高分化型進行大腸癌の高・低異型度による生物学的悪性度の差について

Importance of Grading of Cytologic Atypia for Well Differentiated Adenocarcinoma of the Colo-rectum

要旨　高分化型進行大腸癌（916例）を細胞異型度から低異型度癌（面積が70％以上，24例）と高異型度癌（892例）に分類し，その組織学的予後因子を検討した．n（＋）は，それぞれ，11.1％と37.4％（p＜0.05），1y（＋）は7.1％と39.6％（p＜0.05），v（＋）は7.1％と75.0％（p＜0.01）であった．原発巣が低異型度癌のうち，転移巣の異型度が低異型度癌であったのは，n（＋）の1/2例（この1例では高異型度癌も転移），ly（＋）の0/1例，v（＋）の1/1例（高異型度癌も転移）であった．細胞異型度は高分化型大腸癌の悪性度判定に重要であるばかりでなく，大腸癌の組織診断基準や内視鏡的治療判定基準にも応用されるべきである．

　This study explores the difference in lymph node metastasis and vascular permeation between well differentiated adenocarcinomas with low-grade and high-grade atypia in the colo-rectum. The criteria for cytologic grading was originally proposed by Watanabe et al, 1988.

　The well differentiated adenocarcinomas, 916 tumors selected from 1,565 colo-rectal cancers as a total in our file, were grouped into low-grade cancer (24 tumors) and high-grade cancer (892 tumors). There was no significant difference in depth of invasion between them. Lymph node metastasis was significantly more common in high-grade cancer (37.4% vs 11.1%, p＜0.05). In order to detect lymphatic and venous permeation (with elastic fiber stein), step-wise sectioning was performed in 48 tumors with high-grade atypia and 14 ones with low-grade atypia. Lymphatic and venous permeation was significantly more common in the high-grade carcinoma than in the low-grade one, 39.6% versus 7.1% (p＜0.05) and75.0% versus7.1% (p＜0.01) respectively.

　These results indicate that the degree of cytologic atypia of well differentiated adenocarcinoma may provide a valuable information about biological behavior of colo-rectal cancer.