Impact of Nagasaki atomic bomb exposure on myelodysplastic syndrome patients who are treated with azacitidine.

BACKGROUND/AIM High-dose radiation exposure greatly increases the risk of myelodysplastic syndromes (MDS), however the clinical characteristics of MDS among atomic bomb survivors have not been thoroughly investigated to date. We designed this study to identify these characteristics. PATIENTS AND METHODS We retrospectively evaluated data from 13 atomic bomb survivors with MDS and 15 elderly patients with de novo MDS who were diagnosed between April 2011 and April 2013 at the Nagasaki Genbaku Hospital. All patients were treated with azacitidine (AZA; a hypomethylating agent) and overall survival rates were estimated. RESULTS No clear difference was observed in the clinical response to AZA between the two groups. However, atomic bomb survivors had a survival disadvantage, independent of their karyotype. CONCLUSION Minute genetic alterations caused by exposure to atomic radiation can adversely affect the response to AZA, even 66 years after the exposure. Further studies are required to clarify the mechanisms underlying this phenomenon.