（2）通常内視鏡検査

Diagnostic Imaging for Early Gastric Cancer―Methods and Accuracy of Screening by Conventional Endoscopy

要旨　上部消化管内視鏡検査は，胃癌の発見診断の第一選択として広く臨床にて行われているが，患者にとっては苦痛を伴う検査である．また広い胃の中で内視鏡が観察困難な部位にある病変は発見が容易ではなく，観察困難になりやすい部位を念頭に置き，丁寧に観察する必要がある．また，術者が異常所見を異常と認識しないと病変として認識できないため，どのような所見が異常であるか癌の所見の解析と所見の蓄積が内視鏡医には必要である．内視鏡検査はこのような検査の特性を考慮して行わないと容易に偽陰性を発生させてしまう検査であり，内視鏡医は，内視鏡検査が患者にとって楽で，偽陰性を発生させないように修練していく必要がある．

　Upper endoscopy is commonly used as the first step in clinical screening for gastric cancer. However, it is an uncomfortable examination for the patient. Detection of a lesion in areas that are difficult to observe is laborious and careful inspection of abnormal lesions is essential, especially in the areas that are difficult to observe. The endoscopist must be sufficiently experienced to recognize an abnormal lesion and perform careful analysis. An experienced endoscopist will be aware of the endoscopic properties indicating cancer and thus avoid misdiagnosis and producing a false negative result. The endoscopist must be sufficiently trained to perform the examination with optimal patient comfort and still be thorough and careful enough to prevent false negatives.