Risk of developing hematological malignancies in the cohort of the East Urals radioactive trace

The article presents the first analysis of risk of developing hematological malignancies and leukemias in the cohort exposed to radiation in the area of the East Urals Radioactive Trace (EURT). Explosion of the container in the storage of radioactive wastes at the Mayak PO in 1957 and sedimentation of radioactive substances on adjusted areas caused irradiation of the general public. In 95% of the cohort members the total dose to the red bone marrow was less than 0.5 Gy, average radiation dose was 90 mGy. For 52 years after the accident (1957-2009) 76 hemoblastosis cases were registered in the cohort of 21373 members, among them 37 cases were diagnosed as leukemias including 8 CLL cases. Excess relative risk of developing hematological malignancies in the EURT cohort was 1.1 (95% CI: 0.08; 2.8) per 1 Gy of the total dose to the red bone marrow, as for leukemias incidence there was no statistically significant dose-response relationship. It is important to stress that risk for all cases of hemoblastosis and leukemia detected in the cohort became insignificant and close to 0 after exclusion of 1500 members from the analysis. These people were exposed to radiation in the area adjusted to the Techa river before the accident at the Mayak PO, the dose they got there significantly exceeded the dose got in the EURT area. According to analysis results it is possible to suggest that dose to the red bone marrow got by the public members in the EURT area only is not sufficient to detect statistically significant dose-response relationship, however, statistical power of the study can be increased, if the EURT cohort to be combined with the Techa river cohort.