[in Japanese]

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We conducted a study in order to categorize mucosal patterns in the stomach, which appear in images taken by the radiological double contrast method, and to codify these categorized mucosal patterns. The relationship between the mucosal patterns of the stomach categorized through the method mentioned above and gastric cancer was investigated in a mass survey. An investigation lasting 10 years was performed on about 2, 000 male subjects. Stomach mucosal patterns vary from one individual to another, but, since individual mucosal patterns were found to be rather stable over the 10-year period, it was possible to categorize the mucosal patterns into 6 categories according to the width of the mucosal fold and the local gastric area.
1. Mucosal patterns were categorized into two large groups: in the first group, the width of the mucosal fold was 4mm or greater, and in the second group, the width of the mucosal fold was less than 4mm. Also, the latter group was further divided into two sub-groups: α1, in which there was no local area with a mucosal pattern greater than 1mm, and β1, in which there was an area with a mucosal pattern greater than 1mm. Approximately one tenth of the subjects in each group were usually observed to have one to several, or even many, small gastric fundal gland polyps, but these polyps were benign.
2. The patterns β, β20, and β3 were observed to have an area with a fold width of more than 4mm, while the pattern β0 had no fold. All stomach cancer cases we experienced during a period of 18 years since 1988 were observed to belong to the group in which the mucosal pattern had local areas of wide folds. In addition, the development of ulceration was frequently detected among the subjects in these groups. Also, examinations of the stomach using an endoscope revealed helicobacter pylori infection in the stomach.

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Current outcomes and characteristics of false-negative lesions were analyzed in order to search for the possibility of implementing endoscopic mass screening gastric cancer, based on 271 cases of gastric epithelial tumor (cancer and adenoma) that had been experienced in a period of three years from 2002 to 2004 at the Foundation for Detection of Early Gastric Carcinoma and Tokyo Health Service Association. These cases included 230 cases of gastric cancer (84.9%), and 41 cases of gastric adenoma (15.1%). In 30.0% (69/230) of gastric cancer the result of the diagnosis that was based only on endoscopic observation did not correspond to that of the final pretreatment diagnosis including the result of biopsy. Such a disagreement was frequently seen in cases of the depressd early cancer with differentiated histological type.
A false-negative lesion was defined as such a cancer that was not detected within three years of the initial endoscopic examination. Following this definition, 62 cases of 242 gastric cancers had escaped the detection, and the false negative rate was estimated to be 25.6%. The oversight of the cases was caused by insufficient endoscopic observation in 83.9% (58/62), and process related to the histological diagnosis of the biopsy specimen in 14.7% (10/62).
The distributions of the falsely negative cases were approximate to those in which the diagnosis based on endoscopic observation did not agree with the final pretreatment diagnosis. The majority of those cases that showed the disagreement ware located in the lesser curvature of the middle portion of the stomach.
Review of both endoscopic images and biopsy specimens was found to be important in order to analyze the diagnostic procedure and correct the diagnosis when the endoscopic diagnosis did not agree with that of biopsy. For this purpose, detailed description of endoscopic findings is required, and the actual status of the endoscopic diagnosis based on the observation are to be clarified.

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We calculated the sensitivity of the fecal occult blood test (FOBT) for advanced colorectal cancers and examined the features and problems associated with false-negative FOBT advanced colorectal cancer (FNFCC) cases detected between 1988 and 2002, using our worksite database. We evaluated the studies in two ways: 1) FNFCC was defined as an interval cancer, and 2) FNFCC was defined to include interval cancers and those cases found by the mass screening. Then, the sensitivity of the FOBT for the former definition was 86.5% over 2 years of testing, whereas that for the latter was 31.8%. As for the cumulative survival rate calculated by the Kaplan-Meier method, it was significantly lower for the former definition than that of the FOBT-positive advanced cancer group (FPFCC). Furthermore, the mortality risk for FNFCC obtained using Coxas proportional hazard model was significantly higher than that for FPFCC. Provided that FPFCC was included in the category of FNFCC for the previous screening round within two years as well as into the category of interval cancers, the sensitivity of the FOBT was 30%. but the cumulative survival rate and mortality risk showed no significance.
We came to the conclusion that interval cancers should be included in the category of FNFCC in the quality management for colorectal cancer screening programs.

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We studied the usefulness of transnasal endoscopy using a very thin endoscope in mass screenings for stomach cancer at the Kansai Occupational Health Association. From May 2004 to July 2005, 28, 510 subjects (22,106 upper GI series, 6,404 upper GI endoscopy) were screened for stomach cancer. The cancer detection rate by upper GI endoscopy was almost 1.5 times that by upper GI series. From a survey of 396 subjects undergoing tansnasal endoscopy, 72% felt less discomfort with the transnasal method, while only 20% felt that the peroral method was less uncomfortable. Subjects who selected transnasal endoscopy as their preferred method the next year accounted for 85%. Epistaxis, an important adverse effect of transnasal endoscopy, was recognized only in 4.1%. Thus, transnasal endoscopy was thought to be safer and easier to implement than peroral endoscopy, and is a useful method in screening for stomach cancer.

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