Bronchoscopic advances: on the way to the cells.

In the past 15 years, new endoscopic methods have been developed in order to improve the detection of early bronchial cancers, with autofluorescence bronchoscopy being the leading technique. However, autofluorescence bronchoscopy is hampered by the low specificity of the fluorescence defect which ranges from 25 to 50%, and its limitation to the proximal bronchial tree from which arise only half of the lung cancers that are currently diagnosed. To overcome these limitations, other techniques emerge including video/autofluorescence bronchoscopy, narrow band imaging, optical coherence tomography, and 'endomicroscopy' using confocal fluorescent laser microscopy. These emerging techniques provide new insight into bronchology, extending the field of exploration from the proximal bronchus down to the most distal part of the lungs, and from macroscopy to in vivo cellular imaging. In the near future, they may enable in vivo, minimally invasive, 'pathological grade' evaluation of abnormal bronchial or parenchymal lung tissue. Whereas promising pioneer work has recently been published, careful assessment is required before these methods find a place in the evaluation strategy of early lung cancer and other lung diseases.