Asbestos Surveillance Program Aachen (ASPA): initial results from baseline screening for lung cancer in asbestos-exposed high-risk individuals using low-dose multidetector-row CT

Our plain-English summary of Asbestos Surveillance Program Aachen (ASPA): initial results from baseline screening for lung cancer in asbestos-exposed high-risk individuals using low-dose multidetector-row CT, by M. Das, G. Mühlenbruch, A.H. Mahnken, et al (European Radiology, 2007).

The study

• Authors: M. Das, G. Mühlenbruch, A.H. Mahnken, K.G. Hering, H. Sirbu, W. Zschiesche, L. Knoll, M.K. Felten, T. Kraus, R.W. Günther, J.E. Wildberger
• Journal: European Radiology
• Published: 2007;17(5):1193-9
• Cited by: 51 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The purpose of this study was to assess the prevalence of lung cancer in a high-risk asbestos-exposed cohort using low-dose MDCT. Of a population of 5,389 former power-plant workers, 316 were characterized as individuals at highest risk for lung cancer according to a lung-cancer risk model including age, asbestos exposure and smoking habits. Of these 316, 187 (mean age: 66.6 years) individuals were included in a prospective trial. Mean asbestos exposure time was 29.65 years and 89% were smokers. Screening was performed on a 16-slice MDCT (Siemens) with low-dose technique (10/20 mAs(eff.); 1 mm/0.5 mm increment). In addition to soft copy PACS reading analysis on a workstation with a dedicated lung analysis software (LungCARE; Siemens) was performed. One strongly suspicious mass and eight cases of histologically proven lung cancer were found plus 491 additional pulmonary nodules (average volume: 40.72 ml, average diameter 4.62 mm). Asbestos-related changes (pleural plaques, fibrosis) were visible in 80 individuals. Lung cancer screening in this high-risk cohort showed a prevalence of lung cancer of 4.28% (8/187) at baseline screening with an additional large number of indeterminate pulmonary nodules. Low-dose MDCT proved to be feasible in this highly selected population.

In plain English

This German study, part of the Asbestos Surveillance Program Aachen, used low-dose CT scans to look for lung cancer in former power-plant workers who had been heavily exposed to asbestos while removing and replacing turbine insulation in a coal power plant. From 5,389 former workers, the authors selected 316 at highest risk using a score based on age, years of asbestos exposure and smoking. Of these, 187 (mean age 66.6 years, mean exposure 29.65 years, 89% smokers) were recruited between November 2002 and January 2005 and scanned. Eight had lung cancer confirmed by tissue sampling, a prevalence of 4.28% (8/187). A ninth person with a highly suspicious mass died before sampling. Five of the eight confirmed cancers were early stage. Of the nine, seven had pleural plaques and none had asbestosis. Scans showed 491 lung nodules in total, and 80 people (43%) had asbestos-related lung and/or pleural changes. No mesothelioma had been found to date. The authors concluded that the high prevalence indicated good selection of high-risk individuals. They noted that their group was relatively 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: Prospective lung cancer screening trial with low-dose multidetector-row CT; this paper reports the baseline (first-round) screening results
• Who was studied: 187 former power-plant workers in Germany (mean age 66.6 years, inclusion range 45 to 75), recruited between November 2002 and January 2005 through the Department of Occupational Health in Aachen. They came from 316 workers classed as highest risk out of 5,389 former workers. 89% were smokers, 10% ex-smokers and 1% non-smokers.
• Exposure: Heavy occupational asbestos exposure during renovation of turbines in a conventional coal power plant, which involved removing asbestos insulation and re-insulating the turbines. Mean exposure time was 29.65 years (range 16 to 45 years). Fiber type was not specified.
• Main results:
  • Among the 187 screened workers, 8 had histologically proven lung cancer, a baseline prevalence of 4.28% (8/187).
  • Nine of the 187 were considered positive for lung cancer, all of them smokers. One of the nine died before a tissue sample could be taken. Counting that case, the prevalence would be 4.8% (9/187).
  • Of the nine people considered positive for lung cancer, seven also had pleural plaques and none had asbestosis.
  • Five of the eight proven lung cancers (62.5%) were detected at an early stage; the other three were advanced, as was the mass without histology.
  • Of seven CT-guided biopsies of nodules larger than 10 mm, six showed lung cancer and one showed aspergilloma (a fungal growth) instead of cancer.
  • A total of 491 pulmonary nodules were found across all 187 individuals; 24 individuals had no nodules.
  • 80 of the 187 individuals (43%) had asbestos-related changes in the lung and/or the pleura.
  • No mesothelioma had been found in the screened population to date. One pleural biopsy done for suspicious thickening showed only benign changes.
  • The low-dose scan protocol gave an average effective radiation dose of 1.1 mSv (SD 0.4 mSv).
• The authors' conclusion: The authors concluded that the high lung cancer prevalence indicated a good selection of high-risk individuals for screening. They also concluded that low-dose screening might reduce the number of patients with advanced lung cancer and might be beneficial in this selected population.
• Limitations the authors state:
  • The study population was relatively small compared with some other screening studies.
  • The very thin-slice protocol found a very high number of small non-calcified nodules. It is not yet known whether all of these need follow-up.
  • The authors suggested that finding no mesothelioma might be due to the small study population.

Topics

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

Medical terms in this study, explained in our Lexicon: Lung Cancer, Asbestos Exposure, Habit, Pleural Plaques, Fibrosis, Low-Dose CT Screening.

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)
• Low-dose computed tomography screening for lung cancer and pleural mesothelioma in an asbestos-exposed population: baseline results of a prospective, nonrandomized feasibility trial--an Alpe-adria Thoracic Oncology Multidisciplinary Group Study (ATOM 002) — G. Fasola, O. Belvedere, et al. (2007)
• CT scan screening for lung cancer: risk factors for nodules and malignancy in a high-risk urban cohort — A.K. Greenberg, F. Lu, et al. (2012)
• Low-dose chest computed tomography screening of subjects exposed to asbestos — K. Kato, K. Gemba, et al. (2018)
• Occupational carcinogenesis. High-risk industrial groups: identification, education, and surveillance. Tyler Asbestos Workers Program — S.D. Greenberg, G.A. Hurst, et al. (1976)
• Non-response bias in a surveillance program for asbestos-related lung cancer — L. Knoll, M.K. Felten, et al. (2011)

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