Novel zoom endoscopy technique for diagnosis of small flat gastric cancer: a prospective, blind study

During gastroscopy we frequently encounter flat reddened lesions in the stomach. Making a correct diagnosis of flat small early gastric cancer is dependent not on endoscopic diagnosis, but on histopathologic diagnosis of biopsy specimens alone. We investigated the diagnostic accuracy of magnified endoscopic findings for differentiating between reddened mucosa caused by gastritis and flat reddened gastric cancer, prospectively and blindly.

A total of 603 consecutive patients were examined by upper-gastrointestinal zoom endoscopy and the prevalence of each of the following magnified endoscopic findings, which already had been reported as characteristic for differentiated carcinoma, was recorded: (1) presence of a demarcation line between the reddened lesion and the surrounding mucosa, (2) disappearance of the regular subepithelial capillary network pattern, and (3) presence of an irregular microvascular pattern within the flat reddened lesion. Patients with known gastric carcinomas were excluded from this study.

A total of 158 flat reddened lesions from 158 patients were detected. Pathologically, 144 flat reddened lesions showed only gastritis, whereas 14 lesions were newly diagnosed as carcinoma. Regarding diagnostic accuracy for carcinoma, the negative predictive values of the presence of a demarcation line and disappearance of the regular subepithelial capillary network pattern were 100% and 100%, respectively, and the diagnostic accuracy of the irregular microvascular pattern was 98.7%.

The novel zoom endoscopic findings based on microvascular architecture are very useful for making a differential diagnosis between flat early gastric carcinoma and gastritis.