2005 Volume 50 Issue Supplement1 Pages S97-S100
Myelodysplastic syndromes (MDS) are a heterogenous hematological group characterized by an ineffective hematopoiesis resulting in a variety of cytopenias, morphological abnormalities of blood cells, chromosomal aberrations, and an increases risk of transformation into acute myeloid leukemia. Despite of its nature of close relation to leukemia, MDS has been not well investigated in atomic bomb (A-bomb) survivors. We conducted a retrospective cohort study with over 80,000 A-bomb survivors in Nagasaki to assess the incidence of MDS and its relation with A-bomb exposure status. In a preliminary analysis, we confirmed 162 MDS cases during 1980 to 2004. The median age at diagnosis was 71 years old. The incidence rate was higher in men than women, and an inverse relationship was observed between incidence of MDS and the distance from the hypocenter. We suggest that A-bomb radiation may affect the occurrence of MDS in A-bomb survivors even more than 50 years passed after the explosion. Further detail analyses are necessary to confirm these results.