食道表在癌における拡大内視鏡によるT1b-SM2診断の現状と課題

Prediction of the Invasion Depth of SM2 Superficial Squamous Cell Carcinoma Based on a Magnifying Endoscopic Classification of the Japan Esophageal Society

要旨●食道学会分類のB3血管はSM2癌の指標として用いられているが，自験例ではB3血管のSM2癌に対する感度は25%と低かった．また，B3血管が病変内にみられれば病変の深達度はほぼSM2であるが，病変周囲の周堤部にみられる場合はSM1以浅にとどまることがあり，注意が必要である．B3血管の低い感度を補完する指標として“B2血管領域10mm以上”や“0-I隆起＋B2血管”があり，これらはSM2の診断感度を向上させるが，感度と特異度の両面で優れているかは今後の検討が必要である．また，拡大観察にEUSを加えることで新たな情報が加わるが，その上乗せ効果は隆起性の病変で大きい傾向にあった．

　Type-B3 vessel is a diagnostic criterion for cT1b-SM2 tumors in a magnifying endoscopic classification of the Japan Esophageal Society. The sensitivity of B3 vessels for pT1b-SM2 tumors was 25% based on the analysis conducted at our hospital. Although B3 vessels demonstrated pT1b-SM2 tumors, B3 vessels in SMT-like marginal elevation did not always correspond to pT1b-SM2 tumors. The diameter of B2 vessels can reach more than 10mm, and B2 vessels on 0-I protrusion can be considered as criterion for cT1b-SM2 tumors to supplement the low sensitivity of B3 vessels for pT1b-SM2 tumors. Although these criteria increase the sensitivity of diagnosis of cT1b-SM2 tumors, the sensitivity and specificity of cT1b-SM2 tumors diagnosis should be reviewed prospectively. EUS provides additional information along with conventional endoscopy and magnified endoscopy in the prediction of tumor invasion depth, especially in elevated esophageal cancers.