Yield of Low-Dose Computerized Tomography Screening for Lung Cancer in High-Risk Workers: The Case of 7189 US Nuclear Weapons Workers

Our plain-English summary of Yield of Low-Dose Computerized Tomography Screening for Lung Cancer in High-Risk Workers: The Case of 7189 US Nuclear Weapons Workers, by S.B. Markowitz, A. Manowitz, J.A. Miller, et al (American Journal of Public Health, 2018).

The study

• Authors: S.B. Markowitz, A. Manowitz, J.A. Miller, J.S. Frederick, A.C. Onyekelu-Eze, S.A. Widman, L.D. Pepper, A. Miller
• Journal: American Journal of Public Health
• Published: 2018;108(10):1296-1302
• Cited by: 22 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Objectives: To determine the lung cancer screening yield and stages in a union-sponsored low-dose computerized tomography scan program for nuclear weapons workers with diverse ages, smoking histories, and occupations.

Methods: We implemented a low-dose computerized tomography program among 7189 nuclear weapons workers in 9 nonmetropolitan US communities during 2000 to 2013. Eligibility criteria included age, smoking, occupation, radiographic asbestos-related fibrosis, and a positive beryllium lymphocyte proliferation test.

Results: The proportion with screen-detected lung cancer among smokers aged 50 years or older was 0.83% at baseline and 0.51% on annual scan. Of 80 lung cancers, 59% (n = 47) were stage I, and 10% (n = 8) were stage II. Screening yields of study subpopulations who met the National Lung Screening Trial or the National Comprehensive Cancer Network Group 2 eligibility criteria were similar to those found in the National Lung Screening Trial.

Conclusions: Computerized tomography screening for lung cancer among high-risk workers leads to a favorable yield of early-stage lung cancers. Public Health Implications. Health equity and efficiency dictate that screening high-risk workers for lung cancer should be an important public health priority.

In plain English

This report described a union-sponsored low-dose CT screening program for lung cancer among 7189 former US nuclear weapons workers. All were aged 50 or older, had ever smoked, and worked at 9 Department of Energy sites in 5 states. Scans ran from 2000 to 2013. On the first (baseline) scan, lung cancer was found in 60 of 7189 participants (0.83%). On a one-time scan about a year later, it was found in 20 of 3760 (0.53%). Detection was higher with older age, current smoking and more pack-years, and lower with longer time since quitting. Workers whose chest x-rays showed asbestos-related scarring of the lung or pleura had higher detection rates, but the difference was not statistically significant. After adjusting for age and smoking, rates did not differ significantly by job category. Of the cancers found, 57% (baseline) and 65% (annual) were stage I. Workers meeting the National Lung Screening Trial criteria had rates statistically similar to that trial's. The authors concluded that occupation can be combined with age and smoking to select people for screening. They noted they lacked specific exposure information and mortality data.

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: Report of a community-based, voluntary, union-sponsored low-dose CT lung cancer screening program (baseline scan plus a one-time annual scan), within an occupational medicine screening program
• Who was studied: 7189 former US nuclear weapons production, testing and research workers, aged 50 or older, who had smoked for 1 year or longer. They worked at 9 Department of Energy sites in 5 states, mostly in nonmetropolitan communities. Baseline scans were completed 2000 to March 31, 2013. Participants were 88% male, 93% White, with a mean age of 65; 20.4% currently smoked.
• Exposure: Work at nuclear weapons sites with varied chemical, mineral and radiologic exposures. Exposure was not measured; workers were grouped by job category (maintenance, operations or production supervision, engineering, administration or services). Other factors studied were chest x-ray evidence of asbestos-related parenchymal or pleural fibrosis, beryllium sensitization, age and smoking. No asbestos fiber type is named.
• Main results:
  • Lung cancer was detected in 60 of 7189 participants (0.83%) on the baseline scan and in 20 of 3760 (0.53%) on the annual scan.
  • On the baseline scan, lung cancer detection increased with advancing age, current smoking and greater pack-years, and with fewer years since quitting.
  • Current smokers had a screening yield 3 times (baseline) and 5 times (annual) higher than former smokers. At baseline the rates were 24 of 1468 (1.63%) for current smokers versus 36 of 5721 (0.63%) for former smokers.
  • Baseline yield by chest x-ray finding among the 6415 participants with x-rays: 3 of 168 (1.79%) with parenchymal disease, 7 of 532 (1.32%) with pleural disease only, and 47 of 5715 (0.82%) with no fibrosis. The increase was not statistically significant.
  • After adjustment for age and smoking, lung cancer yield did not differ significantly among occupational categories.
  • Workers with abnormal beryllium lymphocyte proliferation tests did not have an increased lung cancer screening yield.
  • Of the cancers found on baseline and annual scans, 57% and 65% respectively were stage I (one was carcinoma in situ).
  • Of the cancers found on baseline and annual scans, 12% and 5% respectively were stage II.
  • Participants meeting National Lung Screening Trial criteria (20.5% of the study population) had yields of 1.5% at baseline and 1.2% at annual scan. The trial's yields were 1.03% and 0.68%. The authors described these as statistically similar.
  • 3739 participants (52.0%) met neither the National Lung Screening Trial nor the NCCN Group 2 criteria. Their yields were significantly lower than the trial's: 11 of 3739 (0.29%) at baseline and 6 of 2100 (0.29%) at annual scan.
  • Among participants aged 80 or older, lung cancer was found on the baseline scan in about 1 of every 66 (7 of 465).
• The authors' conclusion: The authors concluded that occupation can be used together with age and smoking to identify groups with a screening yield and stage distribution similar to the National Lung Screening Trial. They also concluded that low-dose CT screening is useful for blue-collar workers in nonmetropolitan settings.
• Limitations the authors state:
  • Lack of specific knowledge about occupational exposures
  • No radiation exposure history could be characterized
  • Asbestos exposure history was not reliably identified, apart from fibrosis seen on x-ray
  • No mortality follow-up data
  • Limited statistical power because lung cancer was relatively infrequent
  • The nonrandomly selected population limits inferences about Department of Energy workers generally
  • Mostly male cohort limits generalizability
  • Scan reading centralized to one radiologist may limit generalizability
  • Findings for people aged 80 or older are based on small numbers

Topics

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

Medical terms in this study, explained in our Lexicon: Lung Cancer, Low-Dose CT Screening, Fibrosis.

Related studies

• Comparison of x-ray films and low-dose computed tomographic scans: demonstration of asbestos-related changes in 2760 nuclear weapons workers screened for lung cancer — A. Miller, S.A. Widman, et al. (2013)
• Risk and significance of chest radiograph and pulmonary function abnormalities in an elderly cohort of former nuclear weapons workers — M.A. Mikulski, P.G. Hartley, et al. (2011)
• Diagnostic Performance of Ultra-Low-Dose Computed Tomography for Detecting Asbestos-Related Pleuropulmonary Diseases: Prospective Study in a Screening Setting — M. Schaal, F. Severac, et al. (2016)
• Mortality and cancer incidence of Australian participants in the British nuclear tests in Australia — R.T. Gun, J. Parsons, et al. (2008)
• Computerized tomography scanning and the planning of high-dose radiotherapy for pleural mesothelioma: a report of five patients — P.B. Bricout, M.J. Engler (1981)
• Mortality among U.S. military participants at eight aboveground nuclear weapons test series — J.D. Boice, S.S. Cohen, et al. (2022)

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