早期胃癌の変貌―内視鏡診断の立場から

Does Early Gastric Cancer Really Look Defferent from What It Used to Be?: From the view point of endoscopic diagnosis

　1972年に定められた早期胃癌の肉眼分類¹⁾（Fig. 1）に基づいて，われわれの病院における早期胃癌症例（Table 1）を検討すると，それから当分の間（生検の普及期まで），発見された早期胃癌は教科書的な典型的なものが大多数であった．例えば，集中する粘膜ひだの末端に全周性に蚕しょく像が認められるⅡc²⁾などが挙げられる．われわれはかかるものを一応，古典的早期胃癌と呼んでいる．それに対して，近年は非典型的なタイプの早期胃癌，すなわち，肉眼的に悪性所見の認めがたい早期胃癌の比率が増加している．例えば，集中する粘膜ひだの末端の蚕しょく像が部分的にしか認められないもの，それが全く認められないものやわれわれが言う胃炎類似癌³⁾（m，smはⅡb～類似Ⅱbに属する）などが挙げられる．

　なお，早期胃癌のタイプ別，大きさ別や部位別変貌などについては，本号の当院ひろ田論文⁴⁾に譲る．

　Recently I have an impression that macroscopic and morphological types of the early gastric cancer are said to look different from what they uced to. As it is said that epidemiologically there are no great changes in circumstances of cancer evolution among the Japanese, my impression is based on the progress of endoscopic instruments and accumulated knowledge of diagnostics in this field.

　The surface of the lens in GTF types can now be washed with water, and since they have become singlelens cameras, a more precise view and pictures of the mucosal surface of the stomach can now be obtained. We can observe better. Excellent panendoscopes have been developed. Gastric biopsy has made progress and has come to have wider use. All these factors contribute to the progress of endoscopic instruments and knowledge obtained thereby.

　Retrospective studies of endoscopic pictures have made it possible to elucidate greatly the incipient stage of gastric cancer and its natural history.

　Conventional diagnostic criteria for the early cancer of the stomach established in 1972 are already under reform by the progress in diagnostic and biopsy measures. In other words, gastric cancer is now detected by biopsy out of lesions in earlier stages, hard to discreminate whether macroscopically it is benign or malignant.

　I believe that changes in appearance of the early gastric cancer are no more than superficial. Cancers are merely detected and diagnosed in earlier stages as such.