Late Effects after Allogeneic Hematopoietic Stem Cell Transplantation

Worldwide, greater than 60 000 people undergo hematopoietic stem cell transplantation (HSCT) annually. Since the inception of HSCT in the treatment paradigm of human diseases approximately 50 years ago, substantial advances in HSCT techniques and supportive care have led to improvements in survival, but late effects of HSCT cause substantial morbidity and mortality. In the case of allogeneic HSCTs, immunosuppressive therapies and graft-versus-host disease are major contributors to these complications. The majority of the complications occur within a few years of allogeneic-HSCT; however the incidence of a few conditions (e.g., cardiovascular complications and secondary cancers) is highest at 6-10 years post-HSCT. Thus, these complications can be broadly divided into late effects (occurring after 6 months of HSCT) and very late effects (occurring after 5 years of HSCT). Management of specific late effects is discussed separately. The goals of this chapter include a comprehension of the basic concepts and identification of these effects.