the addition of venetoclax, daratumumab, and plerixafor to the conditioning regimens in children with chemotherapy-refractory acute leukemias who received allogeneic TCRab/CD19-depleted HSCT. We used data from a pilot study, as well as the data of patients from a retrospective cohort who received similar therapy according to the individual indications. The study was approved by the Independent Ethics Committee and the Scientific Council of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology. All 43 patients (33 acute myeloid leukemias (AML), 8 T-cell acute lymphoblastic leukemias (T-ALL) and 2 acute leukemias of ambiguous lineage) had active disease status at the time of transplantation. The preparative regimen included myeloablative conditioning based on either total body irradiation or treosulfan or melphalan. A haploidentical related donor was used as a graft source in 38 cases, while a fully matched related or unrelated donor was used in 5 cases. The engraftment was observed in 93% of cases, no excessive toxicity was noted. MRD-negative complete remission was achieved in 37 patients (86%). The cumulative incidence of grade II–IV acute graft-versus-host disease (GvHD) was 10%, and the cumulative incidence of chronic GvHD was 5%. At 2 years, transplant-related mortality was 7%, relapse incidence was 52%, event-free survival was 41%, and overall survival was 51%. The overall survival rate for the AML group was 58% and 25% for the T-ALL group. Our data show that the addition of targeted agents to the conditioning regimens is safe, however, does not significantly improve the results of HSCT in the study cohort of patients.

Quantitative bone marrow magnetic resonance imaging in children with lymphoblastic leukaemia

The aim of the study was to evaluate fat fraction (FF) changes in patients diagnosed with acute lymphoblastic leukaemia (ALL) in comparison with children without haematological disorders. All the patients or their legal representatives gave their informed consent to magnetic resonance imaging (MRI). The study was approved by the Independent Ethics Committee and the Scientific Council of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology and was conducted in line with the Ethical Principles of the World Health Organization (the Declaration of Helsinki) for Medical Research Involving Human Subjects. The study included 33 healthy volunteers aged 13.4 ± 2.8 years (the control group) and 34 patients with acute phase ALL whose mean age was 12.2 ± 3.6 years (the group of interest). Imaging of the pelvic bones and lumbar vertebrae was performed on a Philips Achieva 3T scanner using the mDixon-quant sequence, with a subsequent construction of FF maps. The Mann–Whitney U-test was used to compare the FF data of the cases with each other and with the controls. Four regions of interest were selected, 100 mm2 each: in the bodies of the right and the left iliac bones as well as in the bodies of the L4 and L5 vertebras. For each group of subjects and each region of interest, mean FF was calculated. In the group of the patients with acute phase ALL, FF was the lowest: 3.53 ± 2.75% and 3,72 ± 3.09% in the bodies of the left and right iliac bones respectively, and 2.62 ± 1.86% and 2.47 ± 2.17% in the L4 and L5 vertebras respectively. In the control group, FF in the respective regions of interest was 51.3 ± 9.5%; 49.9 ± 11.0%; 31.3 ± 8.73% and 32.4 ± 10.3%. It is obvious that bone marrow FF in the patients with ALL differs significantly from the control group. Quantitative MRI can become a new method for the assessment of changes in the bone marrow of children with leukaemias.

БОЛЬШИЕ ДАННЫЕ И ВИЗУАЛЬНАЯ АНАЛИТИКА В ДЕТСКОЙ ОНКОЛОГИИ И ГЕМАТОЛОГИИ

The potential of big data in healthcare relies on the ability to detect patterns and turn high volumes of data into actionable knowledge for precision medicine and decision makers. Due to constantly increasing amount of data, healthcare systems around the world are facing challenges associated with data processing and analysis while keeping costs under control. There is a number of examples where the use of big data in healthcare already provides solutions that optimize patient care and generate value for healthcare institutions. However, a further increase in the amount and variety of dynamically changing data in healthcare systems requires that all the relevant stakeholders collaborate and adapt the design and performance of their systems. To this end, it is necessary both to invest in the human capital and to build the technological infrastructure to house and converge a huge volume of healthcare data. It is also important to provide a set of tools that can improve data analytics by creating interactive visual interfaces to help analysts navigate and make sense of massive datasets. Here we provide an overview of international advanced initiatives related to big data analytics in various sectors of public healthcare that are aimed at obtaining new knowledge, improving clinical care and rationalizing epidemiological surveillance. Here we also share our own experience of applying visual analytics tools in the "Electronic Passport of Pediatric Oncology and Hematology Service." This passport was created by specialists from the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology of Ministry of Healthcare of Russia in order to improve the quality of specialized care in the Russian regions. This software solution is based on data from checklists and questionnaires (baseline assessment) completed during an outreach event and its preparation as well as from correspondence regarding the implemented corrective measures (baseline and follow-up assessments). This system is an important tool that helps improve the quality of monitoring of the pediatric oncology and hematology service. The structured electronic database allows the user to rank the Russian regions based on a whole range of parameters as well as to generate recommendations for process optimization in regional institutions. In such a complex information system, a user-friendly interface for the processing of large volumes of heterogeneous dynamic data is crucially important.