胃癌の新肉眼分類における使用上の留意点―病理の立場から

A New Macroscopic Classification of Gastric Cancer: From Pathological Stand Point

要旨　新しい胃癌の肉眼分類を旧分類と比較して検討した．新肉眼分類の改訂点は，第1には粘膜面の“かたち”のままを表現した分類で，従来の早期癌と進行癌に分けたうえでの肉眼分類とは異なる点であり，第2には臨床所見・手術所見・総合所見に分けて記載し，肉眼型にその時点での深達度を付記する点である．実際の分類では，従来の1～4型に属するものや早期癌類似進行癌としたものは，今回の分類で，ある程度の旧分類からの読み替えもでき，総合所見単独あるいは手術所見と総合所見を合わせると十分に肉眼の形態を表現することができた．しかしながら，従来の早期癌分類でⅠ型に，あるいはⅢ型に分類した症例で，隆起が高いもの，あるいは陥凹の深いものは，それぞれ1型，2～3型に肉眼で見たままを表現し分類するという点については，従来の分類からの読み替えは困難であり，どの程度までを1型あるいはⅢ型に分類するか各施設問での調整の必要があると思われた．

　We discuss a new macroscopic classification of gastric cancer and compare it with the former one.

　The new macroscopic classification separates the tumors into five types: type 0 for superficial tumors, type 1 for protruded tumors, type 2 for ulcerative and localized tumors, type 3 for ulcerative and infiltrative tumors, type 4 for diffusely infiltrative tumors and type 5 for miscellaneous tumors. There are two major revised points, one is that the new classification is made solely on the basis of macroscopic features. The other is that the classification is made three times based on the clinical, surgical and the final pathological findings. Practically, type 1～4, type Ⅱa, type Ⅲ and so-called early gastric cancer like advernced cancer of the former classification were easily able to be fitted into new classification, but type Ⅰ early gastric cancer and advanced cancer like early cancer of the former classification were difficult to fit into the new classification. The new classification is a suitable one that can represent almost all macrosopic types of gastric cancer. We feel that, among pathologists, this new classification will prevail in the near feature among pathologists.