Neuroblastoma is the most common extracranial solid tumor in children 0–14 years old. Current risk-adapted treatment programs are based on stratification of patient into three risk groups. 40–50% of patients are stratified into the high-risk group. The prognosis in high-risk patients remains poor (the probability of long-term survival is less than 50%), despite the use of aggressive multimodal therapy, including high-dose chemotherapy and autologous hematopoietic stem cell transplantation. In most cases tumor cells in neuroblastoma express disialoganglioside GD2, which is a possible target for immunotherapy. Over the past 30 years, GD2-directed chimeric monoclonal antibodies ch14.18 have been introduced into clinical practice. A number of clinical studies have shown an improvement in the prognosis in patients with high-risk neuroblastoma, when using monoclonal antibodies ch14.18, primarily due to the eradication of the minimal residual population of tumor cells resistant to standard chemotherapy. This literature review summarizes the international experience in the use of monoclonal antibodies ch14.18 from early phases of clinical trials to large randomized trials, which allowed immunotherapy to be considered as an important component of multimodal therapy for high-risk neuroblastoma. Future prospects for the use and place of immunotherapy in first-line therapy of high-risk neuroblastoma and in relapsed setting are considered.

Clear cell sarcoma of the kidney (CCSK) is a rare malignant renal tumor in children, which accounts for 2–5% of pediatric kidney malignancies. The aim of the study was to analyze the results of therapy of patients with CCSK treated in Dmitry Rogachev National Medical Research Center оf Pediatric Hematology, Oncology and Immunology. Retrospective analysis of patients with a histologically confirmed diagnosis of CCSK treated for the period 01.2012–02.2020 (98 months) was done. The study was approved by the Independent Ethics Committee and the Scientific Council of the D. Rogachev NMRCPHOI of the Ministry of Healthcare of the Russian Federation. Demographic characteristics, clinical symptoms, methods of diagnosis, and treatment modalities were analyzed. Patients were treated according to the protocols of the SIOP-RTSG group (SIOP 93-01, SIOP-2001, SIOP-RTSG-2016). The stage was assigned according to the SIOP classification. Overall and event-free survival was assessed by the Kaplan–Mayer method. The analysis of the results was carried out on 01.03.2021. The analysis included 10 patients with CCSK. The median age at the time of diagnosis of CCSK was 30.1 months (range 13.5–70.8 months). All patients were male. The duration from the onset of the first symptoms/detection of the tumor to the diagnosis was 0.8 months (range 0.1–3.2 months). The diagnosis was established on the basis of clinical and radiological data (n = 9) and biopsy (n = 1). Distant metastases at the time of diagnosis were detected in 1 (10%) patient (localization of metastases - lungs). The median tumor volume was 439 cm3 (range 256–996 cm3 ). Preoperative chemotherapy was performed in all patients (AV regimen (actinomycin D, doxorubicin) in 7 (70%) patients). Assessment of response after preoperative chemotherapy showed tumor regression in 3/10 (in 1/7 with AV regimen), tumor progression in 5 and stable disease in 2 patients. Surgical treatment in the extent of nephrectomy was performed in all patients. In 1 (10%) case, intraoperative tumor rupture was documented. Distribution of patients by local stages: I – 4/10 (40%), II – 2/10 (20%), III – 4/10 (40%) (including 1 patient with distant metastases). In 1 patient, a left thoracotomy was performed to exclude lung metastases. Adjuvant chemotherapy was performed in all patients in accordance with the relevant protocols of the high-risk group: 7 – 4–5-drug regimen, 3 – AVD regimen (actinomycin D, vincristine, doxorubicin). Radiation therapy was performed in 6/10 (60%) patients. Outcomes: 9/10 (90%) – alive, 1/10 (10%) patient died (non-tumor-related death). 3-year event-free survival and overall survival were 78.8% (95% confidence interval (CI) 52.5–100) and 90.0% (95% CI 71.4–100) respectively. Intensive program therapy in patients with CCSK allows to achieve satisfactory results of treatment.

In recent decades, there has been marked progress in understanding the biology of the most common extracranial solid tumor of childhood – neuroblastoma (NB), which led to a significant improvement in treatment outcomes due to stratification of patients into risk groups, intensification of treatment of patients with metastatic disease and the presence of unfavorable molecular genetic markers. Survivors who have received multimodal therapies, including chemotherapy, high-dose therapy and autologous peripheral stem-cell transplantation, 131I-metaiodobenzylguanidine (131I-MIBG) therapy, radiation therapy, and immunotherapy have a high risk of developing long-term side effects of treatment (LT SE). The study of the nature and frequency of LT SE after completion of therapy in patients with NB is important to ensure the quality of life and minimize severe health disorders. This article presents a literature review and description of a clinical case report of primary hypothyroidism in a high-risk patient with NB who received multicomponent treatment, including 131I-metaiodobenzylguanidine therapy due to the persistence of MIBG-positive foci after the induction chemotherapy.

In order to achieve good long-term results of combination treatment in children with malignant neoplasms, continuity of stages of the therapy and adherence to the time intervals between the stages are necessary. Severe accompanying pathology can make it difficult or impossible to complete all the necessary steps. The presented clinical case of a child with hepatoblastoma and Tetralogy of Fallot demonstrates the importance of the interdisciplinary work of oncologists, surgical oncologists and cardiac surgeons to ensure the optimal treatment algorithm for such patients.