Follow-up of bronchial precancerous lesions and carcinoma in situ using fluorescence endoscopy.

Little is known about the natural history of precancerous bronchial lesions. Histological changes occurring in 416 bronchial intraepithelial lesions (104 high-risk subjects) were assessed over a 2-yr period, using repeated follow-up autofluorescence endoscopies. During the study, 6 of 36 normal epitheliums became dysplastic; 47 of 152 metaplasia evolved to low-grade dysplasia, two progressed to carcinoma in situ, and one to invasive cancer; 6 of 169 low-grade epithelial lesions progressed to a persistent severe dysplasia; 10 of 27 severe dysplastic lesions and 28 of 32 carcinoma in situ persisted or progressed, respectively (p = 0.0005, severe dysplasia versus carcinoma in situ 24 mo outcome). Carcinoma in situ appeared more frequent in patients with a prior history or concomitant cancer (p = 0.003). Persistence of smoking during the study did not influence high-grade lesion outcome. Progression of low-grade epithelial lesions during the study occurred only in patients with at least a high-grade lesion in another site at baseline (9 of 147 lesions, 6.1%). Our study suggests that low-grade epithelial lesions could be safely followed-up at 2 yr in patients without high-grade lesions at baseline, whereas severe dysplasia should be treated if they persist at 3 mo. Immediate treatment of carcinoma in situ appears warranted.