Haematopoietic stem cell transplantation outcomes for teenage and young adult patients with acute leukaemia: A British Society of Blood and Marrow Transplantation and Cellular Therapy registry study

Teenage and young adult (TYA) patients undergoing allogeneic stem cell transplant have distinct psychosocial needs, yet they are poorly represented in research and their outcomes are not well understood. This study uses prospectively collected data from the British Society of Blood and Marrow Transplantation and Cellular Therapy (BSBMTCT) registry to explore UK transplant practice and outcomes for TYA patients (aged 16-24) in this healthcare setting, alongside children (aged 1-15) and adults (aged 25-39), transplanted for acute leukaemia (including lymphoblastic, acute lymphoblastic leukaemia [ALL], and myeloid, acute myeloid leukaemia [AML]). Nine hundred and forty TYA patients, transplanted between 1999 and 2018, are included, representing 87% of all UK activity during the study period. On adjusted analyses, overall survival after transplant for ALL worsened from children, through TYA, to adults; survival for patients with AML was similar across age groups. Non-relapse mortality was not significantly worse in TYA patients compared with children (p = 0.117 in ALL, p = 0.379 in AML). The risk of chronic graft-versus-host disease (GvHD) was strongly correlated with age, with rates in the TYA group much closer to those seen in adults. While a graft-versus-leukaemia effect may be suppressing relapse, the high rate of GvHD represents an unmet need in this group, who are at a crucial juncture in their personal, educational and social development.