完全摘除生検可能な大腸T1（SM）深部浸潤癌の術前診断―注腸X線造影

The Usefulness of Barium Enema Examination for the Diagnosis of T1b Colorectal Cancer

要旨　FPD（flat panel detector）を用いた注腸X線造影検査による大腸T1癌の壁深達度診断について，伸展不良所見を指標としてその診断精度を検討した．さらに，完全摘除生検可能な大腸T1癌の術前診断について考察した．隆起型T1癌50病変のうち，伸展不良所見陽性25病変の平均垂直浸潤距離は3,897.8±1,300.3μm，表面型T1癌33病変のうち，伸展不良所見陽性18病変の平均垂直浸潤距離は2,169.4±713.3μmだった．T1b癌を診断する指標としての伸展不良所見の診断精度は，隆起型病変において感度は73.5％，特異度は100％，表面型病変において感度は73.9％，特異度は90.0％であり，従来の報告同様に特異度の高い所見だった．伸展不良所見は粘膜下層にしっかりとした癌塊が存在することに基づく所見であり，伸展不良所見を認める症例に対する内視鏡的摘除は慎重に対応すべきである．

　The present study evaluated diagnostic accuracy of findings of impaired pliability as an indicator for diagnosing the depth of invasion by T1 colorectal cancer according to barium enema examination using a flat-panel detector. We also discuss preoperative diagnosis of T1 colorectal cancer, for which a biopsy and complete resection are feasible. In cases positive for impaired pliability among elevated T1 lesions（25/50）and superficial lesions（18/33）, the mean（±SD）invasion depth was 3897.8±1300.3μm and 2169.4±713.3μm, respectively. For findings of impaired pliability as a diagnostic indicator of T1b cancer, diagnostic accuracy（sensitivity/specificity）was as follows: elevated lesions, 73.5%/100% ; and superficial lesions, 73.9%/90.0%. These data demonstrate high specificity, consistent with previous reports. Findings of impaired pliability are the result of the presence of a pronounced tumor mass in the submucosa. Careful endoscopic resection should be performed in such cases.