Successful allografting for relapsing pediatric ALL: The results of two decades.

Abstract

e22000 Background: The prognosis of children and adolescents with acute lymphoblastic leukemia (ALL) has dramatically improved. This success is associated with both by multiagent chemotherapy regimens and by definition of clinical, biological and treatment response that allow the administration of risk-adapted therapy, including allogeneic hematopoietic stem cell transplantation (HSCT). In treatment of relapsed and resistance ALL, allogeneic HSCT continues to play a major curative role. In the present study, we desciribed the patients who underwent HSCT in our clinic in the last 21 years. Methods: From 1999 to 2020, 147 patients who diagnosed with ALL and treated with the COG protocols at the Istanbul University Oncology Institute were retrospectively reviewed and 17 of them relapsed. HSCT was applied 7 of the relapsed cases and also 3 resistant cases who had suitable matched donors. The demographic features, laboratory findings and treatment responses of 10 patients were recorded from the patients’ medical records. Results: All 10 patients were B-ALL with median diagnosis age of 79.5 months (range: 32-195) and 5 were male. Characteristics of patients given in Table 1. HSCT was performed due to late relaps in 7 patients. Three of the 7 relaps were only bone marrow and other 4 had combined. Patient #2 had both breast, conjunctiva and bone marrow for the 1st relaps and only conjunctiva for the 2nd one and this patient had also t(9;22) in the 1st relaps. Patient #3 had bone marrow+central nervous system relaps and patient #7 had bone marrow for the 1st relaps and testis and bone marrow for the 2nd one. Other 3 had poor response to treatment and Minimal Residual Disease (MRD) was high in End of Introduction (EoI) and End of Consolidation (EoC)). All patients had allogeneic HSCT and 8 are alive. Conclusions: HSCT remains the standard-of-care treatment for ALL patients who carry high-risk features predicting leukemia recurrence and for those experiencing high-risk first relapse or multiple relapses. Additionally, defining the indications of HSCT are dynamic and it could change according to treatment options as well as new molecular and biological findings. It is important to identify the patients who have high relapse risk and HSCT should have priority in patients whom MRD is high in EoI and EoC.[Table: see text]