Comparison of x-ray films and low-dose computed tomographic scans: demonstration of asbestos-related changes in 2760 nuclear weapons workers screened for lung cancer

Our plain-English summary of Comparison of x-ray films and low-dose computed tomographic scans: demonstration of asbestos-related changes in 2760 nuclear weapons workers screened for lung cancer, by A. Miller, S.A. Widman, J.A. Miller, et al (Journal of Occupational and Environmental Medicine, 2013).

The study

• Authors: A. Miller, S.A. Widman, J.A. Miller, A. Manowitz, S.B. Markowitz
• Journal: Journal of Occupational and Environmental Medicine
• Published: 2013;55(7):741-5
• Cited by: 18 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Objective: Increased availability and technical improvements of computed tomographic (CT) scanning encourages its use for detecting asbestos-related disease. We compared low-dose scans and x-ray films in 2760 workers potentially exposed to asbestos, to assess their ability to detect interstitial lung disease (ILD) and pleural thickening (PT).

Methods: A total of 2760 nuclear workers received radiography and CT scanning (2006 to 2009). X-ray films were read by a B reader for ILD and PT and CT scans by a thoracic radiologist, using a protocol for nodules, ILD, and PT.

Results: Of the 2760 workers, 271 showed circumscribed PT on CT scans, and 73 on x-ray films, 54 (74%) of which were confirmed on CT scans; 76 showed ILD on CT scans, and 15 on x-ray film, 10 (67%) of which were confirmed on CT scans.

Conclusions: Radiographic readings of PT and ILD were generally confirmed on CT scans. Computed tomographic scans detected three to five times more cases; the majority were minor.

In plain English

This study compared chest x-rays with low-dose CT scans, done for lung cancer screening between 2006 and 2009, in 2760 retired and active nuclear weapons workers with likely asbestos exposure. One B reader read the x-rays and one thoracic radiologist read the CT scans, looking for circumscribed pleural thickening (plaques) and interstitial lung disease. CT scans showed pleural thickening in 271 workers and x-rays in 73. Of those 73, 54 (74%) were confirmed on CT. CT showed interstitial lung disease in 76 workers and x-rays in 15. Of those 15, 10 (66.7%) were confirmed on CT. Many findings seen only on CT were described as minor, early or minimal. CT showed interstitial lung disease in 3 of 18 workers whose x-rays were read 0/1 (classed as normal), and in 10 of 15 whose x-rays were read 1/0 or greater (classed as abnormal). The authors concluded that x-ray readings were generally confirmed by CT, and that CT found three to five times more cases, most of them minor. Each method was read by a single physician, and no exposure measurements were made.

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: Comparison of two imaging methods (chest x-ray films versus low-dose CT scans) in the same workers, using an ongoing lung cancer screening program
• Who was studied: 2760 retired and active nuclear weapons workers aged 45 or older (2335 men, 425 women), imaged between 2006 and 2009. X-ray films were made at local clinics in Tennessee, Kentucky and Ohio.
• Exposure: Likely asbestos exposure from equipment, pipes and ducts of gaseous diffusion plants and other nuclear fuel production facilities. Workers were mostly in production, engineering and maintenance jobs. No fiber type is named and no individual exposure measures were available.
• Main results:
  • Pleural thickening: 271 of 2760 workers (9.8%) on CT scans and 73 (2.6%) on x-ray films. Of the 73 x-ray cases, 54 (74%) were confirmed on CT.
  • Interstitial lung disease: 76 workers on CT scans and 15 on x-ray films. Of the 15 x-ray cases, 10 (66.7%) were confirmed on CT.
  • Compared with CT for pleural thickening, chest x-ray had sensitivity 19.7%, specificity 99.2%, positive predictive value 74.0% and negative predictive value 91.8%.
  • Compared with CT for interstitial lung disease, chest x-ray had sensitivity 13.2% and specificity 99.8%.
  • Of 203 pleural thickening cases seen only on CT and attributed to asbestos exposure, 110 (54%) were called minor by the radiologist.
  • Of interstitial lung disease cases seen only on CT, most (73%, n = 45) were described as early or minimal.
  • Interstitial lung disease was shown on CT in 3 of 18 workers (17%) with an x-ray reading of 0/1, compared with 10 of 15 (67%) read as 1/0 or greater.
  • Asbestos-related findings were markedly fewer in women. On x-ray films there was one report of pleural thickening and none of interstitial lung disease.
• The authors' conclusion: The authors concluded that x-ray readings of asbestos-related disease were generally confirmed on CT scans, and that CT scans detected three to five times more cases than x-ray films, the majority of them minor.
• Limitations the authors state:
  • X-ray films and CT scans were each read by a single physician, which raises questions especially for borderline readings.
  • No measurements of asbestos exposure were made.
  • Clinical information was not available, so interstitial lung disease in any one individual could have causes other than asbestosis.
  • The high specificities and negative predictive values of x-ray are inflated by how infrequent these findings were.

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: Lung Cancer, Interstitial Lung Disease, Pleural Thickening, CT Scan.

Related studies

• 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 and significance of chest radiograph and pulmonary function abnormalities in an elderly cohort of former nuclear weapons workers — M.A. Mikulski, P.G. Hartley, et al. (2011)
• Mortality among U.S. military participants at eight aboveground nuclear weapons test series — J.D. Boice, S.S. Cohen, et al. (2022)
• Impact of low-dose computed tomography screening on lung cancer mortality among asbestos-exposed workers — F. Barbone, F. Barbiero, et al. (2018)
• Mortality and cancer incidence of Australian participants in the British nuclear tests in Australia — R.T. Gun, J. Parsons, et al. (2008)
• Pleural plaques in lung cancer screening by low-dose computed tomography: prevalence, association with lung cancer and mortality — M. Silva, N. Sverzellati, et al. (2017)

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