Abstract
We examined 12,014 cases of for gastric cancer screening health checkups with transnasal ultrathin endoscope from April 2005 through August 2010, and 30 cases of gastric cancer were detected. Among these, we defined eight cases (nine cancer lesions), who had undergone transnasal endoscopic screening at our institution within three years before the detection of gastric cancer, as false-negative cases. The clinicopathological findings of 8 cases (9 cancer lesions) showed that the rate of early cancer was 88.9%, and 37.5% of them were treated by endoscopic resection. Compared to the previous screening results of the endoscopic images of these cases, we determined that 3 cases had been simply overlooked and 4 cases had been poorly examined. Also, there was 1 case which was difficult to detect. Especially, the lesions located at the greater curvature of the U and M regions were missed, even by skilled endoscopists with 5 years or more experiences. The false-negative rate was 26.7% (8/30). If eliminating the one difficult case, the rate would be 23.3%. These results are similar to those reported by others using the regular-sized oral endoscope. Thus, we conclude that transnasal endoscopy is not inferior to regular-sized oral endoscopy for gastric cancer screening. For a further multi-center prospective study, we need to standardize the definition of false-negative, and to establish a standardized observation method utilizing chromoendoscopy with indigo carmine dye.
