Fluorescein electronic endoscopy: a novel method for detection of early stage gastric cancer not evident to routine endoscopy.

BACKGROUND Fluorescence endoscopy with fluorescein sodium in the stomach was evaluated by using a newly developed fluorescence electronic endoscopic system. METHODS Sixteen patients with early stage gastric cancer diagnosed by white light endoscopy and chromoendoscopy underwent fluorescein electronic endoscopy before surgery. The resection specimens underwent thorough histopathologic evaluation. RESULTS About 10 seconds after intravenous injection of fluorescein, fluorescence appeared and immediately spread throughout the gastric surface. A few minutes later, differentiated early stage gastric cancers with more abundant stroma than surrounding normal mucosa exhibited significantly stronger fluorescence, and those with less stroma exhibited weaker fluorescence than the surrounding normal mucosa. Undifferentiated early stage gastric cancers, in which the stroma became wider because foveolae were collapsed from malignant invasion, expressed stronger fluorescence intensity. In all cases, the borders of early stage gastric cancers were clearly demonstrated. Among the 16 patients, 6 accompanying flat lesions and 1 tiny lesion not evident by routine endoscopy were detected. The extent of the cancers, as determined by fluorescence endoscopy, were similar to those determined histopathologically. CONCLUSIONS Fluorescein electronic endoscopy is useful in determining the extent within the mucosa of gastric cancers when this is obscure by standard endoscopic observation, and for detecting extremely early stage cancer that is not evident by conventional endoscopic observation.