Early detection of lung cancer with laser-induced fluorescence endoscopy and spectrofluorometry

Study objectives: We performed a clinical trial of laser-induced fluorescen ce endoscopy (LIFE) for detection of precancerous lesions and cancer includ ing carcinoma in situ (CIS), which are difficult to detect by white-light b ronchoscopy. Design: Results with LIFE were compared with the criterion standard, white- light bronchoscopy. The evaluation of these endoscopic results spectrofluor ometrically was examined, and pixels of LIFE images composed of digital sig nals for the intensities of red and green were analyzed. Setting: Tertiary-level hospital treating referrals and subjects with suspi cious results in mass screening. Patients: We examined 65 subjects with suspected lung cancer by both method s, and performed biopsy on 216 lesions. Results: The accuracy of diagnosis by white-light bronchoscopy, with histop athologic results as the standard, was 48.6%. The accuracy by LIFE was 72.7 %. The sensitivity of conventional bronchoscopy for detection of severe dys plasia (21 biopsy specimens) or cancer (28 biopsy specimens) was 61.2% and specificity was 85.0%. With results by LIFE added, these values were 89.8% and 78.4%, respectively. Of nine patients with CIS, only LIFE showed one le sion, and only LIFE showed the extent of seven of the lesions. The autofluo rescence of eight lesions was measured spectrofluorometrically; normal bron chial tissue, severe dysplasia, and cancerous tissue had spectral differenc es. The red/green intensity of cancers on histograms of LIFE images general ly was greater than the ratios for metaplasia or normal bronchial wall. Conclusions: Use of both methods should facilitate early detection. Evaluat ion by spectrofluorometry and analysis of digital signal intensity of resul ts by LIFE make results more objective.