Lessons from the atomic bomb about secondary MDS.

Myelodysplastic syndromes (MDSs) is a hematological neoplasm defined by ineffective hematopoiesis, dysplasia of hematopoietic cells, and risk of progression to acute leukemia. MDS occurs as de novo or secondary, and chemoradiotherapy for cancers is thought to increase the risk of MDS among patients. Recently, an epidemiological study for MDS among A-bomb survivors was performed, and it clearly demonstrated that the exposure to external radiation significantly increased the risk of MDS. Precise epidemiological data among survivors have revealed important clinical factors related to the risk of leukemias. In this review, by comparing data for secondary MDS and leukemia/MDS among survivors, several factors which would affect the risk of MDS, especially secondary MDS, are discussed.