Ultra-low-dose chest computer tomography screening of an asbestos-exposed population in Western Australia

Our plain-English summary of Ultra-low-dose chest computer tomography screening of an asbestos-exposed population in Western Australia, by F.J. Brims, C.P. Murray, N. de Klerk, et al (American Journal of Respiratory and Critical Care Medicine, 2015).

The study

• Authors: F.J. Brims, C.P. Murray, N. de Klerk, H. Alfonso, A. Reid, D. Manners, P.M. Wong, J. Teh, N. Olsen, R. Mina, A.W. Musk
• Journal: American Journal of Respiratory and Critical Care Medicine
• Published: 2015;191(1):113-6
• Type of article: Letter
• Cited by: 23 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Summary of the article

This research letter reported the results of offering ultra-low-dose chest computed tomography (LDCT) to people with past asbestos exposure in Western Australia. The authors asked whether such screening detected lung cancer and whether existing screening guidelines would have identified those at risk. Over a 12-month period, participants in the Western Australia Asbestos Review Program were offered LDCT instead of annual plain chest radiography. To be in the program, participants needed at least 3 months of occupational asbestos exposure and/or radiographically confirmed pleural plaques. Of 1,308 participants, 906 chose LDCT. Their mean age was 68.8 years, 83.6% were male, and 62.8% were ever-smokers with a mean of 17.1 pack-years. Scans were scored by thoracic radiologists using the NELSON trial method. Significant nodules were reported in 77 participants (8.4%). Seven lung cancers were found, a prevalence of 0.77%. Six were stage Ia and one stage IIa, and all were treated with surgery with curative intent. Using those who declined LDCT as a comparator, sensitivity was 100%, specificity 92.0% and positive predictive value 8.86%. Only 33 participants (3.6%) would have been eligible for screening under US Preventive Services Task Force criteria and 269 (29.7%) under NCCN guidelines. None of the seven cancer cases would have met the Task Force criteria, and two would have met the NCCN guidelines. The authors concluded that current guidelines may not adequately account for asbestos-related lung cancer risk. They called for risk prediction models that incorporate asbestos exposure.

PubMed has no abstract for this study, and the article doesn't print one. We wrote this summary from the full article with the help of AI. It is not the authors' wording.

In plain English

This research letter described a 12-month program in which participants in the Western Australia Asbestos Review Program were offered low-dose chest CT instead of their annual plain chest X-ray. To join the program, people needed at least 3 months of occupational asbestos exposure and/or pleural plaques confirmed on X-ray. Some had worked or lived at Wittenoom, a crocidolite asbestos mine and township. Of 1,308 participants, 906 chose CT. Significant lung nodules were reported in 77 (8.4%), who were recalled for an earlier scan. Seven people in the CT group had lung cancer, a prevalence of 0.77%. Six had stage Ia disease and one stage IIa, and all had surgery with curative intent. Only 62.8% of the CT group had ever smoked. None of the seven would have qualified for screening under US Preventive Task Force criteria, and two would have qualified under NCCN guidelines. The authors concluded that the results suggest people with significant occupational asbestos exposure are at elevated lung cancer risk. They said the small number of cases meant they could not measure the link between asbestos exposure and lung cancer risk.

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: Research letter (correspondence) reporting the results of a low-dose CT lung cancer screening offer within an existing asbestos review program, compared with participants who declined CT
• Who was studied: 1,308 participants of the Western Australia Asbestos Review Program. 906 chose low-dose CT and 402 did not. In the CT group, 758 (83.6%) were male and the mean age was 68.8 years.
• Exposure: At least 3 months of occupational asbestos exposure and/or radiographically confirmed pleural plaques. The CT group included 136 (16.0%) Wittenoom workers, 206 (24.3%) Wittenoom residents and 507 (59.7%) people with other occupational exposure. Wittenoom was a crocidolite asbestos mine and township that operated from 1946 to 1966.
• Main results:
  • Significant nodules were reported in 77 (8.4%) of the CT participants, who were recalled for an interval CT ahead of the planned annual screen.
  • Seven CT participants were found to have lung cancer. Six had stage Ia disease and one stage IIa, and all underwent surgery with curative intent. The table lists 0 lung cancers in the group that declined CT.
  • The prevalence of lung cancer in the CT cohort was 0.77%, although only 62.8% of that cohort had ever smoked, with a mean tobacco history of 17.1 pack-years.
  • Using participants who declined CT as the comparator, CT had a sensitivity of 100%, specificity of 92.0%, positive predictive value of 8.86% and negative predictive value of 100%. The false-positive rate was 91.1%.
  • Of the 906 CT participants, 33 (3.6%) would have been eligible for screening under US Preventive Task Force criteria and 269 (29.7%) under NCCN guidelines. Of the seven people with lung cancer, none would have been eligible under the Task Force criteria and two under NCCN guidelines.
• The authors' conclusion: The authors concluded that the results suggest individuals with significant occupational asbestos exposure are at elevated risk for lung cancer. They said lung cancer risk prediction models need to account for a history of asbestos exposure.
• Limitations the authors state:
  • The small number of cases meant the authors could not quantify the association between lung cancer risk and asbestos exposure.
  • The population had been prescreened with plain chest X-rays at least 1 year earlier, which may have lowered the prevalence of lung cancer found by CT.
  • Some screen-detected lung cancers may have been overdiagnosed.

Mines named here

Asbestos mines this study is about. Each mine's page says who ran it, when it worked, and what it produced.

• Wittenoom, Western Australia

All asbestos mines

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestosis, Lung cancer.

Medical terms in this study, explained in our Lexicon: Asbestos Exposure, Lung Cancer, Pleural Plaques, Stage IA.

Related studies

• Ultra low dose CT screen-detected non-malignant incidental findings in the Western Australian Asbestos Review Programme — C.P. Murray, P.M. Wong, et al. (2016)
• Correlation of ultra-low dose chest CT findings with physiologic measures of asbestosis — D. Manners, P. Wong, et al. (2017)
• Diagnostic Performance of Ultra-Low-Dose Computed Tomography for Detecting Asbestos-Related Pleuropulmonary Diseases: Prospective Study in a Screening Setting — M. Schaal, F. Severac, et al. (2016)
• Low-dose chest computed tomography screening of subjects exposed to asbestos — K. Kato, K. Gemba, et al. (2018)
• Effects of asbestos and smoking on the levels and rates of change of lung function in a crocidolite exposed cohort in Western Australia — H.S. Alfonso, L. Fritschi, et al. (2004)
• Impact of low-dose computed tomography screening on lung cancer mortality among asbestos-exposed workers — F. Barbone, F. Barbiero, et al. (2018)

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