Asbestos-related malignancy

Our plain-English summary of Asbestos-related malignancy, by J.A. Talcott, K.H. Antman (Current Problems in Cancer, 1988).

The study

• Authors: J.A. Talcott, K.H. Antman
• Journal: Current Problems in Cancer
• Published: 1988;12(3):135-78
• Type of article: Review
• Cited by: 6 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. 000938).

Abstract

Asbestos-associated malignancies have received significant attention in the lay and medical literature because of the increasing frequency of two asbestos-associated tumors, lung carcinoma and mesothelioma; the wide distribution of asbestos; its status as a prototype environmental carcinogen; and the many recent legal compensation proceedings, for which medical testimony has been required. The understanding of asbestos-associated carcinogenesis has increased through study of animal models, human epidemiology, and, recently, the application of modern molecular biological techniques. However, the detailed mechanisms of carcinogenesis remain unknown. A wide variety of malignancies have been associated with asbestos, although the strongest evidence for a causal association is confined to lung cancer and mesothelioma. Epidemiological studies have provided evidence that both the type of asbestos fiber and the industry in which the exposure occurs may affect the rates of asbestos-associated cancers. It has been shown that asbestos exerts a carcinogenic effect independent of exposure to cigarette smoking that, for lung cancers, is synergistically enhanced by smoking. Other questions remain controversial, such as whether pulmonary fibrosis necessarily precedes asbestos-associated lung cancer and whether some threshold level of exposure to asbestos (including low-dose exposures that may occur in asbestos-associated public buildings) may be safe. Mesothelioma, the most closely asbestos-associated malignancy, has a dismal natural history and has been highly resistant to therapy. However, investigational multi-modality therapy may offer benefit to some patients. A description of the processes through which compensation claims for asbestos-associated malignancies are evaluated illustrates for physicians the legal system's approach to possible injury from toxic substances. The differences between scientific and legal reasoning about the causes of diseases with long latency, especially when they are imputed to toxic exposures are substantial, and may impede the application of toxicological evidence to legal disputes.

In plain English

This 1988 article was a review, not a new study. The authors reviewed published laboratory, epidemiologic, radiologic, clinical and legal literature on asbestos and cancer. They reported that the causal link between asbestos and other cancers is far less well established than for lung cancer and mesothelioma. They ranked crocidolite, amosite, chrysotile and possibly anthophyllite in descending order of potency. Among the studies they reviewed, one found a relative risk of lung cancer of about five in asbestos-exposed nonsmokers compared with unexposed nonsmokers. Another estimated an additional lifetime risk of lung cancer or mesothelioma of 0.8% after 35 years of exposure at 0.5 chrysotile fiber per ml. Untreated pleural mesothelioma had a median survival of 8-12 months in most series. In one series of six selected peritoneal mesothelioma patients given combined treatment, four were disease free by CT scan 3-5 years after diagnosis. The authors concluded that early, non-definitive evidence supports multimodality treatment. They also concluded that physicians and courts reason differently about causation, which slows the resolution of asbestos-related questions.

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: narrative review (monograph) of epidemiologic, laboratory, radiologic, clinical, treatment and legal literature on asbestos-related malignancy
• Who was studied: No study population of its own; the authors reviewed published studies of asbestos-exposed workers, mesothelioma patients and laboratory animals
• Exposure: Asbestos in general. The review discussed the fiber types crocidolite, amosite, chrysotile and anthophyllite, as well as occupational, household and low-dose exposures.
• Main results:
  • The authors stated that the causal relationship between asbestos and other cancers (gastrointestinal, head and neck, ovarian, breast, lymphoplasmacytic) is far less well established than for lung cancer and mesothelioma.
  • In a study the authors reviewed (by Selikoff's group), asbestos-exposed nonsmokers had a relative risk of lung cancer of approximately five compared with nonsmokers without asbestos exposure.
  • In a study the authors reviewed, Peto and colleagues used a cohort of textile factory workers to estimate that 35 years of exposure at 0.5 chrysotile fiber per ml would add a 0.8% lifetime risk of lung cancer or mesothelioma.
  • Median survival of untreated patients was 8-12 months for pleural mesothelioma in most series, and less than 12 months for peritoneal mesothelioma.
  • In a series of six carefully selected patients with peritoneal malignant mesothelioma treated with surgery, intracavitary doxorubicin and cisplatin, and abdominal radiotherapy, four were disease free by CT scan 3-5 years after diagnosis.
  • The authors stated that combination chemotherapy had no demonstrated efficacy for mesothelioma.
  • For approximately 25% of mesothelioma patients, no convincing asbestos exposure can be documented.
  • For compensation purposes, mesothelioma is presumed asbestos-caused when diagnosed more than 15 years after an asbestos exposure, even a brief one.
  • The authors judged that early, though not definitive, evidence supports multimodality treatment for mesothelioma.
• The authors' conclusion: The authors concluded that differing concepts of causation between physicians and courts mean that questions about asbestos and disease are likely to be resolved only slowly and erratically. They also concluded that innovative multimodality treatment protocols deserve further exploration.
• Limitations the authors state:
  • The authors noted that the analyses supporting multimodality therapy are not definitive because of possible confounding, including the lack of randomization.
  • The authors noted that chemotherapy data come largely from small series in poorly defined patient groups and may be subject to publication bias.
  • The authors noted that estimates of mesothelioma mortality are compromised by frequent misdiagnosis.

Topics

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

Medical terms in this study, explained in our Lexicon: Carcinoma, Mesothelioma, Carcinogenesis, Epidemiology, Lung Cancer, Carcinogenic, Pulmonary Fibrosis, Latency.

Related studies

• Asbestos-related malignancy — K.H. Antman (1986)
• Use of antisera to epithelial membrane antigen for the cytodiagnosis of malignancy in serous effusions — A. To, D.V. Coleman, et al. (1981)
• Should uncertainty concerning the risk of malignancy be included in diagnostic (nongynecologic) cytopathology reports? — D.N. Poller, F. Schmitt (2021)
• The association of asbestos and malignancy — J.G. Gillis (1965)
• Critical review of epidemiologic studies related to ingested asbestos — G.M. Marsh (1983)
• Meeting report: mode(s) of action of asbestos and related mineral fibers — M.R. Gwinn, D. DeVoney, et al. (2011)

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