Detection of dysplasia and carcinoma in situ by ratio fluorometry

Our plain-English summary of Detection of dysplasia and carcinoma in situ by ratio fluorometry, by S. Lam, J.Y. Hung, S.M. Kennedy, et al (The American Review of Respiratory Disease, 1992).

The study

• Authors: S. Lam, J.Y. Hung, S.M. Kennedy, J.C. Leriche, S. Vedal, B. Nelems, C.E. Macaulay, B. Palcic
• Journal: The American Review of Respiratory Disease
• Published: 1992;146(6):1458-61
• Cited by: 61 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Fluorescence bronchoscopy was performed in 82 volunteers recruited from occupational groups at risk of exposure to asbestos and/or diesel fumes to determine whether differences in tissue autofluorescence between normal and malignant bronchial tissues can be used to improve the sensitivity of standard fiberoptic bronchoscopy in detecting dysplasic and carcinoma in situ (CIS). This study consisted of 25 nonsmokers, 40 exsmokers, and 17 current smokers with mean ages of 52, 55, and 49 yr, respectively. Tissue autofluorescence was induced by a blue light from an He-Cd laser coupled to the illumination channel of the bronchoscope and analyzed by a ratiofluorometer. One or more sites of moderate or severe dysplasia were found in 12% of the exsmokers and current smokers but in none of the nonsmoker volunteers. CIS was found in two of the exsmokers. The sensitivity of fluorescence bronchoscopy (86%) was found to be 50% better than that of conventional white-light bronchoscopy (52%) in detecting dysplasia and CIS. Pre- and post-bronchoscopy sputum cytology failed to detect these precancerous lesions. Our results suggest that fluorescence bronchoscopy may be an important new method that can improve the ability to detect and localize precancerous and/or CIS lesions.

In plain English

This study tested whether measuring the natural fluorescence of the airway lining under blue laser light (fluorescence bronchoscopy) could find dysplasia (precancerous changes) and carcinoma in situ (CIS, a very early cancer) better than ordinary white-light bronchoscopy. The 82 volunteers came from occupational groups at risk of exposure to asbestos, diesel fumes or both, such as insulators and ship maintenance workers. There were 25 nonsmokers, 40 ex-smokers and 17 current smokers. No nonsmoker had moderate dysplasia or worse. Moderate dysplasia was found in three current smokers and one ex-smoker, severe dysplasia in two ex-smokers and one current smoker, and CIS in two ex-smokers. Neither smoking status nor occupational group (diesel versus asbestos exposed) significantly predicted these findings. For moderate dysplasia or worse, fluorescence bronchoscopy had a sensitivity of 86%, compared with 52% for white light. Sputum tests detected none of these lesions. The authors concluded that fluorescence bronchoscopy may improve detection of such lesions. They noted that the volunteers were self-selected and that the study was not designed to examine links between lung cancer and workplace exposures.

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 comparison study: every volunteer had both white-light and fluorescence (ratio fluorometry) bronchoscopy, with biopsies read by one pathologist who did not know the bronchoscopy findings
• Who was studied: 82 volunteers from occupational groups at risk of asbestos and/or diesel exposure: 25 nonsmokers, 40 exsmokers and 17 current smokers, with mean ages of 52, 55 and 49 years respectively; study dates not given
• Exposure: Occupational exposure risk to asbestos, diesel fumes, or both, in groups such as insulators, ship maintenance workers and engineers, and ferry car/truck deck workers; no fiber types or exposure levels were reported
• Main results:
  • No nonsmoker had moderate dysplasia or worse
  • Moderate dysplasia was found in 3 of 17 current smokers and 1 of 40 exsmokers
  • Severe (marked) dysplasia was found in two exsmokers and one current smoker; CIS was found in two exsmokers
  • Neither smoking status nor occupational group (diesel exposed versus asbestos exposed) was a significant predictor of bronchoscopy outcome
  • Across 238 biopsies, red-to-green fluorescence ratios from areas with moderate dysplasia, severe dysplasia and CIS were significantly higher than those from normal areas (p less than 0.05)
  • For detecting dysplasia and CIS, sensitivity was 86% for fluorescence bronchoscopy and 52% for white-light bronchoscopy (Table 4: moderate dysplasia or higher)
  • The gain in sensitivity came with a similar level of specificity
  • The sensitivity difference was statistically significant (p less than 0.05) when mild or moderate dysplasia was the cut-off
  • For severe dysplasia and CIS, the difference was of similar size, but there were too few cases to test statistically
  • Sputum cytology before and after bronchoscopy showed mild dysplasia in 8.2% of subjects and detected none of the moderate dysplasia, severe dysplasia or CIS lesions
• The authors' conclusion: The authors concluded that fluorescence bronchoscopy may be a new method that can improve the ability to detect and localize precancerous and/or CIS lesions
• Limitations the authors state:
  • Participants were self-selected and not necessarily representative of these occupational groups
  • Too few cases of severe dysplasia and CIS for statistical testing
  • The study was not designed to establish or confirm an association between lung cancer and exposure to known or potential carcinogens
  • As a non-imaging method, the exact source of a positive signal cannot be pinpointed
  • The single-probe design can miss small early cancers
  • The device must be calibrated on a presumed normal site; if that site is abnormal, detection of CIS may be reduced

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: Carcinoma, Bronchoscopy, Sputum, Cytology.

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