[Allogeneic transplantation for myelodysplastic syndromes: analyses of the Japanese registry data]

Myelodysplastic syndrome (MDS) is characterized by its frequent appearance in elderly patients, and allogeneic hematopoietic stem cell transplantation (HSCT) is the only curative therapy for MDS. However, the availability of HSCT depends on various factors, and it is possible that the HSCT outcomes may differ when compared on a country-by-country basis. Comparison of nationwide registry data from the US and Japan revealed that the two countries share a common trend of increasing the number of HSCT procedures from HLA-haploidentical relatives. However, the number of cord blood transplantation (CBT) procedures in the US is decreasing, whereas the number of those in Japan appears to be increasing. The results from the studies conducted by the adult MDS Working Group of the Japan Society for Hematopoietic Cell Transplantation revealed that the HSCT outcomes for elderly patients and for patients with intermediate cytogenetic risk and CBT in Japan were slightly superior to those in the United States and Europe. Because such differences in outcomes may be attributed to differences in patient backgrounds, it is preferable to establish "evidence" in one's own country. Although it is difficult to conduct a prospective study on rare diseases such as MDS, the use of a large-scale registry can provide an answer, even for such detailed clinical questions.