5）超音波内視鏡

EUS Diagnosis of the Depth of Superficial Esophageal Cancer Invasion

要旨　食道癌の深達度診断を行うに当たり，各機器の精度は深達度により異なる．T1a-EP，LPMなどの浅い病変は，拡大内視鏡，NBIが有用であるのに対して，EUSは表面からでは判定が難しいT1a-MM，T1bに対して有用である．この際，粘膜筋板を指標として診断する．細径プローブによる深達度診断の正診率はT1a-EP，LPMは81％，T1a-MM，SM1は60％，SM2，3は87％であった．EUSにて癌巣が厚く広いもの，第6層（固有筋層）と腫瘍の間に境界エコーがないものは，外科手術の適応と考える．

　The selection of instruments for accurate diagnosis of the depth of superficial esophageal cancer invasion depends on the depth of cancer invasion.

　If cancer invasion is the superficial type, 0-IIa or 0-IIb, magnifying endoscopy or NBI enable more precise diagnosis. However, if the tumor is large or stiff or has few vessels, it is difficult to determine depth of invasion from the surface of the tumor. The depth of such tumors should be diagnosed by EUS.

　The accuracy attained by EUS was 81％ for T1a-EP and LPM. It was 60％ for T1a-MM and SM1 and 87％ for SM2,3. EUS should be selected in cases of T1a-MM and T1b, because it might give us important information for selecting treatment.