早期大腸癌におけるX線学的および内視鏡学的深達度診断の研究

Radiographic and Endoscopic Diagnosis of the Depth of Invasion of Early Colorectal Cancer

要旨　大腸癌のうち粘膜内癌（m癌）と粘膜下層にわずかに浸潤した癌（sm₁癌）とは内視鏡治療（内視鏡摘除術）の対象とされ，粘膜下層に大量に浸潤した癌（sm₂およびsm₃癌）は外科的治療の適応と考えられている．われわれは，早期大腸癌119例（m癌31例，sm₁癌29例，sm₂癌24例，sm₃癌35例）を対象として，m癌，sm₁癌とsm₂，sm₃癌との鑑別がX線，内視鏡的に可能かどうか，smへの癌浸潤に起因すると考えられる病巣部の“伸展不良を現す所見”の有無を基準として検討した．IIa以外の肉眼型では内視鏡における"管腔の弧の硬化像"が最も有用な所見であった．また，X線検査では“画然とした硬化像”の有無が最も鑑別に有用であった．他の伸展不良所見も存在すればsm₂以上に癌が浸潤していた．病巣の伸展不良を現す所見以外，例えば緊満感などの所見は少なからず偽陽性，偽陰性が存在した．また，“伸展不良所見”の有無を的確に判定するためには，①十分な空気量を注入し，②腸管の蠕動運動の影響をなくした写真で判定し，X線検査では側面像の描出，内視鏡検査では遠見での観察が必要であった．

　The aim of the present study was the radiographic and endoscopic diagnosis of the depth of submucosal invasion in early colorectal cancer (mucosal and submucosal invasion). The depth of invasion was classified by histological examination as follows; A group (m and sm1 invasion) and B group (sm2, and sm3 invasion).

　The following four radiographic features (distinct rigidity of the colorectal wall, radiolucency around the tumor, mucosal convergence, central depression), and 10 endoscopic features (rigidity of an arc in the lumen, submucosal elevation around the tumor, mucosal convergence, ulcer or erosion, central depression, tense impression, redness, white spots, irregularity, disappearance of gloss) and tumor size were assessed and comparison was made between the A and B group.

　In the IIa type, the most significant feature was an impression of tenseness. But in other types of early colorectal cancer, the rigidity of an arc in the lumen was the most significant feature. It is concluded that the depth of cancer invasion, if divided into A and B group, will be able to be diagnosed endoscopically and radiographically.

　Technically, it is very important to obtain an adequate picture which can show the characteristics of regular features regularities. The lesion should be visualized with both an adequate volume of air and with control of perstalsis. It is important to visualize with a lateral view, radiographically, and with a distant view, endoscopically.