Prognosis and risk factors for central nervous system relapse after allogeneic hematopoietic stem cell transplantation in acute myeloid leukemia

We performed a nested case-control study to investigate the incidence, treatment, and prognosis of central nervous system (CNS) relapse after allogenic hematopoietic stem cell transplantation (allo-HSCT) for acute myeloid leukemia (AML) and compared the outcomes of patients with CNS relapse following haploidentical donor (HID) HSCT versus identical sibling donor (ISD) HSCT. A total of 37 patients (HID-HSCT, 24; ISD-HSCT, 13) developed CNS relapse after transplantation between January 2009 and January 2019, with an incidence of 1.81%. The median time from transplantation to CNS relapse was 239 days. Pre-HSCT CNS involvement (HR 6.940, 95% CI 3.146–15.306, p < .001) was an independent risk factor for CNS relapse after allo-HSCT for AML. The 3-year overall survival (OS) for patients with CNS relapse was 60.3 ± 8.8%, which was significantly lower than that in the controls (81.5 ± 4.5%, p = .003). The incidence of CNS relapse was 1.64% for patients who received HID-HSCT and 2.55% for those who received ISD-HSCT (p = .193). There was no significant difference in OS between the HID-HSCT and ISD-HSCT subgroups among the patients with CNS relapse. In conclusion, CNS relapse is a rare but serious complication after allo-HSCT for AML, and the incidence and outcomes of patients with CNS relapse are comparable following HID-HSCT and ISD-HSCT.