The role of registries in hematological disorders.

Hematopoietic cell transplantation (HCT) was developed more than 65 years ago to treat malignant blood disorders and irreversible bone marrow failures, with the aim of replacing a diseased hematopoietic system with a healthy one (allogeneic HCT). Decades later, the procedure was adapted to apply maximal chemotherapy or radiotherapy, which would result in bone marrow failure, but could be remedied by an infusion of a patient's own cryopreserved bone marrow (autologous HCT). Both treatments are high-risk and complex, especially during the initial phases. However, concerted efforts, vision, and collaboration between physicians and centers worldwide have resulted in HCT becoming a standard of care for many hematological disorders with progressive improvements in outcomes. Registries and the collaboration of societies worldwide have enabled the delivery of this curative therapy to many patients with fatal hematological diseases. More than 1.5 million HCT were performed between 1957 and 2019, and activity is continuously increasing worldwide.

Continuous and differential improvement in worldwide access to hematopoietic cell transplantation: activity has doubled in a decade with a notable increase in unrelated and non-identical related donors.

Promoting access to and excellence in hematopoietic cell transplantation (HCT) by collecting and disseminating data on global HCT activities is one of the principal activities of the Worldwide Network for Blood and Marrow Transplantation, a non-Governmental organization in working relations with the World Health Organization. HCT activities are recorded annually by member societies, national registries and individual centers including indication, donor type (allogeneic/autologous), donor match and stem cell source (bone marrow/peripheral blood stem cells/cord blood). In 2018, 1,768 HCT teams in 89 countries (six WHO regions) reported 93,105 (48,680 autologous and 44,425 allogeneic) HCT. Major indications were plasma cell disorders and lymphoma for autologous, and acute leukemias and MDS/MPN for allogeneic HCT. HCT number increased from 48,709 in 2007. Notable increases were seen for autoimmune diseases in autologous and hemoglobinopathies in allogeneic HCT. The number of allogeneic HCT more than doubled with significant changes in donor match. While HCT from HLA identical siblings has seen only limited growth, HCT from non-identical related donors showed significant increase worldwide. Strongest correlation between economic growth indicator of gross national income/capita and HCT activity/ten million population was observed for autologous HCT (r=0.79). HCT from unrelated donors showed strong correlation (r=0.68), but only moderate correlation (r=0.51) was detected from related donors. The use of HCT doubled in about a decade worldwide at different speed and with significant changes regarding donor match as a sign of improved access to HCT worldwide. Although narrowing, significant gaps remain between developing and non-developing countries.