摘除法からみたLSTの中・長期経過─EMR/EPMR vs. ESD

Medium- and Long-term Follow up Data of Laterally Spreading Tumors after Endoscopic Resection : EMR/EPMR vs. ESD

要旨●側方発育型腫瘍（laterally spreading tumor ; LST）は4つに亜分類され，各々臨床病理学的特徴が異なる．亜分類の判別や色素拡大内視鏡観察などで正確な深達度診断を行うことと，適切な摘除法を選択することは表裏一体の関係である．当院で行ったLSTの治療結果より，亜分類別の特徴，部位別の特徴，EMRとESDの治療成績の比較，遺残再発後の経過に関して検討を行った．LST-G（H）は腫瘍径が大きくなってもほとんどSM浸潤を来さないのに対し，LST-NG（PD）は小さい段階より高率にSM浸潤を来す．EMR/EPMR後の遺残再発は，腸管の解剖学的な複雑さと大きな腫瘍径のため，盲腸，直腸の順で高い傾向となった．また，ESD群では有意に一括切除率が高く，遺残再発率が低かった．EMR/EPMR後の遺残再発の大部分は治療後初回の内視鏡検査で発見され，内視鏡での追加治療でコントロール可能であることが示唆された．内視鏡治療後の遠隔転移に関して，EMR/EPMRとESDの間に有意差は認めなかった．

　LSTs（laterally spreading tumors）are classified into four subtypes. These subtypes differ from each other in clinicopathological features. Judging the subtype and accurately diagnosing the invasion depth using magnifying endoscopy are inextricably associated with the selection of the adequate treatment method. We examined the characteristics and location of the subtypes of LSTs. In addition, we evaluated the outcomes of EMR（endoscopic mucosal resection）and ESD（endoscopic submucosal dissection）and recurrence. The submucosal invasive rate in LST-G（H）was very low even when they were large in diameter ; however, that in LST-NG（PD）was high even when they were small in diameter. The recurrence rate after EMR/EPMR（endoscopic piecemeal mucosal resection）was higher at the cecum and rectum, in that order, because of the anatomical complexity and larger tumor size. The en bloc resection rate was higher, and the recurrence rate was significantly lower after ESD than after EMR/EPMR. Almost all recurrences were diagnosed at the first endoscopic examination after EMR/EPMR, and it was suggested that the recurrence could be controlled with additional endoscopic therapy. There was no significant difference in distal metastasis between the clinical outcomes of EMR/EPMR and ESD.