多発胃癌の通常内視鏡診断―ESD施行例の検討

Multiple Early Gastric Cancers Resected using the Endoscopic Submucosal Dissection Method

要旨　2003年11月から2009年12月までの間にESDにて切除された初発早期胃癌症例725例を対象とし，以下の結果を得た．多発例の頻度は161例（22.2％）で，そのうち同時多発例は88例（12.1％），異時多発例は73例（10.1％）であった．性・年齢は，男：女＝3.1：1，平均年齢71.9歳であった．病変数は，同時多発例は，2重複が73.9％，3重複以上が26.1％，異時多発例は，2重複が64.4％，3重複以上が35.6％であった．部位は，同一領域ではM，L領域に，隣接領域ではML領域に多い結果であった．平均腫瘍径については，特に異時多発例の初回病変は17.6mm，異時性病変は13.7mmであり，これらの間に有意差を認めた．組織型では，多発例において低異型度分化型癌の割合が有意に高かった．深達度に関しては，異時多発73例のうち3例（4.1％）は異時性病変がSM2以深であった．異時性病変発見までの期間は，3年以内に85.7％が発見され，最長では5年2か月目に発見されていた．胃癌の内視鏡診断に当たっては，多発胃癌の特徴を踏まえた注意深い観察を行い，治療後少なくとも1年ごとの内視鏡検査が必要であり，治療後5年以内はもちろん，可能なかぎり長期間の追跡を行うことが重要である．

　We investgated seven hundreds and twenty five patients with early gastric cancer resected by ESD from 2003 to 2009. We extracted one hundred and sixty one patients（22.2％）with multiple early gastric cancers, and divided them into two groups : the patients with only synchronous lesions and the patients with metachronous lesions. The characteristics of multiple early gastric cancers are as follows :

　1）The number of the patients with only synchronous lesions were eighty eight（12.1％）, and that of the patients with metachronous lesions were seventy three（10.1％）.

　2）In the group of synchronous lesions, the rate of two-time lesions was 73.9％, and that of three-time or more was 26.1％. In the group of metachronous lesions, the rate of two-time lesions was 64.4％, and that of three-time or more was 35.6％.

　3）Concerning site of the lesions, multiple early gastric cancers are frequently detected in the M and L region.

　4）In the group with metachronous lesions, the mean size of the metachronous lesions（13.7mm）was significantly smaller than that of lesions at the time of first treatment（17.6mm）.

　5）The rate of low grade differentiated type was 21.1％ in the group with single early gastric cancers. Otherwise, the rate of low grade differentiated type was 37.5％ in the group with synchronous lesions, and 35.6％ in the group with metachronous lesions. There is a significant difference between single early gastric cancers and multiple early gastric cancers.

　6）In the group of metachronous lesions, the rate of the depth of invasion over SM2 was 4.1％.

　7）85.7％ of the patients with metachronous lesions were detected within three years. But, there have been cases detected after three years or more.

　In conclusion, we have to understand these characteristics of multiple early gastric cancers, and carefully diagnose them.