陥凹性早期胃癌のIndex法による内視鏡診断；RC法

ENDOSCOPIC DIAGNOSIS OF DEPRESSED TYPE EARLY GASTRIC CANCER BY MEANS OF AN INDEX METHOD: RC METHOD

Ⅰ．はじめに

　早期胃癌の大部分は胃内視鏡で診断がつくようになった．しかし，一部は胃生検なしには確診困難である．確診困難なとき数週間の経過観察で癌としての特徴が出現するのを待つ方法もある¹⁾．経過観察は潰瘍合併のものにとくに有効である．

　陥凹性早期胃癌の短期経過追求の結果，早期胃癌内潰瘍の多くが抗潰瘍治療で治癒傾向を示すことが明らかとなった²⁾．多数例の経過追求は，診断がついてから手術までの間，われわれの病院の機構上やむなく何週間かを要するので，その間を利用して詳細な追求をしていくという方法によって行なわれる．また疑診から確診までの間追求する．胃生検が極めて容易に行なわれる現今では，むしろ確診から手術までの間を利用して追求していく．

　このように追求しているとき，非常にしばしば出現してくる所見として，うすい白苔にかこまれた粘膜の島がある．この島は赤斑としてみえることがある．うすい白苔は撮影条件が悪いとよくみえない．このような所見は悪性潰瘍で極めて頻繁にみられるが，良性潰瘍ではまれにしかみられない．早期胃癌内潰瘍は治癒する傾向があるといってはみても，所詮その再生粘膜はその再生のうしろ側からくずれてきて白苔をかぶったⅡcができてくると老えられるのである．どうやらこういう現象が段々と上記の白苔にかこまれた粘膜の島へと発展していくものの1つではないかと思われる．そこで粘膜の島Redpatchとそれを取りかこむ白苔white CoatingのRとCをとってこの現象をRCと呼ぶことにする．このRCは潰瘍性病変の良悪性鑑別の手がかりになりそうである．

　さらにこれらの島が高まっている場合がある．これをWallと呼ぶ．出血Bleedingおよび周辺粘膜の襞Foldの状態も参考にして，陥凹性早期胃癌の内視鏡診断について述べることにする．

　以上に挙げた各要素をそれぞれの程度別にIndexにして表現し，このIndexによる表現法をRC法と呼ぶことにする．

　なお，各要素以外に実際にはもっと多くのみるべき要素があるが，今回はIndexに表現しやすいものだけについてとりあえず考慮してみたものである．

　It has been established that ulcer within early gastric cancer tends to heal and in the development of cancer it has been found that according as ulcer lesion becomes re-epithelised the floor of Ⅱc typecancer is apt to deepen. Consequently, crater in early gastric cancer is to be considered as different in its evolution from that of advanced cancer.

　In this paper is described an endoscopic evaluation of 300 cases of depressed type early gastric cancer as well as gastric carcinoma (less than 6cm in diameter) of Borrman Ⅱ and Ⅲ type, with the exception of papillary adenocarcinoma, and their findings have been compared with those of some 100 cases of benign ulcer.

　The state of ulcer margin; intermingling of red patch (mucosal island) and white slough around red patch; the degree of rolling-up of wall around ulcer; the manner of abrupt cessation, swelling, and fusion, of mucosal folds in the surrounding mucosa; and bleeding; all these findings are divided, according to their intensity, either into five or six stages, and each is closely correlated with the depth of individual gastric cancer. Those of benign ulcer are in this respect considered as zero.

　As a consequence, it has been found that the state of rolling-up (of mucosal folds) at ulcer margin, and the degree of swelling, and cessation, of mucosal folds in the surrounding mucosa are greatly conducive to the determination of the depth of cancer invasion, and that the state of slough as well as the manner of “red patch” and of bleeding in the surrounding area is of great help in the qualitative diagnosis of gastric cancer. It also has been found that ulcer cratcr found in advanced cancer is, with some exceptions, not formed by enlargement of ulcer lesion in early gastric cancer, but by excavation and dissolution of cancer tissues in Ⅱc part of early gastric cancer. Wall, which surrounds ulcer, reaching in gentle slope from adjacent area up to ulcer margin, is rolled up as a result of deeper penetrating cancer infiltration. Endoscopically, it is sometimes seen as of greater extent than it really is, owing to poor distensibility of the gastric wall. The more profound the penetration of cancer infiltration is, therefore, the deeper ulcer crater looks and the taller surrounding wall seems, as compared with the real state of cancer tissue dissolution.