Treatment of lymphoblastic lymphomas in children in Russia: preliminary results of a multicenter retrospective study

Background. Lymphoblastic lymphomas (LBL) are an aggressive variant of non-Hodgkin’s lymphomas (NHL), which ranks second in frequency among non-Hodgkin’s lymphomas in children. According to international data, the effectiveness of LBL therapy in children reaches 85 %. In Russia, information on the treatment results for this disease is extremely limited. Aim. To present preliminary data on the results of LBL therapy in children in Russia. Materials and methods. The study included 392 pediatric LBL patients, treated in 57 specialized hospitals of the Russian Federation from 1999 to 2024. Results. The overall and event-free survival rates were 83 % (95 % confidence interval 78–88) and 70 % (95 % confidence interval 64–78), respectively. In addition, the analysis revealed a high frequency of thrombotic complications (29 % of all patients), especially in cases of T-cell LBL. No significant differences in disease outcomes were found between tumor immunophenotypes, the type of asparaginase, and the stage of the disease. A separate analysis of the results of LBL therapy according to the ALL IC-BFM 2002 / 2009 protocols (146 patients) with stricter criteria for the response to induction therapy (tumor reduction of more than 70 %) and early chemotherapy intensification with high-dose blocks at the N. N. Blokhin National Medical Research Center of Oncology showed the event-free and overall survival of about 90 %. The Cox regression model of the dependence of therapy outcomes on residual tumor volume at the end of induction in the main cohort of patients did not reveal an association between residual tumor volume and overall survival (p = 0.2), but there was a statistical association with event-free survival (p = 0.006). Discussion. This paper presents preliminary data from the first multicenter study of LBL therapy in pediatric patients in the Russian Federation. According to our data, LBL survival rates in the Russia should be improved. An important problem in the treatment of LBL in children is therapy complications, especially the high incidence of thrombosis. In this regard, anticoagulant prophylaxis is recommended for patients with LBL, especially with the T-cell phenotype and the presence of risk factors. Further studies are also needed to identify high-risk patients for the development of new personalized therapy approaches. Conclusion. The paper presents preliminary results from the first multicenter clinical study of LBL therapy in children in Russia, indicating the necessity of treatment approaches improvement for increase a treatment effectiveness.