Managing the toxicity of hematopoietic stem cell transplant

Hematopoietic stem cell transplant is an established treatment modality for a variety of neoplastic, hematologic, and immunologic disorders. Fueled in part by remarkable technologic advances, the number of both autologous and allogeneic transplants has increased dramatically over the past decade. Peripheral blood stem cells have largely replaced bone marrow as the source of hematopoietic progenitors in autologous transplants, and their use in the allogeneic setting has increased substantially. Less toxic transplants, in the form of non-myeloablative conditioning regimens, are being actively investigated, with the promise of expanding indications and age limits for allogeneic transplant. A successful global infrastructure allowing sharing of HLA-typing information has led to increased availability of non-sibling, HLA-matched, unrelated donor transplants for many patients who lack a suitable sibling donor. Finally, umbilical cord blood transplants are being investigated in both children and adult patients. The ability to transplant more individuals with broader indications owes much to a concurrent improvement in supportive care agents and techniques. Although regimen-related mortality and morbidity have decreased, stem cell transplants continue to pose multiple potential complications. A careful proactive assessment to identify, treat, and, hopefully, prevent adverse events is essential to a successful transplant. This review is intended to summarize some of the toxicities of hematopoietic stem cell transplant in a systematic, organ-based fashion and to review the treatment options available for each of these side effects.