早期大腸癌肉眼分類―早期胃癌肉眼分類との整合性を求めて

Macroscopic Typing of Early Colorectal Carcunoma, and Evaluation of the Applicability of Macroscopic Typing of Early Gastric Carcinoma to Early Colorectal Carcinoma

要旨　早期大腸癌の肉眼分類は早期胃癌のそれに準じて行われてきたが，微小な陥凹型病変が多数みつかるようになると，大腸癌独自の発生，発育，進展に注目した分類，肉眼型が提唱されるようになり，混乱が生じている．しかし消化管の腫瘍の肉眼分類は本来，隆起と陥凹を中心にした単純なもので，この基本概念を変更してまで肉眼型分類を複雑化する必要は全くない．基本型の組み合わせで，個々の病変の特質は十分表現可能であり，その意味で早期大腸癌の肉眼分類の基本は早期胃癌の分類に準じて問題はないと考えるが，大腸癌の特殊性を加味することが必要である．

　The high-resolution magnifying colonoscope makes it possible to observe the minute surface structure and to detect many superficial depressed type lesions. Some colonoscopists classify the macroscopic type of colorectal early cancer considering also the histogenesis, development and biological behavior of the tumor. The differences in the quality of observation cause great confusion in macroscopic typing and make it more difficult to apply macroscopic typing of early gastric carcinoma to the colon.

　For the purpose of evaluating the applicability of the macroscopic typing of early gastric carcinoma to early colorectal carcinoma, the macroscopic and pathologic findings of 517 early colorectal carcinomas were analyzed.

　Typing of early gastric carcinoma was found to be also useful for early colorectal carcinoma as long as the histogenesis or behavior of the lesion is excluded. To resolve the confusion, we need to clarify the definition and character of type Ⅱc, superficial depressed type cancers.