─早期胃癌の診断の基本─NBI拡大内視鏡診断:組織型診断の観点から

Diagnosis of Early Gastric Cancer Using Narrow-Band Imaging Magnifying Endoscopy：Perspectives from Tissue-Type Diagnosis

要旨●分化型癌（tub1，tub2，pap，胃底腺型胃癌/胃底腺粘膜型胃癌）そして未分化型癌（por/sig，muc）のNBI所見について概説し，早期胃癌の組織型診断におけるNBI拡大内視鏡の有用性を以下の項目で検討した．①優位な組織型の診断（分化型か未分化型か）の診断能は白色光92.9％：NBI 99.1％（104/112：111/112，p<0.05）でNBI拡大内視鏡が有用であった．②組織混在の状態（純粋分化型，分化型優位混在型，未分化型優位混在型，純粋未分化型）の診断能は，白色光83.9％：NBI 86.6％（94/112：97/112，p＝0.663）であった．③NBI拡大内視鏡の主たる組織型（tub1，tub2，pap，胃底腺型/胃底腺粘膜型胃癌，por/sig，muc）の診断能は86.6％（97/112）であった．NBI拡大内視鏡は優位な組織型の診断において有用であり，組織型の診断が概ね可能である．

　We investigated the capacity of NBI（narrow-band imaging）to detect differentiated cancers（tub1, tub2, pap, fundic gland-type gastric adenocarcinoma）and undifferentiated carcinomas（por/sig, muc）, as well as its usefulness in the histological diagnosis of early gastric cancer. The following findings were obtained：（1）the diagnostic abilities of white light and NBI for dominant tissue type（differentiated or undifferentiated）were 92.6% and 99.1% respectively（104/112：111/112, p<0.05） ; （2）the diagnostic abilities of white light and NBI for mixed tissue conditions（purely differentiated, mostly differentiated, mostly undifferentiated, and purely undifferentiated）were 83.9% and 86.6%, respectively（94/112：97/112, p<0.01） ; and（3）the diagnostic ability of NBI for the main tissue types（tub1, tub2, fundic gland-type, fundic gland mucosa-type, pap, por/sig, muc）, which are often targeted by this technique, was 86.6%（97/112）. Taken together, these results demonstrate the usefulness of NBI magnifying endoscopy for diagnosing the status of both dominant and mixed tissue types and that tissue-type diagnosis was generally possible.