Digestive system cancer among persons subjected to occupational inhalation of asbestos particles: a literature review with emphasis on dose response

Our plain-English summary of Digestive system cancer among persons subjected to occupational inhalation of asbestos particles: a literature review with emphasis on dose response, by M.A. Schneiderman (Environmental Health Perspectives, 1974).

The study

• Author: M.A. Schneiderman
• Journal: Environmental Health Perspectives
• Published: 1974;9:307-11
• Cited by: 15 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 001287).

Abstract

Human data show a dose-response relationship between industrial exposure to asbestos and later development of cancer of the bronchus and lung and of cancer of the digestive tract. The data do not provide much evidence for a threshold or for the existence of a clearly "safe" level of exposure. Good dose-response data, with quantitative estimates of dose are uncommon; however, in all the literature reviewed only one paper did not support the conclusion that increased exposure to inhaled asbestos particles leads to increased digestive system cancer.

In plain English

This was a literature review by a single author at the National Cancer Institute. It examined published studies of people who breathed in asbestos at work. It compared dose-response findings for digestive system cancer with those for cancer of the bronchus and lung. The author noted there were no direct epidemiologic data on possible cancer effects of swallowed asbestos, but that some inhaled asbestos reaches the digestive tract. The main dose data came from papers by McDonald and Enterline, measured in millions of particles per cubic foot-years. The author reported the human data showed a dose-response relationship for both lung and digestive tract cancer. Only one reviewed paper did not support the idea that more inhaled asbestos leads to more digestive system cancer. For digestive cancer to occur at the same rates as lung cancer, the author estimated a factor for converting inhaled to ingested dose of 1/20 to 1/1. For both lung and gastric (stomach) cancer, the author found no strong evidence of a threshold or a clearly safe level, and noted that good dose data were uncommon.

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 focused on dose-response
• Who was studied: Published human studies of people with industrial (occupational) exposure to inhaled asbestos. The main quantitative dose-response data came from papers by McDonald (McGill University, Montreal) and Enterline (University of Pittsburgh), and other papers gave dose in semiquantitative terms.
• Exposure: Inhaled asbestos at work, with dose given in millions of particles per cubic foot-years. No fiber types are named in the available text. The author noted there were no direct epidemiologic data on the possible carcinogenic effects of ingested asbestos.
• Main results:
  • The author reported that human data showed a dose-response relationship between industrial asbestos exposure and later cancer of the bronchus and lung and cancer of the digestive tract.
  • Of all the literature reviewed, only one paper did not support the conclusion that increased exposure to inhaled asbestos particles leads to increased digestive system cancer.
  • The author estimated that the proportionality factor for converting inhaled dose to ingested dose, to produce digestive cancer at rates at the same level as bronchiogenic cancer, ranged from 1/20 to 1/1.
  • For both bronchiogenic cancer and gastric cancer, the author found that the data did not provide strong evidence for a threshold or for a clear safe level of exposure.
  • The author noted that there is evidence that some portion of inhaled asbestos eventually enters the digestive tract.
• The authors' conclusion: The author concluded that the data examined suggested an increase of digestive tract cancer associated with inhaled asbestos.
• Limitations the authors state:
  • Good dose-response data with quantitative estimates of dose were uncommon.
  • There were no direct epidemiologic data on the possible cancer-causing effects of ingested asbestos.

Topics

Medical terms in this study, explained in our Lexicon: Dose-response relationship, Bronchus.

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