10mm未満の大腸早期癌の内視鏡的特徴

Endoscopic Features of Small Colon Cancers Smaller than 10 mm in Diameter

要旨　10mm未満の小大腸癌について，内視鏡所見を中心に検討した．（1）ポリペクトミー症例（5mm以上10mm未満）で12.1％（19/157）に癌があった．また，ca/ca＋ad（ca：癌，ad：腺腫）は19/140（13.6％）であった．Sp（semipedunculated）タイプのca/ca＋adは22.8％，P（pedunculated）タイプでは5.5％であった．ポリペクトミーが施行された癌（5mm以上10mm未満）19例中10例に，内視鏡的に，くびれ，切れ込み，陥凹などの形状異常があった．Spタイプで形状異常をもつ小ポリープ（5mm以上10mm未満）の約半数は癌であることが示唆された．（2）径4mm（Spタイプ）の微小癌が1例あった．（3）色調から癌・非癌の鑑別の可能性を見出すことはできなかった．

　Small colon cancers, smaller than 10 mm in diameter, were examined with respect to endoscopic findings. Out of 157 polypectomized cases (5-9 mm in diameter) 19 specimens proved to have cancer. The ratio of ca to ca ＋ ad (ca:cancer, ad:adenoma) was 13.6％ (19/140). When calculated for semipedunculated type of adenoma in a similar way, the ratio was 22.8％, and that for pedunculated type, 5.5％. Ten out of 19 polypectomized cases (5-9 mm in diameter) had such abnormal configurations as notching, constriction and concavity endoscopically.

　It was concluded that small semipedunculated polyps with abnormal configuration were cancers with probability higher than 50％. We could not calculate the probability of correctly differentiating cancer from benign polyp in this study.