胃癌肉眼分類の問題点―早期胃癌類似進行癌を中心として

Controversial Problems on Macroscopic Classification of Advanced Gastric Cancer Mimicking Early Cancer

要旨　深達度がpm以上になってもなお早期胃癌の癌型を保っている症例がみられ，これらの203例を早期胃癌類似進行癌として検討した．また，pmについては肉眼的に早期癌と鑑別不可能なpm₁と鑑別可能なpm₂とに亜分類した．早期胃癌肉眼分類に準じて分類した肉眼型は，Ⅱc139例，Ⅱc＋Ⅲ48例であり，ⅡcとⅡc＋Ⅲとで187例（92.1％）を占めている．組織型を高分化型，低分化型とに2大別した内訳は，高分化型65例，低分化型127例であり，低分化型が多かった．間質結合織量の多いスキルスが60例（29.6％）にみられた．治癒切除例のリンパ節転移率は，pm₁ 11.8％，pm₂ 43.2％，ss 43.7％，se 56.8％であり，5生率はそれぞれ98.0，89.7，80.7，69.8％であり，深達度につれて低下しているがBorrmann型と比べて高率であった．以上，早期胃癌類似進行癌には多くの特徴がみられるので，これらを1つの症例群として独立させることは有意義である．

　Two hundred and three patients with advanced gastric cancer mimicking early cancer were studied. They accounted for 10.3% of all patients with advanced gastric cancer.

　These 203 cases were subdivided into 3 types according to the rules of macroscopic classification of early gastric cancer defined by the Japan Gastroenterological Endoscopy Society. As a result, 187 (92.1%) were classified as type Ⅱc or type Ⅱc+Ⅲ.

　Histological examination, on the other hand, showed cancer invasion reaching to the muscularis propria in 136 (67.0%), the subserosa in 17 (8.4%) and beyond the subserosa in 50 (24.6%) out of the 203 cases. Scirrhous type was found in 60 (29.6%) cases. Of 192 cases who underwent curative gastrectomy, 127 (66.1%) were classified as poorly differentiated type. Lymph node rnetastases were observed in 73 (38.0%) cases. The five year survival rate of the patients who underwent curative gastrectomy was 85.0%.

　In conclusion, advanced gastric cancer mimicking early cancer has many histological characteristics and better prognosis than so-called Borrmann type one.