Ⅲ型早期胃癌について

Studies on Ulcer Cancer “Type-Ⅲ Early Gastric Cancer”

　昭和37年早期胃癌の全国集計が施行せられ同時にその内視鏡分類が制定されてから10年を迎えようとしている．この間胃潰瘍と癌の問題も潰瘍が先行か，粘膜癌が潰瘍化するのかの論争となり，またその経過観察の上からも所謂悪性サイクルの観念が現われる等色々の事柄が出てきた．早期胃癌の分類についても内視鏡分類が今日では普遍化されて参ったが，必ずしも満足なものとは言えない．とくにⅢ型早期胃癌というものについては私は今日なおかなりの抵抗を感じているものである．以下このような点に関してⅢ型早期胃癌についての私の考えを説述したい．

　The excavated type of early gastric cancer (Type-Ⅲ) has been considered “ulcer cancer” in which cancer development follows preexisting ulceration as described by G. Hauser in 1926. However, recent investigation revealed the “wane and wax” of ulceration of early gastric cancer (malignant cycle-Murakami) during years of observation. The present study was attempted to disclose the nature of type Ⅲ cancer mainly from histopathological viewpoint.

　Of all 601 cases of early gastric cancer resected at our institution during the past 20 years, the Type-Ⅲ cancer was found in 88 cases (15 per cent). They showed cancer development only on the ridge of ulceration, and never in the bottom of excavation. Therefore “the excavated type” is pathologically not an appropriate expression for this group. When viewed from modes of cancer development around ulcers and histological characteristics of ulceration, these cases can be divided into two groups; in 23 out of 88 cases the concept of “malignant cycle” might be applied to the genesis of malignant ulceration, and accordingly a preceding mucosal cancer might have received peptic ulceration to form “Type-Ⅲ”; however, in the remaining 65 cases precedence of chronic peptic ulcer was most plausible for forming malignant alteration, and mucosal changes surrounding an ulcer (accompanying gastritis) seemed to be a possible site of carcinogenesis.

　Clinically it is claimed that the diagnosis of the Type-Ⅲ cancer can only be established by multiple biopsies since these malignant ulcers could not be differenciated from benign ulcers macroscopically.