[Optical diagnosis of cervical dysplasia]

Cervix cancer is a curable disease when diagnosed at an early stage. Screening of cervical lesions by cytology and colposcopy with in situ staining has allowed for substantial progress in early diagnosis and consequently the cure of cervix cancer. Nevertheless, because of its low specificity, this approach generally implies repetitive tissue sampling and, thus a relative long time before the treatment of the lesions. Furthermore, the cost of preparation and analysis of biopsy samples is sufficiently high to represent a burden for industrialized countries and a virtual impossibility for the developing world. To overcome these problems, various biophotonic methods using optical fibers have been developed to allow for detection of cervical epithelial anomalies in a specific, fast and non-invasive way. This process, known as "optical biopsy", is based on the measurement of light-tissue interactions, which are analysed by various mathematical and data processing methods, to provide information on the metabolism and morphology of epithelial tissue. Currently investigated methods can be distinguished according to the type of signal used to probe the tissue (fluorescence, reflectance), the depth of analysed tissue (surface analysis, confocal imaging, tomography), the analysis modalities (spectral measurements or imaging), and the use of additive molecules (contrasting or photosensitizing agents, inorganic fluorophores). While most of the methods remain experimental, constant progress in the understanding of the mechanisms of light behavior in biological environments as well as advances in optical fibers technology, will make a number of these methods soon available for clinical practice to contribute efficiently to the reduction of biopsy number and cost of cervical screening.