Immunological and cytogenetic features, treatment management and prognosis in pediatric relapsed/refractory leukemias

Abstract

Author(s): Huseyin Avni Solgun*, Duygu Ozkorucu Yıldırgan, Ozlem Terzi and Cengiz Bayram

Background: Relapsed Acute Lymphoblastic Leukemia (ALL) has remained challenging to treat in children with survival rates lagging well behind those observed at initial diagnosis. Although there have been some improvements in outcomes over the past few decades, only approximately 50% of children with first relapse of ALL survive long term, and outcome are much worse with second or later relapses. Material and Methods: In this study, 24 Patients who received leukemia treatment in the pediatric hematology and oncology clinic of our hospital between the years 2020-2023 and were diagnosed as refractory or relapsed were included. Diagnostic and treatment information such as immunophenotype, cytogenetics, treatment protocols, relapse treatment protocols, demographic data, relapse characteristics of the patients were recorded in patient-specific sheets. Considering these data, the survival rates of the patients and the response rates to the treatments were presented. Results: A total of 24 patients, 7 of them were girls (29%), 17 of them were boys (71%). 19 of the patients were ALL (5 T-ALL, 14 B-ALL) and 5 AML. The mean age at primary diagnosis of the patients was 7.04 years ± 4.51 years, and the mean age at relapse was 8.77 years ± 4.31 years. The relapse times of the patients were 7 very early (30%), 7 early (30), 8 late (32%) relapse, 2 (8%) patients who could not achieve remission. The relapse times of the patients were 7 very early (30%), 7 early (30), 8 late (32%) relapse, 2 (8%) patients who could not achieve remission. At the time of relapse, 7 (30%) of the patients were in the standard risk group and 17 (70%) were in the high-risk group. Isolated bone marrow 16 (66%), Isolated Cerebrospinal Fluid (CSF) 4 (17%), isolated testis 1 (4%), and bone marrow and CSF 3 (13%) were relapsed. In cytogenetic studies, t9.22 gene mutations were found in 4 (17%) patients, complex karyotype in 2 (8%) and FLIT3 gene mutations in 1 (4%). Conclusion: Until recently, the main treatment options for relapsed ALL were cytotoxic chemotherapy and HSCT. Now there are a variety of treatment options, including highly active immunotherapies for B-ALL, small molecule inhibitors of pathways altered in relapsed T-ALL, and improved HSCT technologies. Risk stratification has been further refined at initial diagnosis and some of these therapies are now also being investigated. Future efforts will sustain the best choices for better porgnostic outcome of Pediatric Leukemias.

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