Iron Overload as a Potential Predictor for Short Disease-Free Survival after Allogeneic Hematopoietic Stem Cell Transplantation in Acute Leukemia.

Abstract

Iron overload is associated with free radical generation and associated with an increase in toxic deaths after hematopoietic stem cell transplantation (HSCT). To evaluate pre-HSCT iron status influencing outcome and incidence of long-term complications, we analyzed 48 adult patients who underwent allogeneic HSCT for acute leukemia in the first complete remission (CR) status. We measured the iron status including serum iron, total iron binding capacity and serum ferritin in patients immediately before allogeneic HSCT. We defined iron overload prior to the HSCT as serum ferritin level ≥ 3000μg/L or transferrin saturation (TS) ≥ 100%. Seven (14.6%) cases were included in the iron overload group; five cases with ferritin level ≥ 3000 μg/L, two cases with TS ≥ 100%. Twenty-nine were the patients with acute myeloid leukemia (AML) and 19 were acute lymphoblastic leukemia (ALL). Thirty-five patients received the myeloablative conditioning regimen and 13 the reduced-intensity transplantation (NST). There were no significant differences in the rate of marrow engraftment and graft failure in relation to iron overload. The incidence of acute graft versus host disease (GVHD) and chronic GVHD in the iron overload group (14.3% and 42.8%, respectively) was not different compared to that in the non-overload group (46.3% and 34.1%, respectively). We analyzed the association between the iron overload and transplantation-related complications. There was no significant difference in the incidence of transplantation-related mortality and venocclusive disease between the two groups. The relapse rate after HSCT was higher in the iron overload group compared to control group (57.1% and 22.0%, respectively), although the statistical difference was not observed. The disease-free survival (DFS) rate at 24 months was significantly lower in the iron overload group (42.9%) compared to the non-overload group (65.6%, log rank test, P = 0.034). In conclusion, iron overload is considered to be one of the poor prognostic variables valid in the allogeneic HSCT settings. Iron chelation therapy before HSCT can be suggested for improving transplantation outcome.