skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Thyroid nodularity and cancer among Chernobyl cleanup workers from Estonia

Abstract

Thyroid examinations, including palpation, ultrasound and, selectively, fine-needle aspiration biopsy, were conducted on nearly 2,000 Chernobyl cleanup workers from Estonia to evaluate the occurrence of thyroid cancer and nodular thyroid disease among men with protracted exposure to ionizing radiation. The examinations were conducted in four cities in Estonia during March-April 1995, 9 years after the reactor accident. The study population was selected from a predefined cohort of 4,833 cleanup workers from Estonia under surveillance for cancer incidence. These men had been sent to Chernobyl between 1986 and 1991 to entomb the damaged reactor, remove radioactive debris and perform related cleanup activities. A total of 2,997 men were invited for thyroid screening and 1,984 (66%) were examined. Estimates of radiation dose from external sources were obtained from military or other institutional records, and details about service dates and types of work performed while at Chernobyl were obtained from a self-administered questionnaire. Blood samples were collected for assay of chromosomal translocations in circulating lymphocytes and loss of expression of the glycophorin A (GPA) gene in erythrocytes. The primary outcome measure was the presence or absence of thyroid nodules as determined by the ultrasound examination. Of the screened workers, 1,247 (63%) were sentmore » to Chernobyl in 1986, including 603 (30%) sent in April or May, soon after the accident. Workers served at Chernobyl for an average of 3 months. The average age was 32 years at the time of arrival at Chernobyl and 40 years at the time of thyroid examination. The mean documented radiation dose from external sources was 10.8 cGy. Biological indicators of exposure showed low correlations with documented dose, but did not indicate that the mean dose for the population was higher than the average documented dose. 47 refs., 1 fig., 9 tabs.« less

Authors:
;  [1];  [2]
  1. National Cancer Inst., Rockville, MD (United States)
  2. Univ. of New Mexico, Albuquerque, NM (United States) [and others
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
433066
DOE Contract Number:
W-7405-ENG-48
Resource Type:
Journal Article
Resource Relation:
Journal Name: Radiation Research; Journal Volume: 147; Journal Issue: 2; Other Information: PBD: Feb 1997
Country of Publication:
United States
Language:
English
Subject:
56 BIOLOGY AND MEDICINE, APPLIED STUDIES; CHERNOBYLSK-4 REACTOR; DECONTAMINATION; THYROID; NEOPLASMS; MEN; BIOLOGICAL RADIATION EFFECTS; PERSONNEL; OCCUPATIONAL EXPOSURE; REMEDIAL ACTION; BIOLOGICAL INDICATORS; BIOPSY; BLOOD; ERYTHROCYTES; ESTONIA; LYMPHOCYTES; RADIATION DOSES

Citation Formats

Inskip, P.D., Boice, J.D. Jr., and Tekkel, M. Thyroid nodularity and cancer among Chernobyl cleanup workers from Estonia. United States: N. p., 1997. Web. doi:10.2307/3579424.
Inskip, P.D., Boice, J.D. Jr., & Tekkel, M. Thyroid nodularity and cancer among Chernobyl cleanup workers from Estonia. United States. doi:10.2307/3579424.
Inskip, P.D., Boice, J.D. Jr., and Tekkel, M. 1997. "Thyroid nodularity and cancer among Chernobyl cleanup workers from Estonia". United States. doi:10.2307/3579424.
@article{osti_433066,
title = {Thyroid nodularity and cancer among Chernobyl cleanup workers from Estonia},
author = {Inskip, P.D. and Boice, J.D. Jr. and Tekkel, M.},
abstractNote = {Thyroid examinations, including palpation, ultrasound and, selectively, fine-needle aspiration biopsy, were conducted on nearly 2,000 Chernobyl cleanup workers from Estonia to evaluate the occurrence of thyroid cancer and nodular thyroid disease among men with protracted exposure to ionizing radiation. The examinations were conducted in four cities in Estonia during March-April 1995, 9 years after the reactor accident. The study population was selected from a predefined cohort of 4,833 cleanup workers from Estonia under surveillance for cancer incidence. These men had been sent to Chernobyl between 1986 and 1991 to entomb the damaged reactor, remove radioactive debris and perform related cleanup activities. A total of 2,997 men were invited for thyroid screening and 1,984 (66%) were examined. Estimates of radiation dose from external sources were obtained from military or other institutional records, and details about service dates and types of work performed while at Chernobyl were obtained from a self-administered questionnaire. Blood samples were collected for assay of chromosomal translocations in circulating lymphocytes and loss of expression of the glycophorin A (GPA) gene in erythrocytes. The primary outcome measure was the presence or absence of thyroid nodules as determined by the ultrasound examination. Of the screened workers, 1,247 (63%) were sent to Chernobyl in 1986, including 603 (30%) sent in April or May, soon after the accident. Workers served at Chernobyl for an average of 3 months. The average age was 32 years at the time of arrival at Chernobyl and 40 years at the time of thyroid examination. The mean documented radiation dose from external sources was 10.8 cGy. Biological indicators of exposure showed low correlations with documented dose, but did not indicate that the mean dose for the population was higher than the average documented dose. 47 refs., 1 fig., 9 tabs.},
doi = {10.2307/3579424},
journal = {Radiation Research},
number = 2,
volume = 147,
place = {United States},
year = 1997,
month = 2
}
  • The reactor accident at Chernobyl in 1986 necessitated a massive environmental cleanup that involved over 600,000 workers from all 15 Republics of the former Soviet Union. To determine whether the whole-body radiation received by workers in the course of these decontamination activities resulted in a detectable biological response, over 1,500 blood samples were obtained from cleanup workers sent from two Baltic countries, Estonia and Latvia. Here we report the results of studies of biodosimetry using the glycophorin A (GPA) locus in vivo somatic cell mutation assay applied to 734 blood samples from these workers, to 51 control samples from unexposedmore » Baltic populations and to 94 samples from historical U.S. controls. The data reveal inconsistent evidence that the protracted radiation exposures received by these workers resulted in a significant dose-associated increase in GPA locus mutations compared with the controls. Taken together, these data suggest that the average radiation exposure to these workers does not greatly exceed 10 cGy, the minimum levels at which radiation effects might be detectable by the assay. Although the protracted nature of the exposure may have reduced the efficiency of induction of GPA locus mutations, it is likely that the estimated physical doses for these cleanup worker populations (median reported dose 9.5 cGy) were too low to result in radiation damage to erythroid stem cells that can be detected reliably by this method. 25 refs., 2 figs., 3 tabs.« less
  • A cohort of 4,472 men from Estonia who had participated in the cleanup activities in the Chernobyl area sometime between 1986 and 1991 and were followed through 1993 was analyzed with respect to the incidence of cancer and mortality. Incidence and mortality in the cleanup workers were assessed relative to national rates. No increases were found in all cancers (25 incident cases compared to 26.5 expected) or in leukemia (no cases observed, 1.0 expected). Incidence did not differ statistically significantly from expectation for any individual cancer site or type, though lung cancer and non-Hodgkin`s lymphoma both occurred slightly more oftenmore » than expected. A total of 144 deaths were observed [standardized mortality ratio (SMR) = 0.98; 95% confidence interval (CI) = 0.82-1.14] during an average of 6.5 years of follow-up. Twenty-eight deaths (19.4%) were suicides (SMR = 1.52; 95% CI = 1.01-2.19). Exposure to ionizing radiation while at Chernobyl has not caused a detectable increase in the incidence of cancer among cleanup workers from Estonia. At least for the short follow-up period, diseases directly attributable to radiation appear to be of relatively minor importance when compared with the substantial excess of deaths due to suicide. 28 refs., 3 tabs.« less
  • Thyroid nodularity following continuous low-dose radiation exposure in China was determined in 1,001 women aged 50-65 years who resided in areas of high background radiation (330 mR/yr) their entire lives, and in 1,005 comparison subjects exposed to normal levels of radiation (114 mR/yr). Cumulative doses to the thyroid were estimated to be of the order of 14 cGy and 5 cGy, respectively. Personal interviews and physical examinations were conducted, and measurements were made of serum thyroid hormone levels, urinary iodine concentrations, and chromosome aberrations in circulating lymphocytes. For all nodular disease, the prevalences in the high background and control areasmore » were 9.5% and 9.3%, respectively. For single nodules, the prevalences were 7.4% in the high background area and 6.6% in the control area (prevalence ratio = 1.13; 95% confidence interval = 0.82-1.55). There were no differences found in serum levels of thyroid hormones. Women in the high background region, however, had significantly lower concentrations of urinary iodine and significantly higher frequencies of stable and unstable chromosome aberrations. Increased intake of allium vegetables such as garlic and onions was associated with a decreased risk of nodular disease, which seems consistent with experimental studies suggesting that allium compounds can inhibit tumor growth and proliferation. The prevalence of mild diffuse goiter was higher in the high background radiation region, perhaps related to a low dietary intake of iodine. These data suggest that continuous exposure to low-level radiation throughout life is unlikely to appreciably increase the risk of thyroid cancer. However, such exposure may cause chromosomal damage.« less
  • Following the reactor accident at Chernobyl in late April of 1986, hundreds of thousands of men from throughout the former Soviet Union were sent to Chernobyl to entomb the damaged reactor, remove radioactive debris, and help decontaminate the local environment. They remained for an average of three months and were allowed to accumulate up to 25 cGy of radiation before being sent home. Doses for some workers may have exceeded the allowable limit. The experience of Chernobyl clean-up workers is potentially informative about cancer risk associated with protracted exposure to low levels of radiation. Cohorts of clean-up workers from themore » Baltic Republics were assembled for study, based on military records and other lists. The study population includes 4,833 men from Estonia 5,709 from Latvia and at least 5,446 from Lithuania, where a pilot study is underway. They are being monitored for cancer incidence through linkages with the corresponding national cancer registries. Biodosimetric assays, including fluorescent in situ hybridization (FISH) for chromosome translocation analysis and the glycophorin A (GPA) somatic cell mutation assay, are being used to supplement information about radiation doses from worker records and questionnaires. Thyroid screening examinations, including palpation, ultrasound and, selectively, fine-needle aspiration biopsies were performed on nearly 2,000 workers in the Estonian cohort (mean age, 40 y) during the spring of 1995, nine years after the reactor accident. The study is still in progress. Work began first in Estonia, and results presented here pertain to this subgroup except as otherwise noted. The average age at the time of arrival at Chernobyl was 31 years. 62% were sent in 1986. Possible reasons for the apparent absence or rarity of radiation-induced thyroid nodules include low and protracted doses, low susceptibility among men exposed as adults, and insufficient passage of time since the accident.« less
  • A cohort mortality study of white men employed for at least one year between 1939 and 1966 at three plants of a single United States company was conducted to evaluate the risk of lung cancer and nonmalignant respiratory disease among workers exposed to silica dust and nonfibrous (nonasbestiform) talc in the manufacture of ceramic plumbing fixtures. Follow-up of 2055 men through January 1, 1981, indicated a substantial excess of nonmalignant respiratory disease among those with high levels of exposure to silica dust (standardized mortality ratio = 2.26). The risk of nonmalignant respiratory disease rose with the number of years exposed,more » was not further enhanced by talc exposure, and appeared to be appreciably lower among those exposed in more recent time periods. For lung cancer, men exposed to high levels of silica dust with no talc exposure had a nonsignificant standardized mortality ratio of 1.37. However, those exposed to nonfibrous talc in addition to high levels of silica had a significant 2.5-fold excess risk of lung cancer. Among this group, the lung cancer standardized mortality ratio rose with increasing years of talc exposure to 3.64 among those exposed for 15 or more years. Although the role of silica as a cofactor cannot be ruled out, these data suggest that nonfibrous talc exposure is associated with excess lung cancer risk.« less