発育経過からみた胃癌の自然史―癌組織型と発育進展様式について

The Natural History of Gastric Carcinoma Viewed from Prospective or Retrospective Follow-up Studies: in Relation to Histological Type and Growth Patterns

要旨　胃癌の自然史を知る目的で，過去10年間にprospective（一部retrospective）に経過観察可能であった胃癌32例（早期癌11例，進行癌21例）を対象に癌組織型と発育様式につき検討し，以下の結論を得た．（1）分化型腺癌の中で高分化，中分化型癌（tub₁，tub₂）14例のうち11例までが緩徐に発育進展を示す傾向にあり，早期癌から進行癌に進展する期間は平均5年2か月であった．しかし乳頭状腺癌（pap）3例の発育進展が速く，悪性度の高い癌と推測された．（2）未分化型腺癌15例（14例までが手術時進行癌）の発育経過をみると，①malignant cycleを繰り返しながら緩徐に進展するもの，②低分化腺癌でかつ充実胞巣型癌（solid type，medullary growth）．発育進展が速く，高頻度に肝転移を伴う，③Borrmann4型胃癌，と3つのタイプに大別される．（3）原発巣が指摘され，かつ経過追跡可能であったBorrmann4型胃癌9例における観察期間は平均20か月で，うち2例は32か月前，40か月前に胃生検で癌を確認した症例であった．Borrmann4型胃癌の経過は意外に長いことが判明し，終局的には胃底腺領域を中心としたⅡc型早期胃癌の発見が鍵となると断言できよう．

　In order to clarify the natural history of gastric carcinoma we made an analysis of prospective or retrospective follow-up cases in 32 gastric carcinoma patients (early: 11cases, advanced: 21cases), including Borrmann 4 type gastric carcinoma in 9 patients. In this paper the relation of cancer histology and growth patterns was mainly discussed and we came to the following conclusions: (1) 11 of 14 cases with differentiated carcinoma (tub₁, tub₂) showed slow growing patterns and the period from early cancer to advanced cancer was 4 to 6 years. Nevertheless, three cases showing papillary adenocarcinoma tended to progress rapidly within a short period of one or two years. These cases are considered to be high for biological malignancies. (2) Regarding the natural history of 15 undifferentiated adenocarcinoma patients, including one with early gastric cancer, we classified three types; ①slow growing type accompanied by malignant cycle even in advanced ulcerative cancer, ②rapidly growing carcinoma with solid and medullary pattern, very often leading to complications such as liver metastasis, and ③Borrmann 4 type. (3) As for Borrmann 4 type gastric carcinoma in our 9 cases, we pointed out the primary site by endoscopy, and the observation periods were 12-40 months (average 20 months). The focus of our diagnostic approach should be directed to early detection of Ⅱc-like lesions in the fundic gland area.