Factors in Lung Cancer

Our plain-English summary of Factors in Lung Cancer, by L. Breslow, L. Hoaglin, G. Rasmussen, et al (1954).

The study

• Authors: L. Breslow, L. Hoaglin, G. Rasmussen, H. K. Abrams
• Published: American Journal of Public Health, Vol. 44, No. 2, February 1954
• Type of article: Journal article
• Our copy: from Johns-Manville's own medical library. The article is still under copyright, so we describe it here rather than post it.

In plain English

This 1954 study by Breslow and colleagues compared 518 patients whose lung cancer was proved by tissue examination, seen in 11 California hospitals, with 518 hospital patients matched by age, sex and race who were admitted for conditions other than cancer or chest disease. Interviewers recorded each person's lifelong work history and tobacco use. Ninety-three per cent of the lung cancer patients had smoked cigarettes, compared with 76 per cent of the controls. Over the preceding 20 years, 74 per cent of patients and 42 per cent of controls had smoked one or more packs a day. On asbestos, the authors looked at a group that included steam fitters (16 cases and 10 controls with at least five years' employment). They found that substantially all of the case-control difference in that group was due to steam fitters with heavy asbestos exposure. Among people employed at least five years as steam fitters, boilermakers or asbestos workers, there were 10 cases and 1 control. Once smoking was taken into account, this result lay on the borderline of statistical significance. Welding appeared to act separately from smoking. The authors noted small numbers and concluded that the occupations they identified deserve intensive study.

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: lung cancer patients and matched hospital control patients were interviewed about lifelong occupational and tobacco-usage history
• Who was studied: 518 patients with histopathologically proved lung cancer (493 male, 25 female) in 11 California hospitals. The controls were 518 patients admitted about the same time, matched on age (within five years), sex and race, who had conditions other than cancer or chest disease. The years of study are unreadable in the scan.
• Exposure: Lifelong occupations, coded into 367 categories with attention to years of employment, and tobacco use (type and amount). Asbestos exposure was examined through steam fitters, boilermakers and asbestos workers. The article does not name a fiber type.
• Main results:
  • 93 per cent of the lung cancer patients had histories of smoking cigarettes
  • 76 per cent of the controls had a history of smoking cigarettes
  • 74 per cent of lung cancer patients reported smoking one or more packs of cigarettes per day on average over the preceding 20 years. The corresponding figure for controls was 42 per cent.
  • The correlation between cigarette smoking and lung cancer increased steadily with the amount smoked
  • Applying Cornfield's formula to four studies including this one, the authors estimated that for men aged 50-59 the prevalence of lung cancer was four to 11 times as great among smokers as among nonsmokers
  • In the same four-study estimate for men aged 50-59, the prevalence was seven to 27 times as great among heavy smokers as among nonsmokers. Similar ratios were found for ages 60-69.
  • 6 of 46 adenocarcinoma cases (13 per cent) did not smoke cigarettes, compared with 28 of 472 patients (6 per cent) with other types of carcinoma
  • In an occupational group including steam fitters, there were 16 cases and 10 controls with a five-year employment history. Substantially all the case-control difference in that group was due to steam fitters who had heavy asbestos exposure.
  • Among people employed at least 5 years as steam fitters, boilermakers or asbestos workers, there were 10 cases and 1 control
  • When cigarette smoking was controlled, the steam fitter, boilermaker and asbestos worker group lay on the borderline of statistical significance
  • The analysis indicated that welding operated as a factor distinct from cigarette smoking in relation to lung cancer
  • For the other occupational groups, the authors said the differences might have arisen from chance variation more than five times in a number of trials. That number is lost in the scan.
• The authors' conclusion: The authors concluded that the occupations they singled out, including the steam fitter, boilermaker and asbestos worker group, deserve intensive study to determine their precise relationship to lung cancer. They also said their smoking data parallel other studies showing a correlation that rises with the amount smoked.
• Limitations the authors state:
  • Small numbers for many of the occupations
  • The occupation code was arbitrary and not designed to reflect common exposures that might cause lung cancer
  • The Cornfield estimates assume that patients and controls are representative samples of all lung cancer cases and all other persons in the population

Topics

Medical terms in this study, explained in our Lexicon: Lung Cancer, Occupational History, Asbestos Exposure, Statistical Significance.

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