Risk of solid cancer in the offspring of female workers of the Mayak nuclear facility in the Southern Urals, Russian Federation

Abstract

Studies of cancer risk following in utero exposure to ionizing radiation are limited in number, particularly for adult-onset cancers, and the evidence is unclear. In the present study, the risk of solid cancer incidence following in utero radiation exposure is examined among 8466 offspring of female nuclear workers at one of the largest nuclear facilities (Mayak Production Association) in the Russian Federation. Poisson regression methods were used to estimate excess relative risks (ERRs) per Gray (Gy). Mother's uterine gamma dose served as a surrogate for fetal gamma dose. During 277,002 person-years of follow-up (1948-2009), there were 177 first primary solid cancers excluding non-melanoma skin cancers. Estimated in utero gamma and plutonium doses exceeded zero for 41 and 23 % of offspring, respectively. Of the 177 solid cancers, 66 occurred among individuals with some in utero exposure to gamma radiation and 53 among those with estimated plutonium exposures. There was no indication of a statistically significantly increased risk of solid cancer incidence from in utero gamma exposure (linear ERR/Gy -1.0; upper 95 % confidence limit 0.5). This result was unchanged after accounting for subsequent occupational exposure. Plutonium doses were estimated but were too low to obtain meaningful risk estimates. Thus, in this cohort in utero radiation exposure was not associated with solid cancer risk. This is consistent with an earlier report of mortality in the cohort, but is based on twice as many cases and less susceptible to biases inherent in mortality analyses. Given the relatively young age of the cohort with respect to cancer, continued follow-up should be done as the number of cancer cases increases.

What do recent epidemiological studies tell us about the risk of cancer from radiation doses typical of diagnostic radiography?

“…Though based on only 2 cases and with an exceptionally wide confidence interval (-0.1, 1334), this latter finding is similar to that of the Oxford Survey or Childhood Cancers (OSCC) (ERR of 51 Gy -1 ) [58]. A later study by Tsareva and colleagues [56] focused on solid cancer incidence, with the advantage of longer follow-up and a greater number of cases. Again, no association with radiation exposure was found (ERR= -1.0 Gy -1 , 95% CI: N/A, 0.5).…”

“…Two recent studies have focused on the offspring of female workers at the Mayak nuclear facility in Russia, providing the opportunity to assess the lifetime cancer risks following in utero exposures. The median estimated in utero dose from gamma radiation for those with a dose greater than zero was 18.7 mSv (max= 945 mSv) [56]. Doses due to plutonium were extremely low.…”

Health Impacts of Low-Dose Ionizing Radiation: Current Scientific Debates and Regulatory Issues

“…No evidence was found that prenatal low-dose γ radiation exposure increased the risk of solid cancers or leukemia mortality in the 8000 offspring born of the Mayak female workers in 1948 to 1988. 113 The solid cancer incidence in the same offspring cohort (n = 8466) also did not differ from that in the general population 114 ; there was also no consistent association demonstrated between the risk of hematologic malignancies and plutonium exposure. 115 In a more recent study aimed to analyze cancer risk in a cohort of patients exposed in utero due to releases of nuclear waste into the Techa River in the Southern Urals (n = 10 482 for solid cancers, and n = 11 070 for hematological cancers), no association between in utero exposure and risk for both solid and hematological cancer was found.…”

“…A dose–response relationship between α-radiation exposure and incidence of various cancerous and noncancerous disorders was observed in nuclear workers chronically exposed by inhalation to plutonium ( 239 Pu) in the Mayak Nuclear Enterprise (Chelyabinsk region, Russia). 98 - 120 For instance, the incidence of lung cancer corrected for smoking was 0.56, 0.59, and 0.83 at body burdens of 343, 1180, and 4200 Bq, respectively, in 500 nuclear workers relative to internal controls. Of note, the lung cancer incidence was linearly associated with cigarette smoking, with 2-fold risk of lung cancer in those workers who smoked 1 pack of cigarettes per day for at least 5 years.…”

Incidence and Mortality of Solid Cancers in People Exposed In Utero to Ionizing Radiation: Pooled Analyses of Two Cohorts from the Southern Urals, Russia

“…The dose estimates for the MWOC did not take into account the contributions of 90 Sr and 137 Cs (mainly resulting from the nuclear accident in 1957), and 131 I (from Mayak PA airborne releases) to the exposures of mothers and their children due to residence in the city of Ozyorsk. Contributions from 239 Pu (received by mothers during their professional activities) were not considered in this analysis although available for a subset, but doses were low and no association was observed with solid cancer risk [ 14 ].…”