除菌後発見胃癌診断におけるNBI観察の有用性

Efficacy of Narrow Band Imaging for Diagnosing Early Gastric Cancer after Helicobacter pylori Eradication

要旨●除菌後発見胃癌60症例の白色光・NBI拡大観察による境界診断能を比較した．また対象の中で胃角より口側に位置する43病変の背景粘膜を拡大内視鏡・病理組織像で検討した．境界診断正診率は白色光65.0%（39/60），NBI拡大観察98.3%（59/60）で，NBI拡大観察が有意に高かった．病変周囲の背景粘膜を拡大内視鏡で観察すると，病変の存在位置は中間帯：胃底腺領域：萎縮領域は19例（44.1%）：3例（7.0%）：21例（48.8%）と判定された．病理組織学的判定では胃底腺と幽門腺化生または腸上皮化生が混在し中間帯と判断される症例は31例（72.1%）であった．中間帯はまだらな色調と凹凸により病変の認識が困難となりやすいが，非・弱拡大NBIで範囲診断できることも多く，非拡大NBIによるスクリーニングが有用な可能性がある．

　We compared the diagnostic abilities of white light imaging and NBI（narrow-band imaging）for the lateral margin of 60 early gastric cancers detected after Helicobacter pylori eradication. Regarding the lesions located in the gastric angle, body and fornix（43 cases）, we investigated the mucosa surrounding the lesions by magnifying endoscopy and histology. The diagnostic accuracy of the lateral margin by white light imaging and NBI was 65% and 98.3%, respectively ; the latter was significantly higher than the former. In addition, magnifying endoscopy diagnosed the surrounding mucosa as atrophic area（21 cases, 48.8%）, fundic glands area（3 cases, 7.0%）, and intermediate zone（19 cases, 44.1%）. Histologically, the surrounding mucosa of 31 cases（72.1%）was determined as the intermediate zone, which exhibited the fundic glands and pyloric metaplasia and/or intestinal metaplasia. Often, the intermediate zone appears with uneven coloration and surface structure, which tend to restrict the recognition of lesions by white light imaging. In contrast, NBI without magnification or with slight magnification can readily detect and delineate the lesions, highlighting the potential utility of NBI screening without magnification.