胃癌の時代的変遷―病理形態学の立場から

Changes in Pathological Observation of Gastric Carcinoma during 1961-1985

要旨　胃癌の罹患率は1963年以後減少している．この原因を究明するために，大阪府立成人病センターの外科手術例を用いて，手術時年齢50～59歳の症例を明治，大正，昭和生まれに分けて病理学的所見を検討した．明治，大正，昭和となるにつれて，有意に肉眼型では限局型が減少し浸潤型が増加し，組織型では分化型が減少し未分化型が増加し，腸上皮化生の高度なものは減少していた．以上の結果から，明治，大正，昭和となるにつれて，腸上皮化生が減少し，分化型癌の減少と相対的に未分化型癌が増加し，それを反映して肉眼型では限局型が減少し，相対的に浸潤型が増加したものと思われた．罹患率の低下は腸上皮化生の減少による可能性があると思われた．

　Statistics tell that the incidence of stomach cancer in Osaka has been declining for the these decades since 1963. To investigate the reason for this welcome trend, we analyzed the pathologic findings of the stomach cancers resected at The Center for Adult Diseases, Osaka, from patients between 50 and 59 years of age.

　In patients born after 1926, the ratio of intestinal metaplasia found in the mucosa surrounding cancer lesions, well differentiated carcinoma and localized carcinomas were less than those observed in patients born before 1926 (p＜0.01).

　We believe that the decline in the incidence of stomach cancers over these three decades is dependent mainly on the decline in the incidence of intestinal metaplasia of the gastric mucosa, which, in turn, leads to the decline in the incidence of well differentiated carcinomas and localized carcinomas.