Spirometry: a predictor of lung cancer among asbestos workers

Our plain-English summary of Spirometry: a predictor of lung cancer among asbestos workers, by B. Świątkowska, N. Szeszenia-Dąbrowska (Inhalation Toxicology, 2017).

The study

• Authors: B. Świątkowska, N. Szeszenia-Dąbrowska
• Journal: Inhalation Toxicology
• Published: 2017;29(1):18-22
• Read it: PubMed · Publisher

Abstract

Objective: The significance of lung function as an independent risk factor for lung cancer remains unclear. The objective of the study is to answer the question if spirometry can identify patients at risk for lung cancer among people occupationally exposed to asbestos dust in the past.

Methods: In order to identify a group of individuals with the highest risk of lung cancer incidence based on lung function levels of FEV1% predicted value, we examined 6882 subjects enrolled in the health surveillance program for asbestos related diseases over the years 2000-2014. We found a total of 110 cases confirmed as primary lung cancer.

Results: Using Cox's proportional hazards model after adjustment for age, gender, number of cigarettes, duration of smoking and cumulative asbestos exposure, we estimated that compared with the subjects with FEV1 ≥90% pred, the HR of lung cancer was 1.40 (95%CI: 0.94-2.08) for the subjects with FEV1 less than 90% and 1.95 (HR = 1.86; 95%CI: 1.12-3.08) for those with FEV1 less than 70%. In addition, probability of the occurrence of lung cancer for FEV1 <90% of the predicted value was HR = 2.19 (95%CI: 1.04-4.61) in the subjects whose time since spirometry and cancer diagnosis was three years or less.

Conclusions: The results strongly support the hypothesis that spirometry can identify patients at a risk of lung cancer development. Regular spirometry should be offered to all patients with a history of asbestos exposure, at least once every three years.

In plain English

The authors studied 6882 former workers of Polish asbestos-processing plants in the Amiantus health surveillance program who had at least one breathing test (spirometry) between 2000 and 2014. Of these, 110 developed primary lung cancer. The authors used a statistical model that took account of age, gender, smoking and cumulative asbestos exposure. With it they compared lung cancer risk by FEV1, the air forcefully blown out in the first second, as a percentage of the expected value. They compared each group with people at 90% or more. Those below 90% had a hazard ratio of 1.40 (95% CI 0.94 to 2.08). Those below 70% had 1.86 (95% CI 1.12 to 3.08). For late-stage cancer, the hazard ratio was 2.54 (1.32 to 4.89) below 90% and 3.08 (1.34 to 7.08) below 70%. Below 90%, it was 2.19 (1.04 to 4.61) when cancer was diagnosed within three years of the test. The authors concluded that spirometry can identify patients at risk of lung cancer and should be offered at least every three years. They noted that participation was voluntary and that the results cannot be generalized to general practice.

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: Analysis of participants in a health surveillance program, using Cox proportional hazards models adjusted for age, gender, cigarettes per day, smoking duration and cumulative asbestos exposure
• Who was studied: 6882 people enrolled in the Polish Amiantus health surveillance program for asbestos-related diseases who had at least one spirometry test in 2000–2014. Of these, 110 had confirmed primary lung cancer and 6772 did not.
• Exposure: Former work in asbestos processing plants in Poland. Asbestos dust exposure was expressed as a cumulative exposure index in mg/m3-years, built from 4000 workplace measurements taken from 1956 to 2000. Fiber types are not specified. The main factor studied was lung function, measured as FEV1 (forced expiratory volume in 1 second) percent of predicted value.
• Main results:
  • All participants, FEV1 below 90% of predicted compared with 90% or more: hazard ratio 1.40 (95% CI 0.94–2.08). There were 45 cancers among 1953 non-cases versus 65 among 4819.
  • All participants, FEV1 below 70% of predicted compared with 90% or more: hazard ratio 1.86 (95% CI 1.12–3.08). For FEV1 70–89%, the hazard ratio was 1.12 (95% CI 0.67–1.85).
  • Late-stage lung cancer compared with FEV1 90% or more: hazard ratio 2.54 (1.32–4.89) for FEV1 below 90%, 2.24 (1.05–4.80) for 70–89%, and 3.08 (1.34–7.08) for below 70%. Early-stage cancer, FEV1 below 70%: 2.08 (0.96–4.53).
  • The risk linked to FEV1 below 90% did not differ significantly by sex (men HR 1.51, 0.97–2.34; women HR 0.99, 0.38–2.59; p = 0.436), by smoking status (p = 0.757) or by cumulative asbestos exposure (p = 0.519).
  • Time from spirometry to diagnosis changed the result (interaction p = 0.016). For FEV1 below 90%, the hazard ratio was 2.19 (1.04–4.61) when this time was three years or less, 1.19 (0.56–2.51) for 4–6 years, and 1.15 (0.62–2.14) for 7 years or more.
• The authors' conclusion: The authors concluded that their results strongly support the hypothesis that spirometry can identify patients at risk of lung cancer. They concluded that regular spirometry should be offered to people with a history of asbestos exposure at least once every three years.
• Limitations the authors state:
  • Participation was voluntary. Participants may have been more ill, or may have wanted occupational disease status and compensation.
  • Spirometry does not give a specific diagnosis, and spirometry changes may not always reflect lung function disorders.
  • The results cannot be generalized to general practice because they concern a high-risk group of former asbestos-exposed workers.

Topics

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

Medical terms in this study, explained in our Lexicon: Spirometry, Lung Cancer, FEV1, Asbestos Exposure.

Related studies

• Effects of spirometry standards in two occupational cohorts — E.A. Eisen, L.C. Oliver, et al. (1985)
• Associations between radiographic findings and spirometry in a community exposed to Libby amphibole — T.C. Larson, M. Lewin, et al. (2012)
• Continued spirometry changes after cessation of exposure in asbestos-cement workers — B. Swiątkowska, W. Sobala, et al. (2014)
• Spirometry, rapid FEV1 decline, and lung cancer among asbestos exposed heavy smokers — J.W. Chien, D.H. Au, et al. (2007)
• Railroad workers with pleural plaques: I. Spirometric and nitrogen washout investigation on smoking and nonsmoking asbestos-exposed workers — U. Hjortsberg, P. Orbaek, et al. (1988)
• Predictors of lung cancer among former asbestos-exposed workers — B. Świątkowska, Z. Szubert, et al. (2015)

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