Malignant pleural mesothelioma risk among nuclear workers: a review

Our plain-English summary of Malignant pleural mesothelioma risk among nuclear workers: a review, by C. Metz-Flamant, I. Guseva Canu, D. Laurier (Journal of Radiological Protection, 2011).

The study

• Authors: C. Metz-Flamant, I. Guseva Canu, D. Laurier
• Journal: Journal of Radiological Protection
• Published: 2011;31(1):9-23
• Type of article: Meta-analysis, Review
• Cited by: 17 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Exposure to ionising radiation has been suggested as a causal risk factor for malignant pleural mesothelioma (MPM). Studies of patients treated by radiotherapy for primary cancers have suggested that radiation contributes to the development of secondary MPM. Here we examined the risk to nuclear workers of MPM related to exposure to low doses of occupational radiation at low dose rates. All results concerning MPM risk in published studies of nuclear workers were examined for their association with radiation exposure and potential confounders. We found 19 relevant studies. Elevated risks of pleural cancer were reported in most (15/17) of these studies. Eight reported risks higher for radiation monitored workers than for other workers. However, of 12 studies that looked at associations with ionising radiation, only one reported a significant dose-risk association. Asbestos was an important confounder in most studies. We conclude that studies of nuclear workers have not detected an association between ionising radiation exposure and MPM. Further investigations should improve the consideration of asbestos exposure at the same time as they address the risk of MPM related to occupational exposure of nuclear workers to low doses of ionising radiation at low dose rates.

In plain English

This was a review of published studies of nuclear workers. It asked whether low doses of ionising radiation at work were linked to malignant pleural mesothelioma (MPM). The authors searched Medline and Scopus for 1980 to 2009 and found 19 relevant studies. Most of these studies reported 'pleural cancer' rather than MPM specifically, and the authors treated the two as equivalent. The risk of pleural cancer was elevated in 15 of 17 studies, and significantly so in nine. Eleven studies compared radiation-monitored workers with non-monitored workers, and eight of them reported higher risk in monitored workers. Twelve studies examined radiation dose. Only one of these found a significant dose-risk association (p = 0.01), and that result was driven by one case. Twelve of the 19 studies gave no information on asbestos. In one US study, a sub-cohort of asbestos workers had higher mortality from cancer of the pleura and peritoneum than other workers (standardised rate ratio 4.28; 1.19, 15.5). The authors concluded that there was not enough evidence of an association between MPM and low-dose occupational radiation. They also concluded that asbestos was likely to remain an important confounder.

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: Review of published epidemiological studies of nuclear workers (literature search of Medline and Scopus, 1980 to 2009)
• Who was studied: 19 published studies of nuclear workers reporting results for pleural cancer or MPM. The studies came from Australia, France, the United Kingdom and the United States, plus two international combined studies (3-country and 15-country). One study covered naval shipyard workers.
• Exposure: Low-dose occupational ionising radiation, mainly external doses. Average cumulative career-long external dose ranged from 8.3 to 130 mSv between studies. Asbestos (fiber type not specified) was assessed as a potential confounder.
• Main results:
  • Risk of pleural cancer was elevated in 15 of 17 studies, nine of which reported a significant excess.
  • Of eleven studies with risk estimates for both radiation and non-radiation workers, eight reported higher pleural cancer risk in radiation workers.
  • Of 12 studies with dose-response analyses or trend tests, only one (Springfields) reported a significant association between radiation dose and MPM (p = 0.01), driven by one case.
  • Only two studies quantified risk per dose (UK NRRW and the 15-country study). Both found an excess relative risk above 1 that was not statistically significant and had large confidence intervals. NRRW: 112 deaths, ERR/Sv 1.31 (90% CI -0.87 to 5.69).
  • Twelve of the 19 studies provided no information on potential asbestos exposure.
  • In the INEEL (US) study, cancer of the pleura and peritoneum occurred in 3 deaths among asbestos workers and 11 deaths among other workers. The standardised rate ratio for asbestos versus non-asbestos workers was 4.28 (1.19, 15.5).
  • At the French Areva NC Pierrelatte plant, all workers who died from MPM were exposed to asbestos according to the job-exposure matrix, and none had been monitored for external ionising radiation.
• The authors' conclusion: The authors concluded that there is not enough evidence from studies of nuclear workers to conclude that an association exists between MPM and occupational ionising radiation at low doses and low dose rates. They added that asbestos exposure is likely to remain an important confounder.
• Limitations the authors state:
  • Several of the available studies could not identify all cases of MPM with precision.
  • Pleural cancer was treated as equivalent to MPM in this review.
  • Most studies relied on death certificates without pathological confirmation of tumour type.
  • Most studies had very modest statistical power because of few MPM deaths.
  • Internal radiation doses were rarely estimated.
  • No published study estimated MPM risk from radiation while taking asbestos exposure into account.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma.

Medical terms in this study, explained in our Lexicon: Pleural Mesothelioma, Asbestos Exposure, Occupational Exposure.

Related studies

• Cancer mortality in relation to monitoring for radionuclide exposure in three UK nuclear industry workforces — L.M. Carpenter, C.D. Higgins, et al. (1998)
• Cancer risks and low-level radiation in U.S. shipyard workers — G.M. Matanoski, J.A. Tonascia, et al. (2008)
• Yield of Low-Dose Computerized Tomography Screening for Lung Cancer in High-Risk Workers: The Case of 7189 US Nuclear Weapons Workers — S.B. Markowitz, A. Manowitz, et al. (2018)
• Risk of cancer from occupational exposure to ionising radiation: retrospective cohort study of workers in France, the United Kingdom, and the United States (INWORKS) — D.B. Richardson, E. Cardis, et al. (2015)
• Solid cancer mortality associated with chronic external radiation exposure at the French atomic energy commission and nuclear fuel company — C. Metz-Flamant, E. Samson, et al. (2011)
• Mortality and cancer incidence of Australian participants in the British nuclear tests in Australia — R.T. Gun, J. Parsons, et al. (2008)

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