Can semi-automated image cytometry on induced sputum become a screening tool for lung cancer? Evaluation of quantitative semi-automated sputum cytometry on radon- and uranium-exposed workers

Our plain-English summary of Can semi-automated image cytometry on induced sputum become a screening tool for lung cancer? Evaluation of quantitative semi-automated sputum cytometry on radon- and uranium-exposed workers, by W. Marek, N. Kotschy-Lang, A. Muti, et al (The European Respiratory Journal, 2001).

The study

• Authors: W. Marek, N. Kotschy-Lang, A. Muti, C.H. Köhler, L. Nielsen, T.H. Topalidis, Z. Atay, J.A. Nakhosteen
• Journal: The European Respiratory Journal
• Published: 2001;18(6):942-50
• Cited by: 20 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The correlations between semi-automated sputum cytometry (ASC), conventional cytology and the final diagnosis was investigated in industrially-exposed workers. Slides of sputum samples from 201 former uranium miners with silicosis, 100 patients with asbestosis, 103 workers resected for lung cancer, and 200 controls (50% smokers), were stained using the Papanicolaou (Pap) method and the Feulgen reaction with thionin. Cytometry was performed using the Cyto-Savant automated system. Atypical nuclei were found in 72 of 404 patient samples, 327 samples were normal and five were inadequate for ASC analysis. Thirteen tumours (Pap IV, Pap V) and 11 cases of severe dysplasia were identified by cytology. Lung cancer was confirmed in 20 patients. Compared to the final diagnosis of lung cancer, the sensitivity of ASC was 75% (15 out of 20) and specificity 89.8% (520 out of 579). The results represent a diagnostic efficiency of 89.3%. The combination of ASC with cytology increased sensitivity to 80% (16 out of 20) without significant loss of specificity (89.7% or 523 out of 581). In this investigation of a limited number of patients with occupational radon or asbestos exposure, semi-automated sputum cytometry appears to be sensitive and reliable for the detection of malignant changes in the tracheobronchial mucosa. Together with conventional cytology, it would be reasonable to test the validity of the combined methods in a large-scale feasibility study of early lung cancer detection.

In plain English

This German study tested whether a semi-automated cytometer, which measures the DNA content and structure of cell nuclei, could detect lung cancer in induced sputum (mucus coughed up after inhaling salt-water mist). Sputum was collected from September 1996 to December 1998 from 201 former uranium miners with silicosis, 100 patients with asbestosis, 103 patients after lung cancer surgery, 100 heavy smokers and 100 nonsmoking controls. Results were compared with conventional cytology and the final diagnosis. Among the 404 patients, 20 had lung cancer or cancer spread from elsewhere at final diagnosis: six had asbestosis and 14 silicosis. One was an advanced pleural mesothelioma. Cytometry identified 15 of the 20 (75.0%, 95% confidence interval 50.9 to 90.3%) and gave false-positive results in 59 of 579 samples. Cytology identified 12 of 20 (60%, 95% confidence interval 36.1 to 80.9%). Combined, the two methods identified 16 of 20 (80%). The authors called their numbers limited and noted that inflammation may cause misreadings. They concluded that the method appears sensitive and reliable, and should be tested with cytology in a large screening 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: Diagnostic accuracy study comparing semi-automated sputum cytometry and conventional cytology against the final diagnosis
• Who was studied: Patients seen for regular checkups at an occupational lung disease hospital in Falkenstein, Germany. They were 201 former uranium miners with silicosis, 100 patients with asbestosis and 103 patients after lung cancer resection. There were also 100 heavy smokers and 100 nonsmoking controls without radon or asbestos exposure. Sputum was collected September 1996 to December 1998.
• Exposure: Occupational radon exposure (former uranium miners with silicosis) and asbestos exposure (patients with asbestosis). Fiber types were not specified. The table lists exposure durations in years.
• Main results:
  • Among the 404 occupationally exposed patients, 20 had cancer at final diagnosis: six had asbestosis and 14 silicosis, and eight had had previous lung cancer resections
  • One of the 20 cancers was an advanced pleural mesothelioma (in a patient with asbestosis, per table 4)
  • Sensitivity of cytometry was 75.0% (15 out of 20 cancers detected)
  • The 95% confidence interval for cytometry sensitivity was 50.9 to 90.3%
  • Cytometry gave false-positive results in 59 of 579 samples (specificity 520 of 579)
  • Sensitivity of conventional cytology was 60% (12 out of 20), with specificity 545 out of 558
  • The 95% confidence interval for cytology sensitivity was 36.1 to 80.9%
  • Cytometry and cytology combined had a sensitivity of 80% (16 out of 20)
  • In the control group, all but two samples from smokers were classified as benign by cytometry, and repeat testing of those two was benign
  • Only five of 604 samples had too little material for cytometry
• The authors' conclusion: The authors concluded that, in a limited number of patients with occupational radon or asbestos exposure, semi-automated sputum cytometry appears sensitive and reliable for detecting malignant changes. They proposed testing it together with cytology in a large-scale feasibility study of early lung cancer detection.
• Limitations the authors state:
  • The study included a limited number of patients
  • Inflammatory changes in nuclear structure may lead to misinterpretation (false positives)
  • A receiver operating curve could not represent the method's true potential, because classification partly relies on a visual impression that cannot be quantified

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: Sputum, Lung Cancer, Cytology, Silicosis, Asbestos Exposure.

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• Asbestos bodies in the sputum of asbestos workers: correlation with occupational exposure — C. Paris, F. Galateau-Salle, et al. (2002)
• Copy number gains on 5p15, 6p11-q11, 7p12, and 8q24 are rare in sputum cells of individuals at high risk of lung cancer — E. Kettunen, K. Salmenkivi, et al. (2006)
• Robust Cell Detection and Segmentation for Image Cytometry Reveal Th17 Cell Heterogeneity — T. Tsujikawa, G. Thibault, et al. (2019)
• Screening for asbestos-induced diseases in Finland — K. Koskinen, J.P. Rinne, et al. (1996)

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