Association Between Laryngeal Cancer and Asbestos Exposure: A Systematic Review

Our plain-English summary of Association Between Laryngeal Cancer and Asbestos Exposure: A Systematic Review, by A.P.O. Ferster, J. Schubart, Y. Kim, et al (JAMA Otolaryngology-- Head & Neck Surgery, 2017).

The study

• Authors: A.P.O. Ferster, J. Schubart, Y. Kim, D. Goldenberg
• Journal: JAMA Otolaryngology-- Head & Neck Surgery
• Published: 2017;143(4):409-416
• Type of article: Systematic review
• Cited by: 19 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Importance: It has been debated whether a link exists between laryngeal cancer and asbestos exposure. Prior systematic reviews have been conducted on this topic, but no updates have been performed on the most recent literature since 2000.

Objective: To provide an updated systematic review of the association between laryngeal cancer and asbestos exposure.

Evidence Acquisition: A search of electronic databases, including PubMed and the Cochrane Library, was performed for articles published between January 1, 2000, and April 30, 2016. Search terms, including laryngeal cancer and asbestos, were used to identify publications reviewing the risk of laryngeal cancer in association with asbestos exposure. Studies analyzing this association that were published in any language and translated reliably were included. Two independent reviewers assessed articles based on predetermined eligibility criteria. Each study was reviewed for quality using the Oxford Centre for Evidence-Based Medicine 2011 Levels of Evidence and assessed for their findings of support for or against a correlation between asbestos exposure and laryngeal cancer.

Findings: A total of 160 studies were retrieved from all databases, and 2 additional articles were identified by cross-references. Of the 162 articles screened, 15 articles comprising 438 376 study participants were included in this review. Of these 15 studies, 10 showed no correlation between asbestos exposure and laryngeal cancer. The remaining 5 studies claimed a correlation between asbestos exposure and incidence of laryngeal cancer, although only 1 accounted for smoking or alcohol exposure while 3 others did not, and 1 study included only 2 patients.

Conclusions And Relevance: Although asbestos is considered hazardous and carcinogenic, current evidence is lacking to support a correlation between asbestos exposure and laryngeal cancer. Few studies have been able to definitively conclude a causal association between asbestos exposure and laryngeal cancer, and those that found an association often did not account for the confounding factors of tobacco and alcohol exposure.

In plain English

This article was a systematic review of earlier research. The authors searched PubMed and the Cochrane Library for studies on asbestos exposure and laryngeal cancer (cancer of the voice box) published from January 1, 2000, to April 30, 2016, updating a review from 2000. Of 162 articles screened, 15 primary studies with 438 376 participants were included: 5 case-control studies and 10 cohort studies. Most participants were men, and most studies came from European countries. The authors reported that 10 of the 15 studies showed no correlation between asbestos exposure and laryngeal cancer. By the authors' count, of the 5 studies claiming a correlation, 1 accounted for smoking or alcohol, 3 did not, and 1 had only 2 laryngeal cancer patients among 307 799 Swedish construction workers. The authors concluded that current evidence is lacking to support a correlation and that a causal link has not been established definitively. They noted that many included studies did not account for smoking and alcohol and were open to recall bias. The article's table and text disagree in several places.

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: Systematic review (an update of a 2000 review) of PubMed and Cochrane Library literature published January 1, 2000, to April 30, 2016; no pooled meta-analysis was performed
• Who was studied: 15 primary studies (5 case-control, 10 cohort) with 438 376 participants in total, selected from 162 screened articles; mostly men and mostly European countries (also the United States, Canada and Australia)
• Exposure: Asbestos exposure, mainly occupational. Included studies covered groups such as piping and plumbing workers, asbestos-cement workers, asbestos workers, chrysotile asbestos miners, navy servicemen and construction workers. The review did not analyze results by fiber type.
• Main results:
  • Of the 15 included studies, 10 showed no correlation between asbestos exposure and laryngeal cancer; the remaining 5 claimed a correlation
  • By the authors' tally, of the 5 studies claiming a correlation, 1 accounted for smoking or alcohol exposure and 3 did not. The fifth study had only 2 patients with laryngeal cancer; per the table, this was the Purdue et al study of 307 799 Swedish construction workers.
  • Among the case-control studies, 3 accounted for smoking and alcohol. Their odds ratios ranged from 0.86 (95% CI, 0.51-1.45) to 1.0 (95% CI, 0.8-1.3), and 2 of these 3 found no correlation.
  • Menvielle et al (2780 controls, 473 patients; French males) reported an odds ratio of 1.81 (95% CI, 1.32-2.48) for the highest level of asbestos exposure. According to the review, that study reported no calculation that excluded alcohol or smoking exposure.
  • Purdue et al studied 307 799 Swedish construction workers and reported a relative risk of 1.8 (95% CI, 0.8-4.3). Only 2 of the workers were patients with laryngeal cancer. The review described that study as accounting for smoking but not alcohol.
  • Offermans et al (58 279 Netherlands males) reported a hazard ratio of 6.36 (95% CI, 2.18-18.53). The review lists this study as accounting for smoking and alcohol but describes it as not finding a correlation.
  • The remaining 8 cohort studies did not account for smoking and alcohol; 2 of them reported an increased risk of laryngeal cancer with asbestos exposure
• The authors' conclusion: The authors concluded that current evidence is lacking to support a correlation between asbestos exposure and laryngeal cancer. They added that a causal link has not been established definitively and that studies accounting for confounding exposures are needed.
• Limitations the authors state:
  • Studies that found an association often did not account for tobacco and alcohol as confounding factors
  • Participants may have had several other industrial exposures, which could act as confounders
  • Many of the studies had small numbers of laryngeal cancer cases
  • All included studies were at risk of recall bias about asbestos, other industrial exposures, alcohol or tobacco
  • Sex and region could be confounders, because most patients were men and most countries were European

Topics

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

Medical terms in this study, explained in our Lexicon: Laryngeal Cancer, Asbestos Exposure, Systematic Review, Carcinogenic, Confounding.

Related studies

• Exposure to nitrosamines, carbon black, asbestos, and talc and mortality from stomach, lung, and laryngeal cancer in a cohort of rubber workers — K. Straif, U. Keil, et al. (2000)
• Occupational risk factors for laryngeal carcinoma: Connecticut, 1975-1980 — R.T. Zagraniski, J.L. Kelsey, et al. (1986)
• Laryngeal cancer: an explanation for the apparent occupational association — A. Chovil (1981)
• Asbestos and laryngeal carcinoma — P.M. Stell, T. McGill (1973)
• Epidemiological evidence indicates asbestos causes laryngeal cancer — A.H. Smith, M.A. Handley, et al. (1990)
• Exposure to asbestos and laryngeal carcinoma — P.M. Stell, T. McGill (1975)

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