Clinical features and prognosis of patients with myelodysplastic syndromes who were exposed to atomic bomb radiation in Nagasaki.

Summary There is evidence that radiation exposureis a causative factor of myelodysplastic syndromes(MDS). However, little is known about whether radiation exposureis also a prognostic factor of MDS. We investigated the impact of radiation exposureon the prognosis of MDS occurred in Nagasaki atomic bombsurvivors, by allowing for the International Prognostic Scoring System(IPSS) and the revised version (IPSS-R). Subjects were 140 patients with primary MDS diagnosed during 1985–2011 and evaluable for IPSS, IPSS-R and exposure-distance. Of those, 31 were exposed at < 1.5 km; 35 at 1.5–2.99 km, and 74 at ≥ 3.0 km. By the end of March 2014, 47 patients (34%) progressed to overt leukemia and 106 (75.7%) died. By comparing with patients exposed at ≥ 3.0 km, those exposed at < 1.5 km had significantly higher frequencies of abnormal chromosome (P = 0.02), intermediate / poor IPSS, and intermediate / poor / very poor IPSS-R cytogeneticcategory (P = 0.0001, and P < 0.0001, respectively). As with de novo MDS, multivariate Cox regression analyses revealed that cytogeneticabnormalities, IPSS karyotype, and IPSS-R cytogeneticswere significantly associated with poor survival, and cumulative incidenceof leukemic transformation in MDS among atomic bombsurvivors, but exposure distance was not associated with any poor outcomes. These suggest that exposure to the greater dose of atomic bombradiation is associated with developing poor cytogeneticabnormalities in MDS, which might consequently lead to transform overt leukemia among atomic bombsurvivors. This article is protected by copyright. All rights reserved.