Cancer incidence among nuclear workers in Russia based on data from the Institute of Physics and Power Engineering: A preliminary analysis

One group that has the potential to be exposed to radiation is workers in t he nuclear industry. Results of a systematic medical follow-up and dosimetr ic monitoring of these workers can form the basis for a study of the relati onship between cancer incidence and radiation dose. As part of such efforts in Russia, a major institution of the nuclear industry with an established medical care unit, archiving capabilities, and dosimetry department was se lected: the Institute of Physics and Power Engineering (IPPE) in Obninsk. I n the study, a comparative e analysis of cancer incidence rates for the IPP E workers and for the general population of Russia in 1991-1997 was carried . out. The subjects were the IPPE workers hired before 1981. This restricti on was imposed to reduce the uncertainty associated with the possible laten t period in the development of solid cancers. Thus the possibility of inclu ding persons who already had the disease at the time when they were hired w as minimized. The analysis is based on information about 158 cancer cases, including 24 cancers in persons under individual dosimetric monitoring. A s tatistically significant excess in cancer incidence was found among the IPP E workers compared with a comparison population (the general population of Russia) for some types of cancers. The SIR values for all cancers (ICD-9: 1 40-208) is 0.93 (95% CI 0.76, 1.12) for males and 1.42 (95% CI 1.06, 1.87) for females. A statistically significant excess for all cancers was also ob served for residents of Obninsk compared to the control comparison populati on. The corresponding SIR value was 1.20 (95% CI 1.12, 1.28) for males and 1.58 (95% CI 1.49, 1.69) for females. An important reason for the observed excess in cancer incidence compared to the control population may be the hi gher level of health care in the so-called nuclear cities of Russia which m ay have resulted in increased diagnosis and registration of cancers. A stat istically significant dependence of the cancer incidence on the dor;e of io nizing radiation was not established. The excess relative risk per gray for all types of cancer was 0.91 (95% CI -2.75, 4.61) for males and 0.40 (95% CI -6.94, 7.83) for females. These estimates should be considered to be pre liminary, as the number of cases considered in the analysis of the dose res ponse is small (17 males and 7 females). (C) 2001 by Radiation Research Soc iety.