臓器別からみた形態診断学―食道

Recent Advances in Diagnosis of Superficial Esophageal Cancer

要旨　内視鏡とヨード染色によるスクリーニング検査法の確立は，食道粘膜癌の診断を実現，その大部分がEMRにより根治が可能となった．EMRの適応がm1，m2であるため粘膜癌の深達度に関する精密診断が必要となった．新肉眼病型分類は粘膜下層癌と粘膜癌の鑑別を容易にし，深達度亜分類が病態研究の利便性を高めた．更にトルイジンブルー・ヨードニ重染色法やEUS（20MHz）の機器の開発が診断精度を向上させ，上皮内癌の診断精度は83％，粘膜固有層癌94％，粘膜下層癌88％と進歩を示した．X線診断はスクリーニングならびに精密診断の主役を内視鏡に譲り渡したが，近年復活しつつある．特にm3，sm1癌の精密診断における有効性が期待されている．この領域においては，画像診断，病理，治療，病態の理解などが良好な関係を保ち，顕著な進歩を遂げた．引き続きこの方向を進み更なる進歩が期待できると考えられる．

　Remarkable advances in clinical and pathological evaluation of superficial esophageal cancer have been achieved in the last thirty years in Japan. Upper gastrointestinal endoscopy aided by iodine staining made possible the surveillance of esophageal cancer and many patients with mucosal cancer have been detected. Because of the frequent occurrence of mucosal cancers of the esophagus clinical and pathological estimation of them improved significantly and resulted in treatment by endoscopic mucosal resection (EMR) in 1989. The clinical result of EMR for mucosal cancer was excellent and was accepted as the alternative to the radical esophagectomy. The gross classification of superficial esophageal cancer facilitated the differentiation of mucosal cancer from submucosal cancer. The subclassification of the depth of cancer invasion and developments in endoscopic ultrasonography (EUS) using 20 MHz also encouraged further research on superficial esophageal cancer. Esophagography had not been an important measure in either early detection or clinical estimation of mucosal cancer of the esophagus, but, recently, x-ray study has become recognized as a reliable means for the clinical estimation of m3 and sm1 esophageal cancers. EUS has played a leading role in the clinical estimation of lymph node metastasis.