Characteristics and prognosis of central nervous system relapse after allogeneic hematopoietic stem cell transplantation in adult patients with leukemia.

Abstract

Central nervous system(CNS) is a common site of extramedullary involvement after allogeneic hematopoietic stem cell transplantation(allo-HSCT). It may confer inferior survival when combined with bone marrow(BM) relapse in leukemia patients. We performed a retrospective study to investigate the associated risk factors and prognosis in adult patients with post-transplant CNS relapse. Between 2016 and 2024 in our center, 74 leukemia patients developed CNS relapse after allo-HSCT, with 23 cases of isolated CNS(iCNS) relapse and 51 cases of combined CNS and BM(CNS&BM) relapse. Patients with CNS&BM relapse after allo-HSCT conferred inferior 5-year overall survival (OS) compared with those with iCNS relapse, and independent risk factors related with CNS&BM relapse were identified, including male gender(relative risk ratio[RR] = 4.09, 95% confidence interval [CI] = 1.29-13.02, p = 0.017), HLA-identical transplantation (RR = 4.11, 95% CI = 1.10-15.32, p = 0.035), and without chronic graft-versus-host disease occurrence (RR = 3.73, 95% CI = 1.00-13.84, p = 0.049). Early CNS relapse was identified as an independent predictor of worse 5-year OS from HSCT for patients with CNS&BM relapse (n = 51, <12 months after allo-HSCT, hazard ratio=7.35, p = 0.003). Systemic therapy after CNS relapse reduced subsequent BM relapse for ALL and CML patients (p = 0.038). These findings demonstrate the outcome of patients with post-transplant CNS&BM relapse remains very poor. HLA-haploindentical allo-HSCT and systemic therapy after CNS relapse may better reduce BM relapse.