Setting new standards for epidemiological research on mesothelioma

Our plain-English summary of Setting new standards for epidemiological research on mesothelioma, by P. Boffetta, C. La Vecchia (Occupational and Environmental Medicine, 2016).

The study

• Authors: P. Boffetta, C. La Vecchia
• Journal: Occupational and Environmental Medicine
• Published: 2016;73(5):289
• Type of article: Comment
• Cited by: 7 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Summary of the article

In this commissioned commentary, the authors discussed a study by Gilham et al, published in the same journal. That study was the first to use lung fibre burden to estimate past asbestos exposure in a large British population-based study of pleural mesothelioma. The commentators noted possible sources of bias. Lung samples were analysed for 134 cases, 21.5% of the original case-control study. Controls were resected lung cancer cases, who represent less advanced disease and would be expected to have higher fibre burdens than the general population. Sample retrieval among controls was 262/420 (62.4%). They wrote that a quantitative assessment of selection bias would have been helpful. In their view, the study confirmed the predominant role of amphibole exposure. They noted that lung burden studies cannot adequately estimate the effect of chrysotile because of its short biopersistence. They considered the most important result to be the linear dose-response between amphibole lung burden and mesothelioma risk, as predicted by the 1982 model of Peto et al. They also highlighted the first fibre-burden-based estimate of the relative effect of crocidolite versus amosite. Many cases in low-risk occupations had relatively high fibre burdens. The authors suggested that job-based assessment would miss occupation-related cases and that fibre burden analysis could help identify cases deserving compensation. Alternatively, environmental exposures may have contributed. They concluded that the study set a new standard and stressed the value of collecting tissue samples. Both authors declared that they had acted as expert witnesses in asbestos-related litigation.

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 commentary, not an original study, discussed a study by Gilham and colleagues. That study used lung fibre levels to estimate past asbestos exposure in pleural mesothelioma patients in Great Britain, with resected lung cancer controls. According to the commentators, it analysed samples from 134 cases, 21.5% of the mesothelioma cases in an earlier case–control study. It found a linear dose–response between lung amphibole fibre burden and mesothelioma risk, and gave a first lung-burden estimate of crocidolite's effect relative to amosite. It also found a substantial number of cases in low-risk occupations with relatively high fibre burden. The commentators noted possible bias: control samples were retrieved for only 262 of 420 people (62.4%). Resected lung cancer patients have less advanced disease and would be expected to carry more fibre than the general population. Fibre burden studies are inadequate to estimate chrysotile's effect because chrysotile does not persist long in the lung. The commentators suggested that judging exposure by job titles would miss many cases. They concluded the Gilham study sets a new standard and stresses collecting tissue samples.

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: Commentary (commissioned, internally peer reviewed) on another published study (Gilham et al, Occup Environ Med 2015); no new data
• Who was studied: No population of its own. The discussed study (Gilham et al) analysed lung samples from 134 pleural mesothelioma cases, which were 21.5% of the cases included in an earlier British case–control study. It used resected lung cancer cases as controls (samples retrieved for 262 of 420).
• Exposure: Asbestos lung fibre burden, mainly amphiboles (crocidolite and amosite). The commentators said fibre burden studies are inadequate for chrysotile.
• Main results:
  • As described by the commentators, Gilham et al found a linear dose–response between lung fibre (amphibole) burden and mesothelioma risk
  • As described by the commentators, the Gilham study confirmed the predominant role of amphibole exposure in causing mesothelioma
  • As described by the commentators, the Gilham study gave the first estimate, based on lung fibre burden, of the relative effect of crocidolite versus amosite. The commentary gives no figures for this estimate.
  • As described by the commentators, a substantial number of mesothelioma cases occurred in people employed in low-risk occupations who had relatively high lung fibre burden
  • The commentators' interpretation: exposure assessment based on job and industry titles would miss a sizable proportion of occupation-related cases. Alternatively, environmental exposures may have contributed to fibre burden.
• The authors' conclusion: The authors concluded that the Gilham study sets a new standard for epidemiological research on asbestos and mesothelioma, and that it stresses the importance of collecting tissue samples in cancer epidemiology studies
• Limitations the authors state:
  • Limitation of the Gilham study, as stated by the commentators: the lung fibre burden method is open to bias because unbiased groups of case and control lung samples are hard to obtain
  • Limitation of the Gilham study, as stated by the commentators: resected lung cancer controls have less advanced disease. Because asbestos is linked to lung cancer, they would also be expected to have higher fibre burdens than the population at large.
  • Limitation of the Gilham study, as stated by the commentators: the sample retrieval rate among controls was suboptimal (262/420, or 62.4%)
  • Limitation of the Gilham study, as stated by the commentators: no quantitative assessment of the possible impact of selection bias was made
  • Limitation stated by the commentators: lung fibre burden studies are inadequate to estimate the effect of chrysotile because of its short biopersistence. This concerns the exposure measure, not whether chrysotile has an effect.
  • Limitation stated by the commentators: predictions of future mesothelioma rates from fibre burden in young people should be treated with caution

Topics

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

Medical terms in this study, explained in our Lexicon: Mesothelioma, Asbestos Exposure, Pleural Mesothelioma, Case-Control Study, Lung Cancer, Selection Bias, Amphibole Group, Chrysotile.

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