Beyond white light endoscopy--the prospect for endoscopic optical biopsy.

The most important factor in the successful treatment of cancer is early detection. This will be more likely to facilitate eradication of abnormal cells prior to systemic invasion. White light endoscopy has been an essential tool in medical diagnosis for a number of years. Direct endoscopic inspection of gastrointestinal organs has revolutionised diagnostic techniques, improving the targeting of biopsies of macroscopic morphological abnormalities. Recent technological developments are threatening a further revolution enabling the instantaneous and non-invasive diagnosis of microscopic tissue abnormalities in vivo. This is made possible by improving the level of information that can be obtained from the tissue. As well as the two-dimensional surface morphology image, which the traditional endoscope can view, new techniques enable structure at depth, i.e., the third-dimension, to be imaged in high resolution. Other advances enable the detection of biochemical changes in tissue that precede any changes in morphology, thus enabling earlier diagnosis of tissue abnormalities. This review details recent advances that have the greatest potential, for use in partnership with endoscopy, for the diagnosis of malignancy and pre-malignancy.