Diagnosis of esophagogastric tumors.

There is increasing concern regarding the need to establish guidelines for upper gastrointestinal endoscopy. This applies to the reliability of the diagnosis of early cancer, tolerance, and the need to reduce the use of conscious sedation in order to contain costs--one reason why nasogastroscopy with a thin fiberscope is being applied with increasing success. Recent advances that have been made in the early diagnosis of esophageal and gastric tumors now require high-resolution video gastroscopes and the routine use of chromoscopy. For a long time, the helpful contribution made by the zoom video endoscope to the identification of the pit pattern in neoplastic lesions was limited to the colon. However, the most recent zoom endoscopes, with improved mechanical characteristics and a standard diameter, have now opened up relevant applications in the analysis of early esophageal or gastric malignancies. The best example of this is the identification of the pit pattern in intestinal metaplasia in Barrett's esophagus, although the classification of the pit pattern in upper gastrointestinal neoplasia is still being investigated. Spectroscopic analysis of the response of neoplastic tissue to an applied photon beam has been hampered by the complex origins of the efferent photons. Recent technology, available only through a physical laboratory allows simultaneous analysis of fluorescence, reflectance, and light scattering. In this situation, the method has obtained sensitivity and specificity rates of nearly 100% in classifying low-grade dysplasia, high-grade dysplasia, and cancer in Barrett's esophagus. With regard to depth exploration in the wall of the digestive tract, endosonographic examination using a high-frequency probe (20-30 MHz) may be challenged in the future by the technique of optical coherence tomography, a method that does not require acoustic transmission through water and provides a much higher resolution, of up to 10 microm. Optical coherence tomography could be used in the staging of intramucosal esophageal cancer and for detecting intestinal metaplasia in the esophagus. In conclusion, the increasing progress being made in the accuracy of endoscopic diagnosis emphasizes the need for cost-benefit analyses of screening and surveillance protocols.