Treatment of Ewingʼs sarcoma in children and adolescents: new vision
Authors: Romantsova O. M. , Nisichenko D. V. , Khestanov D. B. , Khairullova V. V. , Dzampaev A. Z. , Kirgizov K. I. 
Published: October 2021

Introduction. Over the past decades, a significantly greater understanding of the morphology and molecular biological characteristics of tumors of the Ewing sarcoma family (ESFT) has been achieved. More than 70 % of relapses occur within 2 years from the date of diagnosis. In about 2/3 of cases, relapse occurs in distant places; this type of relapse is especially common in patients who initially have metastases. On the contrary, isolated local metastasis most often (in 1/5 of cases) occurs in patients with a localized form of the disease. In half of the patients, a relapse of the disease was detected during a routine examination, was asymptomatic and was a chance find.Purpose of the study – to evaluate the effectiveness of anti-relapse treatment in patients with ESFT, to develop an algorithm for a personalized approach, to improve the results of overall and relapse-free survival in children and adolescents with ESFT.Materials and methods. Our study included patients with a confirmed diagnosis of Ewing sarcoma (ES), who received treatment from 2008 to 2019. The analysis of follow-up data was closed on 19.02.2021. The study included 274 patients aged 6 months to 18 years, the average age was 11.6 years. Up to 1 year in our study there were 2 children. Twelve (4.3 %) patients went out of follow-up within 2 to 9 months from the start of treatment; we did not include them in the subsequent analysis. Analyzed were 262 patients with ES who received treatment according to the protocols at the Research Institute of Pediatric Oncology and Hematology of the N.N. Blokhin National Medical Research Center of Oncology. A relapse of the disease was revealed in 48 (18.3 %) children out of 262 – the study group; 58 (22.1 %) patients showed disease progression during treatment. In 70.8 % (34/48) patients had an isolated relapse, in 14 (29.2 %) cases – a combined one. The defeat of only the lung tissue with a relapse of the disease occurred in 19/48 (39.6 %) cases, local relapse without metastasis – 7/48 (14.5 %) cases. In general metastatic lung disease occurred in 66.6 % of cases. The defeat of the brain and lymph nodes occurred in 4 %. Most of the patients were in the group from 11 to 17 years, inclusive – 38/48 patients, which amounted to 79 %. All 48 patients from the study group received anti-relapse therapy depending on the duration of the disease relapse. For late relapses the primary treatment regimen was used: alternating courses of chemotherapy with vincristine/doxorubicin/cyclophosphamide and etoposide/ifosfamide. In early relapses two regimens were most used: vincristine/topotecan/cyclophosphamide and vincristine/irinotecan/temozolomide (VIT). The positive response rate with the antirelapse VIT regimen was 60 %, and the time to progression was 7.6 months. With the topotecan regimen the response rate was 45 % and the time to progression – 7 months.Results. The overall survival (OS) rate of patients when a relapse was detected was significantly (p £ 0.05) higher when compared with the group of patients who had progression of the disease, which is associated with the effect of anti-relapse chemotherapy. When analyzing OS of patients with ES it should be noted that the 5-year survival rate of all patients (n = 262) was 66.3 ± 3.3 %, compared with the group of patients with confirmed relapse (n = 48) – 53 ± 8.1 %. The median in the group of patients with relapse was 39.3 months. The follow-up time in the group with recurrent ES disease averaged 52.2 ± 32.3 months (from 12.6 to 142 months). OS of patients was analyzed depending on the interval of disease recurrence. The Interval No. 1 was from the beginning of the main treatment to the first relapse, with a median of 37.2 months. Interval No. 2 – from the date of the first relapse to the date of the second relapse with a follow-up time of 58.8 ± 29.1 months (from 28.6 to 108 months), the median was not reached. The second relapse occurred significantly less frequently than the first relapse (p = 0.000001).Conclusion. The outcome for patients with recurrent ES remains poor, and a standard approach to their treatment has not yet been established. Standard first and second lines chemotherapy can be effective in most patients in terms of reducing symptoms and increasing the time to further progression, but complete remission remains hard to reach. Further multidisciplinary study of prognostic factors, effects of various treatment regimens and protocols, study of the inclusion of targeted drugs in the therapy program is required.