Outcome Analysis of Pediatric Patients with Acute Lymphoblastic Leukemia Treated with Total Body Irradiation–Free Allogeneic Hematopoietic Stem Cell Transplantation: Comparison of Patients with and Without Central Nervous System Involvement

Abstract

Hematopoietic stem cell transplantation (HSCT) with a non-total body irradiation (TBI) conditioning regimen has proven feasible for treating patients with acute lymphoblastic leukemia (ALL). However, it is commonly believed that for extramedullary involvement of ALL in sanctuary sites, such as the central nervous system (CNS), TBI shall not be abandoned. In this study, the outcomes of pediatric ALL patients with CNS involvement (CNS) and without CNS involvement (CNS) treated with TBI-free allogeneic HSCT were retrospectively compared. The patients received a TBI-free busulfan plus cyclophosphamide conditioning regimen. Comparing CNS (n = 27) and CNS (n = 134) patients, the 5-year probabilities of relapse (44.4% versus 41.8%; P = .799), disease-free survival (DFS; 48.1% versus 43.3%; P = .642) and overall survival (OS; 51.9% versus 47.0%; P = .646) were not significantly different. Although transplantation-related mortality (TRM) was higher in the CNS patients, the difference between the 2 groups was not significant (3.7% versus 12.7%; P = .177). In multivariate analysis, there were no significant between-group differences in OS (P = .502), DFS (P = .424), relapse rate (P = .226), or TRM (P = .117). These findings suggest that HSCT using a non-TBI-containing conditioning regimen can lead to similar outcomes in pediatric ALL patients with and without CNS involvement. TBI-free allogeneic HSCT might be feasible and effective for CNS ALL patients.

Unexpected High Incidence of Human Herpesvirus-6 Encephalitis after Naive T Cell–Depleted Graft of Haploidentical Stem Cell Transplantation in Pediatric Patients

“…The rate of relapse was acceptable, mostly if we consider the high risk of leukemia types in our series and the fact that 2 of 3 patients who experienced relapse had active disease before the transplant. TRM was low, and the OS was comparable with the rates described in conventional transplantation from unrelated donors [39].…”

Long‐term brain status and cognitive impairment in children treated for high‐risk acute lymphoblastic leukemia with and without allogeneic hematopoietic stem cell transplantation: A single‐center study

“…In current treatment protocols, intensified chemotherapy has successfully replaced CNS‐RT without reducing the event‐free survival in many ALL patients 13 . Nevertheless, now it seems that radiotherapy given as CNS prophylaxis or as FTBI for conditioning before HSCT should not be abandoned in the group of HR ALL with the highest risk of relapse 14 …”

Allogeneic Hematopoietic Stem Cell Transplantation, Especially Haploidentical, May Improve Long-term Survival for Children With High-risk T-cell Acute Lymphoblastic Leukemia in First Complete Remission

“…However, the associated side effects were signi cant. Recently, HSCT without TBI has been proven effective for childhood ALL (Hamidieh, et al 2017). It has been demonstrated that central nervous system relapse of childhood ALL could be effectively prevented by risk-adjusted chemotherapy without cranial radiotherapy Vora 2015, Pui, et al 2009).…”