Asbestos exposure and neoplasia

Our plain-English summary of Asbestos exposure and neoplasia, by I.J. Selikoff, J. Churg, E.C. Hammond (JAMA, 1964).

The study

• Authors: I.J. Selikoff, J. Churg, E.C. Hammond
• Journal: JAMA
• Published: 1964;188:22-6
• Cited by: 544 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. 001557).

Abstract

Building trades insulation workers have relatively light, intermittent, exposure to asbestos. Of 632 insulation workers, who entered the trade before 1943 and were traced through 1962, forty-five died of cancer of the lung or pleura, whereas only 6.6 such deaths were expected. Three of the pleural tumors were mesotheliomas; there was also one peritoneal mesothelioma. Four mesotheliomas in a total of 255 deaths is an exceedingly high incidence for such a rare tumor. In addition, an unexpectedly large number of men died of cancer of the stomach, colon, or rectum (29 compared with 9.4 expected). Other cancers were not increased; 20.5 were expected, 21 occurred. Twelve men died of asbestosis.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.

In plain English

This study followed 632 men who were members of two asbestos insulation workers' union locals, in New York and in Newark, New Jersey, as of 1942. It traced their deaths from January 1, 1943, through December 31, 1962. A man's experience was counted only once 20 years had passed since his first exposure to asbestos. Observed deaths were compared with the numbers expected from death rates for all US white males. Of the 632 men, 255 died. Forty-five died of cancer of the lung or pleura, compared with 6.6 expected. Three pleural tumors were recorded as mesotheliomas, and there was one peritoneal mesothelioma. Twelve men died of stomach cancer (4.3 expected) and 17 of colon or rectal cancer (5.2 expected). Cancers of all other sites were not increased: 21 deaths against 20.5 expected. Twelve men died of asbestosis. The authors argued that smoking could not explain the lung cancer excess, but they had not learned the smoking habits of the men who died. They concluded that lung cancer was about six to seven times the expected level. They cautioned that their results might not apply to other asbestos industries.

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: Cohort mortality study, which the authors call a prospective epidemiological study, of union members. Observed deaths were compared with deaths expected from the death rates of all US white males, taking age and calendar period into account.
• Who was studied: 632 men on the 1942 rolls of New York Local 12 and Newark, NJ, Local 32 of the International Association of Heat and Frost Insulators and Asbestos Workers. Their deaths were followed from January 1, 1943, through December 31, 1962. The study covered 8,737.5 man-years, counted only after each man reached 20 years since first exposure.
• Exposure: Asbestos exposure in building-trades insulation work; no fiber type is named. The authors describe the exposure as intermittent, to materials containing limited amounts (often 2% to 20%) of asbestos. Working conditions ranged from very dusty, such as removing old insulation in closed spaces, to little dust, such as open-air building construction.
• Main results:
  • Of the 632 men, 255 died during the 1943 to 1962 follow-up.
  • 45 of the 632 men died of cancer of the lung or pleura, compared with 6.6 deaths expected from US white male rates. Of these 45, 42 were recorded as bronchogenic carcinoma and 3 as pleural neoplasms, all recorded as mesotheliomas. The death rate from these cancers was 6.8 times that of the general US white male population.
  • There were four mesotheliomas among the 255 deaths: three pleural and one peritoneal. The authors described this as an exceedingly high incidence for such a rare tumor.
  • Among the asbestos workers there were 12 deaths from stomach (gastric) cancer, compared with 4.3 expected. There were 17 deaths from cancer of the colon and rectum, compared with 5.2 expected.
  • Deaths from cancers of all other sites combined were not increased: 21 among the asbestos workers, compared with 20.5 expected.
  • 12 of the 255 deaths were due to asbestosis. Time from first asbestos exposure to death from asbestosis averaged 45.8 years, with a range of 32 to 59 years.
  • Deaths from all causes were below expected in 1943 to 1947 (28 observed, 39.7 expected). They were above expected in later periods, for example 88 observed and 54.4 expected in 1958 to 1962. The authors attributed the early low rate to the men being selected as actively employed, not disabled, workers at the start.
  • The authors interviewed 320 of the 377 surviving members about smoking and found that a substantial proportion had never smoked cigarettes regularly. They estimated that even if all the men had smoked a pack or more a day, and asbestos had no effect, their lung cancer death rate would have been about 3.4 times the general rate, compared with the 6.8 times observed.
• The authors' conclusion: The authors concluded that industrial asbestos exposure among insulation workers, as studied here, resulted in a marked increase in lung cancer, about six to seven times the expected incidence. They concluded that smoking habits could not account for this. They wrote that the data suggest there may perhaps be a causal relationship between industrial asbestos exposure and cancer of the gastrointestinal tract.
• Limitations the authors state:
  • The results relate to the specific conditions of this trade and period. They would not necessarily apply to other industries, such as factory production of asbestos products or asbestos textiles, where conditions may differ.
  • The authors had not yet determined the smoking habits of the men who died. Their smoking sample, taken from surviving members only, was somewhat inadequate.
  • Counting diffuse pleural mesothelioma is complicated because its diagnosis under the microscope is uncertain. Other tumors can mimic it.

Topics

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

Medical terms in this study, explained in our Lexicon: Asbestos Exposure, Insulator, Pleura, Mesothelioma, Peritoneal Mesothelioma, Stomach Cancer.

Related studies

• American Cancer Society plans for a long-range study of colonic and rectal cancer — E.C. Hammond (1970)
• A meta-analysis of colorectal cancer and asbestos exposure — D.M. Homa, D.H. Garabrant, et al. (1994)
• Occupational Asbestos Exposure and Incidence of Colon and Rectal Cancers in French Men: The Asbestos-Related Diseases Cohort (ARDCo-Nut) — C. Paris, I. Thaon, et al. (2017)
• Neoplasia among insulation workers in the United States with special reference to intra-abdominal neoplasia — E.C. Hammond, I.J. Selikoff, et al. (1965)
• The role of cytoreductive surgery and hyperthermic intraperitoneal chemotherapy in the treatment of peritoneal carcinomatosis: a systematic review including evidence from Japan — T. Kitai (2021)
• The pathology of mesotheliomata and an analysis of their association with asbestos exposure — D.O. Hourihane (1964)

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