噴門部胃癌（腺癌）の組織発生―幽門部癌との比較

Histogenesis of the Cardiac Carcinoma (Adenocarcinoma) in Comparison with that of the Antral Carcinoma

　食道胃境界領域癌のうち，癌の中心が食道胃接合線より2cm以内の胃に存在する腺癌（以後，噴門部胃癌）に注目し，その統計的ならびに組織学的特徴を述べ，さらに，癌の組織発生，特に分化型癌と腸上皮化生との関係について，幽門部の癌（腺癌）と比較しながら考察したい．

噴門部胃癌（腺癌）の特徴

　1955年から1974年の20年間に癌研病院において切除された胃癌のうち，最大径10mm以上の腺癌を有する症例は4,247例で，男が2,671例，女が1,576例である．前述のように噴門部を食道胃接合線より2cm以内と限定し，癌の占居部位を癌巣の中心部位で表わすと，噴門部癌は，男が2.8％，女が1.6％であり，男女とも胃癌全体の数％にすぎなかった（Table 1）．

　The cardiac carcinoma (microscopically, an adenocarcinoma), primarily arising from the portion 2 cm below the esophago-gastric junction, is rather rare in incidence. Of 2671 males and 1576 females with gastric carcinoma (microscopically, an adenocarcinoma) resected at the Cancer Institute Hospital, Tokyo, during a period of 20 years from 1955 to 1974, its incidences were 2.8% for male and 1.6% for female respectively. Histologically, the adenocarcinoma of gastric origin can be classified into two groups, either differentiated or undifferentiated. So far as the cardiac carcinoma was concerned, the ratios of differentiated type to undifferentiated one (DUR) were 2.3 : 1 in male and 1.3 : 1 in female. As to the antral carcinoma, on the other hand, its ratios were 1.5 : 1 for male and 0.8 : 1 for female. Conclusively, it can be admitted that the DUR of cardiac carcinoma was much higher than that of antral carcinoma, either in case of male or of female.

　As a rule, when the patients aged more elderly, the carcinomas become more differentiated in typing.

　As for age distribution of the cases examined, the incidence of patients over 60 years of age in the cases of cardiac carcinoma (52%) was more or less higher than that in the cases of antral carcinoma (48%) in male, but this situation was reversed in female; 32% in the former and 39% in the latter. The DUR of cardiac carcinoma in each older age-group (50 s, and over 70) of male, however, was usually higher than that of antral carcinoma. Hence, it is considered that the high DUR of cardiac carcinoma was not attributable to age distribution of the cases.

　The extent of intestinal metaplasia in the cardia was compared with that in the distal part (angle or antrum) of the stomach on the lesser curvature for 41 cases with total resection of stomach. Then, we confirmed that, in 24 cases (51%) the former change was minor than the latter; in 15 cases (37%), equal in extent; and in only 2 cases (12%) the former was stronger than the latter. From the histogenetical standpoint of view about the gastric carcinoma, there happened a discrepancy between the DUR of carcinoma and extent of the intestinal metaplasia in the cardia.

　Correlation of the histological type of carcinoma with the extent of intestinal metaplasia over the mucosa near the tumor was investigated for 127 cases of cardiac and 1861 cases of antral carcinoma. As indicated in the reports, there existed a strict correlation between the differentiated type and the extent of intestinal metaplasia, but not the case in the latter. Therefore, the occurrence of differentiated carcinoma without intestinal metaplasia seems to be rather prominent in the cardia as compared with that in the antrum.