Association of asbestos exposure with colorectal adenomatous polyps and cancer

Our plain-English summary of Association of asbestos exposure with colorectal adenomatous polyps and cancer, by A.I. Neugut, T.I. Murray, G.C. Garbowski, et al (Journal of the National Cancer Institute, 1991).

The study

• Authors: A.I. Neugut, T.I. Murray, G.C. Garbowski, M.R. Treat, K.A. Forde, J.D. Waye, C. Fenoglio-Preiser
• Journal: Journal of the National Cancer Institute
• Published: 1991;83(24):1827-8
• Cited by: 11 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. 004919).

Summary of the article

This brief communication examined whether asbestos exposure was associated with colorectal adenomatous polyps, which are generally accepted as precursors of most colorectal cancers, as well as with colorectal cancer. The authors carried out a case-control study of patients aged 35-84 years who underwent colonoscopy in three practices at two major medical centers in New York City between April 1986 and March 1988. Of 2879 patients, 2334 were eligible and 1892 were interviewed by telephone or mail. Because almost no women reported asbestos exposure, the analysis was limited to men: 51 colorectal cancer cases, 153 adenomatous polyp cases, and 195 controls free of colorectal neoplasia. Men were asked whether they had ever been exposed to asbestos. Two occupational medicine physicians, blinded to case or control status, then reviewed the answers to identify significant exposure. Odds ratios were adjusted for age using logistic regression. Of the 56 men who reported any exposure, 12 were judged to have potentially significant exposure. Any reported exposure was not associated with significantly raised risk. For significant exposure, the odds ratio was 4.3 (95% CI 0.8-23.5) for cancer and 3.6 (95% CI 0.8-15.7) for adenomatous polyps. The authors described these elevations as borderline and their findings as preliminary, citing small numbers and wide confidence intervals. They suggested an endoscopic screening study of an asbestos-exposed occupational cohort.

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 brief report described a case-control study of men aged 35 to 84 who had a colonoscopy at three practices at two medical centers in New York City between April 1986 and March 1988. It compared 51 men with colorectal cancer and 153 men with adenomatous polyps (growths generally accepted as precursors of most colorectal cancers) with 195 men free of such growths. Each man was asked whether he had ever been exposed to asbestos, and 56 said yes. Two occupational medicine physicians, who did not know which men were cases, judged 12 of them to have potentially significant exposure. Their jobs included work with asbestos pipes, pipes and boilers, and shipbuilding. Reporting any asbestos exposure was not linked to a significantly raised risk. For significant exposure, the age-adjusted odds ratio was 4.3 (95% confidence interval 0.8 to 23.5) for cancer and 3.6 (0.8 to 15.7) for polyps. The authors called these borderline significant. The authors concluded that significant exposure was associated with elevated risk of polyps and of colorectal cancer. They regarded the findings as preliminary because of small numbers and very wide confidence intervals.

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: Case-control study (brief communication), with multiple logistic regression adjusted for age
• Who was studied: Patients aged 35-84 who underwent colonoscopy in three practices at two major medical centers in New York City, April 1986 to March 1988. Of 2879 patients (men and women), 2334 were eligible and 1892 were interviewed by telephone or mail. Analysis was limited to men, because almost none of the women reported asbestos exposure. The final groups were 51 colorectal cancer cases, 153 adenomatous polyp cases and 195 controls free of colorectal neoplasia. The three groups were comparable in educational attainment.
• Exposure: Self-reported asbestos exposure ('ever exposed', yes or no). Two occupational medicine physicians, blinded to case or control status, reviewed the men's descriptions of their exposure and classified 'significant' exposure. Jobs of the 12 men with significant exposure included plant mechanic with pipes and boilers, water engineer working with asbestos pipes, shipbuilding, school custodian, and inspecting asbestos fireproofing. Fiber types were not named.
• Main results:
  • Any self-reported asbestos exposure was not associated with a significant elevation in risk in either case group. Cancer cases: 10/51 (19.6%), age-adjusted odds ratio 1.8 (95% CI 0.8-5.6). Polyp cases: 20/153 (13.1%), odds ratio 1.1 (95% CI 0.6-2.1). Controls: 26/195 (13.3%).
  • Of the 56 men who reported any asbestos exposure, the blinded review identified 12 with potentially significant exposure.
  • Significant exposure among colorectal cancer cases: 3/51 (5.9%), compared with 3/195 (1.5%) of controls. The age-adjusted odds ratio was 4.3 (95% CI 0.8-23.5).
  • Significant exposure among adenomatous polyp cases: 6/153 (3.9%), compared with 3/195 (1.5%) of controls. The age-adjusted odds ratio was 3.6 (95% CI 0.8-15.7).
  • The authors described the age-adjusted odds ratios for significant exposure as borderline significantly elevated for both case groups, significant only at the 0.05 to 0.10 levels.
• The authors' conclusion: The authors concluded that the study found an elevated risk for adenomatous polyps among men with significant asbestos exposure, and a similar elevated risk for colorectal cancer. They suggested that an endoscopic screening study of an asbestos-exposed occupational cohort would provide data on these hypotheses.
• Limitations the authors state:
  • The authors stated that the findings must be regarded as preliminary.
  • Sample sizes were relatively small and few cases were exposed, giving very wide confidence intervals; the authors said the point estimates of risk must be regarded as soft.
  • The authors considered recall bias but believed it was minimal, because similar proportions of cases and controls reported any asbestos exposure.

Topics

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

Medical terms in this study, explained in our Lexicon: Asbestos Exposure, Colorectal Cancer, Case-Control Study, Odds Ratio, confidence interval.

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