内視鏡的食道粘膜切除後の局所再発

Local Recurrence of Esophageal Squamous Cell Carcinoma after Endoscopic Esophageal Mucosal Resection

要旨　内視鏡的食道粘膜切除手技はほぼ確立されたが，予後，局所再発などいまだ解決されずに残された問題も多い．自検例を再検討したところ36例65病変中，局所再発は2病変で，局所再発率は3.1％であった．いずれも深達度m2の0-Ⅱc＋Ⅱb型癌で，ヨード不染境界は一部不明瞭であった．1例は3か月後のヨード内視鏡検査で再発が確認され，他の1例は2か月後のヨード内視鏡検査では不染帯は認められず，7か月後のヨード内視鏡検査で初めて局所再発が認められた．局所再発の早期発見のため，3か月後のみならず，6か月後のヨード内視鏡再検が重要と思われた。1例は再粘膜切除で根治したが，他の1例は2年後の現在も局所再発を繰り返し，治療を継続している．いずれも粘膜切除終了時にヨード不染帯の取り残しはなかったが，局所再発を来した．ヨード染色後約1か月間は癌の一部が基底層型になり，ヨードに染色されるため，ヨード不染帯を完全に切除しても基底層型発育部を取り残す可能性が考えられた．したがって，最後のヨード染色から1か月以上の期間を置いてから粘膜切除を施行することが局所再発予防に重要と思われた．

　Endoscopic esophageal mucosal resection (EEMR) is an effective treatment for esophageal superficial cancer. The local recurrence rate of EEMR was 3.1% (two in 65 lesions) . The depth of invasion of the two local recurrent cases was m2. Macroscopically, they were 0-Ⅱc+Ⅱb type and the margin of the iodine unstained area was partially unclear. In one case, a local recurrence was found by chromoendoscopic examination three months after EEMR. In the other case, the two month post-EEMR follow-up examination did not disclose a local recurrence, but seven month examination did. For detecting a local recurrence at an early phase, endoscopic iodine staining should be performed both three and six months after EEMR.

　Both cases were treated by re-EEMR, but a “re-recurrence” was found in the second case, which was treated by laser irradiation. Margin of the iodine unstained lesion became unclear about one month after iodine spreading. So EEMR should be performed one month or later the last endscopic iodine staining.