早期大腸癌の深達度診断―内視鏡診断の立場から

Evaluation of the Depth of Early Colorectal Cancers by Endoscopy

要旨　当院で1986年1月から1994年3月の間に切除された早期大腸癌は632病変(m癌483，sm癌149)である．これらのうち，内視鏡写真が良好で深達度の見直し診断が可能であったsm癌82病変とm癌84病変を対象とし，m，sm₁，sm₂以上の鑑別診断に有用な内視鏡所見の評価を行った．検討に際しては臨床経験が1年から8年までの5人の内視鏡医が，19項目の内視鏡所見について診断し，得られた成績を推計学的手法を用いて解析した．632病変の検討では，表面型を除き腫瘍の大きさや占居部位からsm₂以上の癌を推測することは困難と思われた．内視鏡写真が良好な166病変の検討では，推計学的にsm₂以上の癌に有意な所見として，有茎性では易出血性，内視鏡的硬さおよび腫瘍の崩れが，無茎性隆起では易出血性，分葉の欠如，内視鏡的硬さ，腫瘍の崩れ，緊満感およびびらん・潰瘍の合併が，また表面型では内視鏡的硬さ，緊満感，白斑，面状不整型陥凹および空気変形が挙げられた．これらのうち，色調，易出血性，分葉の欠如および白斑は，評価が容易で深達度診断指標として有用な所見と考えられた．また腫瘍の崩れ，内視鏡的硬さ，びらん・潰瘍，緊満感，およびひだの集中などの所見は，的確に評価することは困難であり，評価の客観化などについて今後更に検討すべきと思われた．

　Six hundred and thirty two early cancers of the large bowel were resected in the National Cancer Center Hospital during January 1986 and March 1994. As there was no or little correlation between the size of the lesion and the degree of submucosal invasion, it was considered to be difficult to speculate about the depth of submucosal invasion from the lesion size alone. Colonoscopic mucosal findings of early colorectal cancers(82 submucosal cancers and 84 mucosal cancers whose endoscopic films were good for evaluation)were evaluated statistically from the aspect of the depth of invasion. With respect to mucosal findings, in pedunculated tumor, there was mucosal bleeding, stiffness and collapse. In semipedunculated and/or sessile tumor, there was mucosal bleeding, lack of lobulation, stiffness, collapse, expansiveness and eroded surface. In flat tumor, there was stiffness, expansiveness, white spot, irregular depression and air deformation. These properties were considered statistically as reliable findings indicating sm massive cancers. On the other hand, reddish color, mucosal bleeding, white spot and lack of lobulation were considered as important, easy-to-evaluate findings indicating sm massive cancers. Furthermore, collapse, stiffness, expansiveness and fold convergence were also important findings indicating sm massive cancers, but were not so easy to evaluate.

More analysis is needed concerning the relationship of these latter properties to sm massive cancer.