William YK Hwang, Zhiyong Poon and Sudipto Bari
Over a million hematopoietic stem cell transplants (HSCTs) have been performed around the world for treatment of a range of cancers and hematological indications. A significant increase in transplants and transplant centers has been seen in many parts of the world, with the highest relative increase of transplant centers occurring in the Asia Pacific region, specifically in countries like China, India, Singapore and Thailand. The Bone Marrow Donors Worldwide (BMDW) register has grown to include over 20 million donors by 2013 with consequent greater ease in finding an unrelated donor for transplant. The availability of donors have been further enhanced through the use of alternate stem cell sources like cord blood and haploidentical donors. To protect donors while serving the needs of patients who are urgently seeking histocompatible donors in around the world, the World Marrow Donor Association (WMDA) has helped in establishing standards, accreditation, safety measures, shared processes and global monitoring systems for stem cell registries.
Recent developments in pre-transplant preparative regimens as well as post-transplant care have made incremental but definite improvements in post-transplant survival. Graft engineering has also helped to facilitate the removal of cells which cause graft-versus-host disease (GVHD), the eradication of cells which might cause relapse, the expansion of donor cells when there is an inadequate cell dose, and the addition of selected cells to improve graft function with augmented anti-tumor or anti-infective properties. These advances help enhance the safety, efficacy and availability of HSCT, ensuring that this modality of treatment remains an important part of the continuum of care of patients of potentially fatal cancers and blood diseases.