LAUSR

Allogeneic blood or marrow transplantation (BMT) is often used with curative intent to treat subgroups of childhood leukemia identified to be at a high risk of relapse [1–3]. However, there is limited information regarding overall and cause-specific late mortality experienced by children undergoing allogeneic BMT for leukemia [4–6]. We address this gap by conducting a detailed evaluation of late mortality, relapse-related mortality (RRM) and non-relapserelated mortality (NRM) among 2-year survivors after allogeneic BMT in childhood for acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML)/ myelodysplastic syndrome (MDS) and chronic myelogenous leukemia (CML). The Blood or Marrow Transplant Survivor Study-2 (BMTSS-2) is a collaborative effort between City of Hope (COH), University of Minnesota (UMN), and University of Alabama at Birmingham (UAB), examining long-term outcome after BMT. To be included in the present study, patients had to have received allogeneic BMT for ALL, AML, MDS or CML between 1974 and 2010 at COH or UMN, at age ≤ 21 years, and survived ≥ 2 years after transplantation. Information on type of leukemia, conditioning regimen, type of donor stem cells (related or unrelated), stem cell source, disease status at transplantation, graft vs. host disease (GvHD) prophylaxis, and demographic characteristics, was obtained from institutional transplant databases. National Death Index (NDI) Plus [7] and/or medical records provided information regarding the date and cause of death through 31 December 2015. Information from medical records and Accurint databases [8] was used to extend the vital status information through 31 December 2016. All patients were assigned a primary and, if present, a secondary cause of death. Human Subjects Committee at participating institutions approved the BMTSS-2 protocol. Informed consent was obtained in accordance with the Declaration of Helsinki. Kaplan–Meier techniques were used to describe overall survival, conditional on surviving ≥ 2 years from BMT. Standardized mortality ratio (SMR), a ratio of observed to expected number of deaths, was used to compare the mortality in this cohort to age(5-year interval), sex-, and calendar-specific mortality of the US general population [9]. Absolute excess risk (AER) was defined as the difference between the observed and expected number of deaths, per 1000 person-years of follow-up. Cumulative incidence rates * Smita Bhatia [email protected]