Effects of isolated central nervous system involvement evaluated by multiparameter flow cytometry prior to allografting on outcomes of patients with acute lymphoblastic leukemia

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains a major strategy to cure patients with acute lymphoblastic leukemia (ALL). The aim of this study was to evaluate whether isolated flow cytometry (FCM)-positive central nervous system (CNS) involvement before allo-HSCT is clinically significant. The effects of isolated FCM-positive CNS involvement prior to transplantation on the outcomes of 1406 ALL patients with complete remission (CR) were retrospectively investigated. Patients were classified into isolated FCM-positive CNS involvement (n=31), cytology-positive CNS involvement (n = 43), and negative CNS involvement (n = 1332) groups. Among the three groups, the 5-year cumulative incidence of relapse (CIR) values were 42.3%, 48.8%, and 23.4%, respectively (