Epidemiology of gastrointestinal cancer

Our plain-English summary of Epidemiology of gastrointestinal cancer, by I.J. Selikoff (Environmental Health Perspectives, 1974).

The study

• Author: I.J. Selikoff
• Journal: Environmental Health Perspectives
• Published: 1974;9:299-305
• Cited by: 25 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. 001288).

Abstract

Some 99,000 new cases of cancer of the colon are expected next year, an incidence rate higher than that for both cancer of the lung and cancer of the breast. Evidence from geographic pathology suggests that some environmental factors play a strong role in its etiology. Data obtained in the 1959 survey of one million people by the American Cancer Society and followed since, has failed to show correlation with any of the large number of factors listed. It is suggested that the etiology is one of multiple factors. The synergistic effect of exposure to asbestos and cigarette smoking in the production of bronchogenic carcinoma is demonstrated by data on cohorts of insulation workers. There was also a modest increase in the number of deaths from gastrointestinal cancer in asbestos workers, but smoking did not seem to act in synergistic fashion at that site, except perhaps in the esophagus. Deaths from cancer occurred almost entirely after a period of 20 years or more from initial exposure. The death rate from cancer tended to increase with duration of exposure, but a distinct rise over the expected was seen in those who had been exposed less than one year to amosite dust.

In plain English

This article first reviewed earlier research on the causes of colon cancer. It then presented mortality data from the authors' studies of asbestos workers. Among 632 New York-area insulation workers followed from 1943 to 1962, there were 255 deaths where about 203 were expected. These included 45 intrathoracic cancers against 6.6 expected, and 29 gastrointestinal cancers against 9 or 10 expected. Among 370 survivors followed to 1971, the 87 non-cigarette-smokers had one bronchogenic carcinoma death. The 283 cigarette smokers had 41 against 3.3 expected. Among 17,800 union insulation workers in the United States and Canada, followed from 1967 to 1971, colon and rectal cancer showed a modest increase that was not associated with smoking. Esophageal cancer was increased. Cancer deaths occurred almost all more than 20 years after first exposure. At an amosite factory, lung cancer was increased even among men who worked there less than 3 months. On colon cancer, the authors concluded that they leaned toward multiple factors acting together. They noted that small numbers limited some findings.

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: Overview article: a review of colon cancer epidemiology, followed by mortality data from the authors' own cohort studies of asbestos workers (some previously published)
• Who was studied: Three groups: 632 asbestos insulation union members in the New York metropolitan area as of January 1, 1943 (370 survivors examined in 1963); 17,800 insulation union members in the United States and Canada as of January 1, 1967; and 933 men employed 1941-1945 at an amosite asbestos products factory (876 analysed)
• Exposure: Asbestos exposure in insulation work and in an amosite asbestos products factory, studied together with cigarette smoking history
• Main results:
  • In the 632 insulation workers, 1943-1962, there were 255 deaths against about 203 expected.
  • In the same 632 workers there were 45 intrathoracic cancer deaths against 6.6 expected.
  • In the same 632 workers there were 29 gastrointestinal cancer deaths against 9 or 10 expected, which the author called a modest increase.
  • Among the 87 survivors with no history of cigarette smoking, followed to December 31, 1971, there was one bronchogenic carcinoma death, in a pipe smoker.
  • Among the 283 survivors with a cigarette smoking history, there were 41 bronchogenic carcinomas against 3.3 expected.
  • Among the 17,800 workers, 1967-1971, the 2,066 men with no cigarette smoking history had two lung cancer deaths.
  • Among the 9,590 men with a cigarette smoking history, there were 134 bronchogenic carcinoma deaths, about five times the expected number.
  • In the 17,800 workers, cancer of the colon and rectum showed a modest increase (26 observed against 17.51 expected overall), and this increase was not associated with smoking.
  • Cancer of the esophagus was increased in the 17,800 workers: 13 deaths against 3.21 expected overall; 0 against 0.44 among men with no cigarette smoking history; 7 against 1.80 among cigarette smokers; 6 against 0.97 among men whose smoking history was not known.
  • Cancer deaths, including from colon and rectal cancer, occurred almost all more than 20 years after onset of exposure.
  • Among the amosite factory workers followed to the end of 1971, 73 lung cancers occurred where 11 were expected (Table 8: 73 observed against 11.22 expected in 876 men).
  • At the amosite factory, lung cancer risk was significantly increased even with less than 1 year, and less than 3 months, of employment. Table 8: under 3 months, 13 observed against 3.55 expected; 3-11 months, 15 against 3.58; 1 year or more, 45 against 4.09.
• The authors' conclusion: On colon cancer, the author and Hammond leaned toward the view that critical combinations of multiple factors are responsible, rather than any single factor.
• Limitations the authors state:
  • The gastrointestinal cancer excess in the first cohort was not conclusive because of small numbers and because it came from only one cohort.
  • The 370-man group included only 87 nonsmokers, too few for strong statements.
  • The authors' experience was too limited to say whether lymphomas and leukemias are increased in asbestos workers.

Topics

Medical terms in this study, explained in our Lexicon: Epidemiology, Incidence, Pathology, Etiology, Synergistic Effect, Bronchogenic Carcinoma, Insulator, Amosite.

Related studies

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• Aerodigestive and gastrointestinal tract cancers and exposure to crocidolite (blue asbestos): incidence and mortality among former crocidolite workers — A. Reid, G. Ambrosini, et al. (2004)
• Cancer of the gastrointestinal tract and exposure to asbestos in drinking water among lighthouse keepers (Norway) — K. Kjaerheim, B. Ulvestad, et al. (2005)
• Asbestos ingestion and gastrointestinal cancer: a possible underestimated hazard — A. Di Ciaula (2017)
• Gastrointestinal carcinoma and occurrence of pleural plaques on pulmonary X-ray — G. Hillerdal (1980)
• Assessing Tumor-Infiltrating Lymphocytes in Solid Tumors: A Practical Review for Pathologists and Proposal for a Standardized Method from the International Immuno-Oncology Biomarkers Working Group: Part 2: TILs in Melanoma, Gastrointestinal Tract Carcinomas, Non-Small Cell Lung Carcinoma and Mesothelioma, Endometrial and Ovarian Carcinomas, Squamous Cell Carcinoma of the Head and Neck, Genitourinary Carcinomas, and Primary Brain Tumors — S. Hendry, R. Salgado, et al. (2017)

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