Allogeneic Hematopoietic Cell Transplantation in Children with Relapsed Acute Lymphoblastic Leukemia Isolated to the Central Nervous System

Complications following HCT. (A) TRM. The cumulative incidence of TRM for pediatric patients undergoing HCT for ALL was lowest for patients with isolated CNS relapse (CNS: 0; P = .03), versus patients with bone marrow relapse (BM: 19%; CI: 11%-27%) or combined marrow and CNS relapse (BM + CNS: 29%; CI: 8%-51%). (B) Acute GVHD. The cumulative incidence of stage II-IV aGVHD was not significantly different between patients with isolated CNS relapse (CNS: 51% CI: 24%-78%), bone marrow relapse (BM: 36%; CI: 26%-47%), or combined marrow and CNS relapse (BM + CNS: 18% CI: 0%-35%).

Outcomes following HCT. (A) Relapse. The cumulative incidence of 2 year posttransplant relapse for pediatric patients undergoing HCT for relapsed ALL was lowest for patients with isolated CNS relapse (CNS: 0%; P = .01) when compared with patients with bone marrow relapse (BM: 30%; CI: 20%-41%) or combined marrow and CNS relapse (BM + CNS: 12%; CI: 0%-27%). (B) EFS. Kaplan-Meier estimates of the probability of 5-year EFS of pediatric patients undergoing HCT for ALL were highest for patients with isolated CNS relapse (CNS: 91% CI: 51%-99%; ∗P < .01), compared with patients with bone marrow relapse (BM: 35%; CI: 25%-45%), or combined marrow and CNS relapse (BM + CNS: 46%, CI: 22%-68%). (C) OS. Kaplan-Meier estimates of the probability of 5-year OS of pediatric patients undergoing HCT for ALL with isolated CNS relapse (CNS: 86% CI: 33%-98%), bone marrow relapse (BM: 38%; CI: 27%-49%) or combined marrow and CNS relapse (BM + CNS: 53%, CI: 28%-73%) (∗P < .01).