Cancer incidence among Australian nuclear industry workers

Our plain-English summary of Cancer incidence among Australian nuclear industry workers, by R.R. Habib, S.M. Abdallah, M. Law, et al (Journal of Occupational Health, 2006).

The study

• Authors: R.R. Habib, S.M. Abdallah, M. Law, J. Kaldor
• Journal: Journal of Occupational Health
• Published: 2006;48(5):358-65
• Cited by: 12 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

To assess whether workers at Lucas Heights Science and Technology Centre (LHSTC) had different levels of cancer incidence from the New South Wales (NSW) population in Australia. A retrospective cohort study was undertaken at LHSTC. Data on 7,076 workers employed between 1957-98 were abstracted from personnel, dosimetry, and medical files. An inception cohort was defined which included 4,523 workers in employment between 1972-96 to examine cancer incidence. Cancer registrations in the inception cohort were identified to 1996 through electronic linkage of records with the NSW and the Australian national registers of cancer incidence. All-cancer incidence in workers at LHSTC was 15% below the NSW rates [SIR=0.85; 95% CI=(0.75, 0.95)]. Of 37 specific cancers and groups of cancers examined, statistically significant excesses relative to NSW rates were observed only for pleural cancer incidence [SIR=17.71; 95%=(7.96, 39.43)], and for incidence of cancer of the small intestine [SIR=4.34; 95% CI=(1.40, 13.46)]. This study gives little evidence of an increased risk of cancers associated with radiation exposure in a cohort of nuclear workers in Australia. The observed increase in the risk of cancer of the pleura was probably due to unmeasured exposures, given the lack of an established association with radiation exposure, and the strong link to asbestos exposure. Findings for cancers of the small intestine were based on small numbers and were likely to be due to chance.

In plain English

This retrospective cohort study compared cancer rates among workers at the Lucas Heights Science and Technology Centre with rates in the general New South Wales (NSW) population. Of 7,076 workers employed 1957 to 1998, the 4,523 employed in 1972 to 1996 were linked to cancer registers up to 1996. Overall, workers had 263 cancers against 311.19 expected, a standardised incidence ratio (SIR) of 0.85 (95% CI 0.75 to 0.95). Cancer of the pleura and other thoracic organs was raised: 6 cases against 0.34 expected (SIR 17.71; 95% CI 7.96 to 39.43). The excess appeared in both radiation-monitored and non-monitored workers. Small intestine cancer was also raised (3 cases; SIR 4.34; 95% CI 1.40 to 13.46), while lung cancer was lower than expected. The authors believed the pleural excess was probably due to unmeasured exposures such as asbestos. They said the small-intestine finding may be due to chance. They concluded the study gave little evidence of increased cancer risk compared with NSW. They noted that occupational and lifestyle factors, including smoking, were not accounted for and that case numbers were small.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Retrospective cohort study comparing cancer incidence with general-population (NSW) rates using standardised incidence ratios
• Who was studied: Workers at Lucas Heights Science and Technology Centre (LHSTC), New South Wales, Australia. 7,076 workers were employed 1957 to 1998. The analysed inception cohort was 4,523 workers employed between 1972 and 1996, followed for cancer to 1996.
• Exposure: Ionising radiation at a nuclear research site. Workers were classed as monitored (film badges) or non-monitored for radiation. Non-monitored workers were assumed unexposed. Average cumulative external photon dose in monitored workers was 15.04 mSv. Asbestos exposure was not measured.
• Main results:
  • All workers combined had all-cancer incidence 15% below NSW rates: 263 observed versus 311.19 expected, SIR 0.85 (95% CI 0.75, 0.95).
  • Cancer of the pleura and other thoracic organs was in excess in all workers combined: 6 observed versus 0.34 expected, SIR 17.71 (95% CI 7.96, 39.43).
  • The pleural excess appeared in both groups. Non-monitored workers had SIR 19.21 (95% CI 4.80, 76.81). Monitored workers had SIR 17.05 (95% CI 6.40, 45.42).
  • The authors attributed the pleural excess, in their belief, probably to unmeasured exposures in the cohort such as asbestos.
  • Cancer of the small intestine was elevated in all workers combined: 3 observed versus 0.69 expected, SIR 4.34 (95% CI 1.40, 13.46). All 3 cases were in monitored workers.
  • Lung cancer was lower than NSW rates in all workers combined: 25 observed versus 43.72 expected, SIR 0.57 (95% CI 0.39, 0.85).
  • The SIR for radiosensitive solid cancers was 0.85 in both monitored and non-monitored workers. Neither result was statistically significant.
• The authors' conclusion: The authors concluded that the analysis gave little evidence of an increased risk of cancers in the LHSTC cohort compared with the NSW population. They said the small-intestine excess was unexpected and may be a chance finding.
• Limitations the authors state:
  • Occupational and lifestyle risk factors were not accounted for and may have confounded results.
  • No smoking data were available, so confounding by smoking could not be assessed.
  • Registry linkage may have been incomplete. In particular, it missed cancers diagnosed and registered outside NSW between 1972 and 1981.
  • The small number of cases limited precision for specific cancers.
  • The relatively short follow-up did not allow detection of long-latency cancers among recently employed workers.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Power plants and utilities.

Medical terms in this study, explained in our Lexicon: Cohort Study, Pleura, Asbestos Exposure.

Related studies

• Mortality rates among nuclear industry workers at Lucas Heights Science and Technology Centre — R.R. Habib, S.M. Abdallah, et al. (2005)
• Update of mortality and cancer incidence in the Australian petroleum industry cohort — R.T. Gun, N. Pratt, et al. (2006)
• Update of a prospective study of mortality and cancer incidence in the Australian petroleum industry — R.T. Gun, N.L. Pratt, et al. (2004)
• Risk of cancer among Danish utility workers--a nationwide cohort study — C. Johansen, J.H. Olsen (1998)
• Cancer incidence among Minnesota taconite mining industry workers — E.M. Allen, B.H. Alexander, et al. (2015)
• Occupational respiratory cancer and exposure to asbestos: a case-control study in a cohort of workers in the electricity and gas industry — E. Imbernon, M. Goldberg, et al. (1995)

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