完全摘除生検可能な大腸T1（SM）深部浸潤癌の術前診断―通常内視鏡

Preoperative Diagnosis of Complete Resection Possible Colon Deep Invasive Cancer: nvasion Depth Diagnosis of Early Stage Colon Cancer by Normal Endoscopy

要旨　早期大腸癌409病変（pM癌103病変，pSM癌306病変）を対象として，通常内視鏡観察によるpSM高度浸潤癌（1,000μm以深，1,500μm以深，2,000μm以深各々）の診断能（感度・特異度・陽性的中率・陰性的中率）について検討した．内視鏡所見はpSM浸潤距離と有意な関係にあり，検討に当たっては（1）病変周囲伸展不良の有無，（2）深い陥凹の有無，（3）緊満感，の3点を指標とした．A）感度，特異度を重視した診断には（3）緊満感の存在が最も重要であり，over surgeryを防ぐことを目的とするB）特異度，陽性的中率を重視した診断には，（2）深い陥凹の有無が最も重要という結果であった．診断に他の2所見を加えることにより，少しだけ診断能を向上させることができた．また，A）感度，特異度を重視した診断結果は満足いくものであったが，B）特異度，陽性的中率を重視した診断結果は，追加検査に回す症例の割合が高くなるというという欠点を有していた．今後，効率のよい治療法決定のためにはさらなる検討が必要である．

　We assessed the diagnostic performance of normal endoscopy for advance pSM invasive cancer with invasion depths of 1,000μm, 1,500μm, or 2,000μm using sensitivity, specificity, positive predictive value, and negative predictive value. The lesions examined included 103 of pM cancer, 306 of pSM cancer, and 403 of early colon cancer. Endoscopic findings were used to indicate any significant relationships of the invasion depth of pSM cancer with disease characteristics including（1）the presence or absence of perilesional extension failure,（2）the presence or absence of recessed deep, and（3）the presence or absence of a tense feeling. As a result, the most important findings were a tense feeling in the diagnosis with a sensitivity and specificity and recessed deep in the diagnosis with a specificity and a positive predictive value. Further, by the addition of 2 other diagnostic findings, it was possible to slightly improve the diagnostic accuracy. Satisfactory diagnostic results were achieved when focusing on A）sensitivity and specificity and B）the positive predictive value and specificity. It is accompanied with a problem proportion of cases to turn to the next inspection that becomes high. Further study is required to efficiently make a decision regarding appropriate therapy.