Diagnostic results before and after introduction of autofluorescence bronchoscopy in patients suspected of having lung cancer detected by sputum cytology in lung cancer mass screening

For the purpose of early detection, we have conducted population-based mass screening for lung cancer by sputum cytology since 1982. Although detection of lung cancer in its early stage is important for a good prognosis, it is often difficult to localize lesions in roentgenographically occult cancer. To clarify the role of autofluorescence bronchoscopy in localizing tumors in patients with roentgenographically occult cancer, we analyzed our diagnostic results. Fifty patients who had been detected by sputum cytology were screened by the light-induced fluorescence endoscope (LIFE)-Lung System from November 1997 to April 1999. We compared the results according to the screening methods: conventional bronchoscopy alone versus LIFE with conventional white-light bronchoscopy (November 1997 to April 1999). Twenty-eight cancerous lesions and 39 borderline lesions were detected by LIFE. Of the 39 borderline lesions, nine were detected only by LIFE. Multicentric lesions including cancer or dysplasia were also detected in 21 of the 50 patients by LIFE. The sensitivity by white-light bronchoscopy alone was 85.3%, whereas that of the LIFE-Lung System with white-light bronchoscopy was 94.1% ( P=0.078). There were no cancerous lesions in the area observed as normal by LIFE. We also compared the diagnostic results of two localization methods: brushing of all bronchi (September 1986 to December 1990) and the LIFE-Lung System (November 1997 to April 1999). Although this was a historical comparison, the number of detected borderline lesions increased, which led to a high detection rate in patients with suspected-positive sputum ( P=0.0006) by the LIFE-Lung System. In conclusion, the LIFE-Lung System is a safe and non-invasive system for detecting small intraepithelial lesions of the tracheobronchial tree. Autofluorescence bronchoscopy is more efficacious for localizing intraepithelial lesions and places fewer burdens on the patient than brushing of all bronchi.