Risk of malignant neoplasms in the first generation offspring of female workers of Mayak Production Association
The study of the role of parental preconception exposure in development of malignant neoplasms (MN) in the offspring is a topical point in cancerogenic factors’ research. The objective of the work is assessment of cancer risk among the offspring of female workers of the country’s first atomic production facility - Mayak Production Association (PA) - exposed to long-term occupational radiation exposure prior to conception. We have performed a retrospective epidemiological analysis in a cohort of offspring born in 1949-1990 that contained 2061 children from 1404 female workers. Mothers of 1145 children (55.6%) had accumulated doses of preconception external gamma-exposure to the ovaries (main group); the remaining 916 children (44.4%) were regarded as internal control (comparison group) as the offspring of female workers that were not exposed to preconception irradiation of genital organs. We have followed up the vital status and cancer incidence in the offspring up to 31.12.2018. We have performed an analysis of the structure and cancer incidence rates. We had calculated the relative risk (RR) and the excess relative risk (ERR) to a dose unit of external gamma-exposure with a 95% confidence interval using the AMFIT module of the EPICURE software. A total of 92 MN cases were registered in 1949-2018 among the first generation offspring of female workers. A comparative analysis of cancer incidence showed no significant difference in the structure and incidence rate of MN in the groups. The only exception were the offspring of the females not exposed to preconception occupational irradiation of genital organs; in this group we had indicated a significant increase of brain MN in male offspring and of the MN of corpus uteri among female offspring. We had registered MN of digestive organs and MN of breast most often in the main group of the offspring. The range of maternal doses of preconception external gamma-exposure to the ovaries varied greatly: maximum dose in male offspring reached 2954.82 mGy and 4075.61 in female offspring. Calculation of RR of MN in the offspring of the main group showed no significant difference from the comparison group for all the MN, for solid cancers separately, and for other most frequent cancers. Assessment of ERR coefficients in relation to maternal accumulated absorbed dose of preconception external gamma radiation to the ovaries had revealed no statistically significant increase of cancer incidence among the offspring of female workers exposed to occupational irradiation of genital organs. We had obtained no reliable evidence in our investigation of the relation between MN in the offspring of Mayak PA female workers and accumulated doses of preconception external gamma-exposure to the gonads. Further research is needed taking into account relatively young average age of the observed cohort of the offspring.