Outcome and Status of Microsatellite Stability in Japanese Atomic Bomb Survivors with Early Gastric Carcinoma

Abstract

In the decade after the 1945 atomic bombing of Hiroshima, a high incidence of leukemia was observed among atomic bomb survivors. However, the incidence of other cancers gradually increased, while that of leukemia decreased after this period. We evaluated the clinical outcome of early gastric cancer and microsatellite stability over a long-term period in atomic bomb survivors. The results of surgical treatment for early gastric cancer were reviewed for 117 atomic bomb survivors and 394 control patients between 1995 and 2006. In addition, immunohistochemical staining for hMSH2 and hMLH1 expression was performed to evaluate the status of microsatellite stability in 57 atomic bomb survivors and 82 control patients. The long-term survival rate for early gastric cancer in atomic bomb survivors was significantly lower than that in control patients (p<0.01). Multivariable analysis revealed that age and sex were significant and independent prognostic factors for early gastric cancer. Defective hMSH2 and/or hMLH1 expression was also significantly higher in survivors than in control patients (p<0.001). Logistic regression analysis revealed that atomic bomb survivorship was related to defective hMSH2 and/or hMLH1 expression. The prognosis of early gastric cancer in atomic bomb survivors was poor and was related to age and sex, rather than to being an atomic bomb survivor. Furthermore, a higher rate of defective hMSH2 and/or hMLH1 expression was observed in the survivors.