Occupational exposures in rare cancers: A critical review of the literature

Our plain-English summary of Occupational exposures in rare cancers: A critical review of the literature, by B. Charbotel, B. Fervers, J.P. Droz (Critical Reviews in Oncology/hematology, 2014).

The study

• Authors: B. Charbotel, B. Fervers, J.P. Droz
• Journal: Critical Reviews in Oncology/hematology
• Published: 2014;90(2):99-134
• Type of article: Review
• Cited by: 39 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The contribution of occupational exposures to rare cancers, which represent 22% of all cancers diagnosed annually in Europe, remains insufficiently considered. We conducted a comprehensive review of occupational risk factors in 67 rare cancers (annual incidence <6/100,000). An examination of relevant articles in PubMed (1960-2012) and the International Agency for Research on Cancer (IARC) monographs revealed that 26 cancer sites, such as mesothelioma, nasal, larynx, liver, ovarian cancer, bone sarcoma, and hematopoietic malignancies were consistently linked to occupational factors. Main exposures included asbestos, wood dust, metals/metalloids, formaldehyde, benzene, vinyl chloride, and radiation. There was inconsistent evidence regarding 22 rare malignancies. We did not identify relevant data for 19 rare cancers. Despite limitations of published evidence, our review provides useful information that can facilitate the identification of work-related factors that contribute to rare cancers. International collaborations, development of improved exposure assessment methods, and molecular approaches can improve future studies.

Copyright © 2014 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

In plain English

This article was a review of published research, not a new study. The authors searched PubMed from 1960 to December 2012, and the IARC monographs, for cohort studies, case–control studies and meta-analyses linking work exposures to 67 rare cancers. Rare cancers were those with fewer than 6 cases per 100,000 per year, and the search found 6820 articles. For 26 cancers, including mesothelioma and cancers of the nose, larynx, liver and ovary, the evidence consistently linked them to occupational factors. For 22 cancers the evidence was inconsistent or insufficient, and for 19 the authors found no relevant occupational exposure studies. The asbestos studies the review tabulated included a cohort of 98,912 asbestos workers (649 mesothelioma cases). That cohort had a mesothelioma SMR of 13.3 (95% confidence interval 12.3 to 14.4) in men and 30.9 (18.3 to 48.8) in women. The tabulated studies also included meta-analyses of laryngeal and ovarian cancer. The authors concluded that the main exposures included asbestos, wood dust, metals and metalloids, formaldehyde, benzene, vinyl chloride and radiation. They noted that they did not cross-search the exposures identified, and that the rarity of these cancers limits study power.

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: Literature review of epidemiological studies (cohort and case–control studies, meta-analyses) and IARC monographs
• Who was studied: Published research on 67 rare cancers (annual incidence below 6 per 100,000, per RARECARE), found through PubMed searches from 1960 to December 2012 (6820 articles identified) and IARC monographs
• Exposure: A wide range of occupational exposures; the main ones identified were asbestos, wood dust, metals/metalloids, formaldehyde, benzene, vinyl chloride and radiation
• Main results:
  • 26 rare cancer sites, including mesothelioma, were consistently linked to occupational factors
  • For 22 rare malignancies the evidence was inconsistent or insufficient, and for 19 cancers no relevant occupational exposure studies were identified
  • Tabulated study (Harding et al.) of 98,912 asbestos workers with 649 mesothelioma cases: SMR 13.3 (12.3–14.4) in men and 30.9 (18.3–48.8) in women
  • Mesothelioma risk appeared higher for amphibole fibers; a tabulated meta-analysis (Berman et al.) gave an amphibole SMR of 13.8 (3.5–26.3)
  • Laryngeal cancer and asbestos: a tabulated meta-analysis of 69 asbestos-exposed occupational cohorts (Goodman et al.) gave a meta-SMR of 133 (114–155)
  • Ovarian cancer and asbestos: a tabulated meta-analysis of 18 studies (Camargo et al.) gave an SMR of 1.77 (1.37–2.28)
  • Hypopharyngeal cancer and asbestos: a tabulated hospital-based case–control study (Marchand et al.) found OR 2.14 (1.14–4.01) at the highest exposure level
  • Small intestine cancer: a tabulated cohort of 2024 asbestos-exposed subjects (3 cases) found SIR 6.93 (1.39–20.25) among men with exposure above 80 fibers/mL × years; the review classed the evidence for this cancer as insufficient
• The authors' conclusion: The authors concluded that the rare cancer sites with strong and consistent evidence were nasal, larynx, liver and ovarian cancer, mesothelioma, bone sarcoma, transitional cell carcinoma of non-bladder urinary organs and hematopoietic malignancies
• Limitations the authors state:
  • The authors did not cross-search for the exposures they identified, so studies with negative results for a given cancer site may have been missed
  • Because rare cancers are uncommon, adequately powered studies are hard to conduct
  • Many studies were excluded because they lacked subtype-specific histology details

Topics

Medical terms in this study, explained in our Lexicon: Occupational Exposure, IARC, Mesothelioma, Ovarian Cancer, Sarcoma.

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