sm浸潤度細分類に基づく早期大腸癌のEUS深達度診断

Diagnosis of the Depth of Early Colorectal Cancer by Endoscopic Ultrasonography Based on the Subdivision of the Degree of Submucosal Infiltration

要旨　sm浸潤度細分類に基づくEUSの深達度診断能を評価するために早期大腸癌97例を対象に検討を行った．7.5MHz超音波内視鏡を用いた85例の成績は正診64.7％，誤診25.9％，描出不能9.4％であり，m，sm₁とsm_2,3の鑑別は描出可能であった77例中93.5％で可能であった．20MHz細径超音波プローブを用いた23例の成績は正診78.3％，誤診17.4％，描出不能4.3％であり，m，sm₁とsm_2,3の鑑別は描出可能であった22例中95.5％で可能であった．以上の結果から，早期大腸癌に対する内視鏡治療の適応を深達度のみから評価する場合にEUSは有用であると判断された．描出能では超音波プローブのほうが優れており，いずれかを選択するとすれば超音波プローブ単独でほとんど十分であると考えられる．

　We investigated the utility of endoscopic ultrasonography(EUS)for the diagnosis of the depth of early colorectal cancer based on the subdivision of the degree of submucosal infiltration in 97 cases. A 7.5 MHz echocolonoscope was used for 85 cases. The diagnosis was correct in 64.7% and incorrect in 25.9%; visualization of the lesion was inappropriate in 9.4%. The differentiation between m・m₁ and sm_2,3was possible in 93.5% of 77 cases in which visualization was appropriate. A 20MHz miniature ultrasonic probe was used in 23 cases. Diagnosis was correct in 78.3% and incorrect in 17.4%; visualization was inappropriate in 4.3%. The differentiation between m・sm₁and sm_2,3was possible in 95.5% of 22 cases in which visualization was appropriate. Accordingly, EUS was evaluated as useful in determining the indication for endoscopic therapy based on the degree of cancer infiltration. Our results suggested that a miniature ultrasonic probe is superior in the evaluation of early colorectal cancer.