The costs and effects of screening for cancer among asbestos-exposed workers

Our plain-English summary of The costs and effects of screening for cancer among asbestos-exposed workers, by B.J. McNeil, D.M. Eddy (Journal of Chronic Diseases, 1982).

The study

• Authors: B.J. McNeil, D.M. Eddy
• Journal: Journal of Chronic Diseases
• Published: 1982;35(5):351-8
• Cited by: 18 articles, as counted by NIH iCite
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 000695).

Abstract

Several million workers previously exposed to asbestos are at risk each year for developing asbestosis or cancer as a result of this exposure. We have reviewed the data on the general effectiveness of screening for the two most common cancers found in these workers (lung cancer and colo-rectal cancer) and have compared the relative benefits expected from screening workers for colon or lung cancer 10, 15, 20 or 25 yr after their initial exposure. Although lung cancer is common, there is little evidence at present that screening for this disease is effective in reducing mortality. Colon cancer is less common, there is more evidence that screening is effective, and the relatively high risk of dying from this disease in asbestos workers makes screening useful. The cost per additional year of life extended by screening is only a few hundreds of dollars, making colon cancer screening programs for asbestos workers considerably more cost-effective than most other screening programs. We conclude that occupational safety agencies should consider implementing screening programs for colon cancer in workers exposed to asbestos over 10 yr ago.

In plain English

This 1982 paper combined a review of published evidence on cancer screening with a model-based cost-effectiveness analysis for asbestos-exposed workers. The authors reviewed studies of screening for lung cancer and colon cancer, which they described as the two most common cancers in these workers. They judged that the evidence did not show that lung cancer screening reduced deaths, so they did no cost analysis for it. For colon cancer, they modeled yearly stool blood testing plus sigmoidoscopy every 5 years. The model used a hypothetical worker first exposed at age 25, with screening starting 10, 15, 20 or 25 years later. When exposed workers were assumed to have 1.56 times the usual colon cancer risk, the estimated gain in life expectancy was 141 to 166 days, at $164 to $361 per year of life gained. At 3.0 times the risk, the gains were 275 to 310 days, and screening started at age 50 saved money overall. These are model estimates, not observed outcomes. The authors concluded that screening for colon cancer offered more health benefit than screening for lung cancer in asbestos-exposed workers.

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 evidence on lung and colon cancer screening, followed by a model-based cost-effectiveness analysis of colon cancer screening only
• Who was studied: Hypothetical asbestos workers first exposed at age 25. Screening was modeled as starting 10, 15, 20 or 25 years after exposure (ages 35, 40, 45 or 50). Colon cancer incidence came from Connecticut Tumor Registry rates multiplied by the workers' relative risk.
• Exposure: Past asbestos exposure in general (no fiber type was specified for the model). After a 10-year delay, exposed workers were assumed to have 1.56 times the colon cancer risk of non-exposed people, and the analysis was repeated at 3.0. The screening modeled was a yearly occult blood test plus sigmoidoscopy every 5 years.
• Main results:
  • Lung cancer: the authors found the available screening data had not shown clear value, and they performed no cost-effectiveness analysis for lung cancer screening.
  • Colon cancer, relative risk 1.56: estimated life expectancy gain of about 166 days when screening began 10 years after exposure (age 35). Table 2 shows 141 days when screening began at age 50.
  • Colon cancer, relative risk 1.56 (Table 2): cost per year of increased life expectancy was $361 when screening began at 35, $305 at 40, $239 at 45 and $164 at 50.
  • Colon cancer, relative risk 3.0 (Table 3): life expectancy gains were 310, 304, 293 and 275 days for screening begun at ages 35, 40, 45 and 50. The cost per year of increased life expectancy was $117 at 35, $64 at 40 and $0 at 45.
  • With relative risk 3.0 and screening begun at age 50, total costs for screening and treatment were less than zero, meaning the program saved money.
  • The authors judged colon cancer screening in asbestos workers to be more cost-effective than most other screening programs they compared it with.
• The authors' conclusion: The authors concluded that more health benefit appeared to come from screening asbestos-exposed workers for colon cancer than for lung cancer. They suggested that OSHA regulations for current workers should probably include colon cancer testing. For workers who had left the exposure source, they suggested considering public programs or educating patients and physicians.
• Limitations the authors state:
  • No randomized controlled trials of lung or colon cancer screening had been completed, so the authors' benefit estimates relied on information pieced together from many sources.
  • The authors noted that the two supporting colon screening studies were uncontrolled, so patient selection or length biases complicate their interpretation.

Topics

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

Medical terms in this study, explained in our Lexicon: Lung Cancer, Colorectal Cancer.

Related studies

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• Experiences of a state-sponsored notification and screening program for asbestos workers — A.P. Bender, A.N. Williams, et al. (1993)
• Reactions of asbestos-exposed workers to notification and screening — B.E. Meyerowitz, C.D. Sullivan, et al. (1989)
• 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)
• Lung cancer risk in past asbestos workers a few decades after exposure cessation and prospects for screening — G. Mastrangelo, G. Marangi, et al. (2016)
• Can semi-automated image cytometry on induced sputum become a screening tool for lung cancer? Evaluation of quantitative semi-automated sputum cytometry on radon- and uranium-exposed workers — W. Marek, N. Kotschy-Lang, et al. (2001)

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