食道表在癌の深達度診断―通常観察の立場から

Endoscopic Estimation of Tumor Depth of Invasion of Superficial Esophageal Carcinoma

要旨　食道表在癌の通常内視鏡観察による深達度診断について，内視鏡的切除術（ER）例の150例と外科切除例の86例を対象に検討した．また，浅読み，深読み例を深達度亜分類別に内視鏡診断と病理組織診断について対比した．ER例，150例全体の正診例は126例で正診率は84％で，深達度亜分類別の正診率は，T1a-EP，LPM：91.0％，T1a-MM，SM1：73.8％，SM2：75.0％であった．外科切除例ではT1a-MM，SM1：86.9％，SM2，SM3：89％であった．診断を誤る主な要因としては（1）微小浸潤，（2）表層拡大病変，（3）病巣の再生上皮，（4）導管内浸潤，（5）上方発育病変，などが挙げられた．通常観察による深達度診断は簡便で有用な手段である．しかし，腫瘍表面性状の内視鏡所見のみで行う深達度診断は言うに及ばず，深達度診断そのものに限界があると思われた．

　We estimated the tumor depth of invasion of superficial esophageal carcinoma by conventional endoscopic observation.

　One hundred and fifty cases of endoscopic resection and 86 cases of surgical operation were enrolled in this study.

　The endoscopic depth of invasion and pathological diagnosis were compared.

　Concerning all the ER cases, the accuracy rates of endoscopic tumor depth of invasion was 84％ and the accuracy rate classified into three groups were as follows, T1a-EP, LPM : 91.0％, T1a-MM, SM1 : 73.8％ and SM2 : 75.0％. As for surgical operation cases the accuracy rate of T1a-MM, SM1 was 86.9％ and that of SM2, SM3was 89％.

　The main clinicopathological reasons for over or under-estimation were 1）minimal invasion 2）superficial spreading type lesion 3）covering by regenerated squamous epithelium 4）ductal invasion and 5）protruding type lesion.

　Estimation of tumor depth of invasion by conventional endoscopic examination is a simple and useful method.

　However, there is a limit to estimating the depth of invasion accurately by endoscopic findings reflecting only the characteristics of the tumor surface.