細径パンエンドスコープによる胃癌の診断限界―特に経過観察による分析

Assessment of Small Diameter Panendoscopy for Diagnosis of Gastric Cancer: Comparative Study with Follow-up Survey Data

要旨　（1）細径パンエンドスコープ検査により胃癌なしとされたものの中から，その後の経過検査で発見された胃癌は，早期癌では噴門・大彎に少なく，進行癌では噴門・大彎に多かった．経過検査で発見された胃癌の初回内視鏡フィルムをretrospectiveに検討すると噴門・大彎に現れた進行癌は発見までの期間が3年以内と短いものが多く，初回検査でも同じ部位に所見の見られないものが多かった．これらの進行癌は早期癌として発見しにくいだけでなく比較的急速に発育・進展したものと考えられた．また，経過検査で発見された早期癌は期間の長短にかかわらず形態変化に乏しいものが多く，臨床からみて早期胃癌の中には発育・進展の遅いものがあることが推測された．（2）50歳以上の健康人男女9,499人（男5,258人，女4,241人）に細径パンエンドスコープによる胃の検査を行い，男性2.01％（106例），女性0.83％（35例），計1.48％（141例）の胃癌が発見された．その後胃癌なしとされた9,358人の追跡調査を行い，新たに男性19例，女性7例の胃癌が発見された．これらの結果より，細径パンエンドスコープの初回検査時の胃癌の見逃し率は少なくとも7.2％，50歳以上の胃癌の有病率は少なくとも男2.38％，女0.99％と推定された．

　We detected 57 gastric cancers during the follow-up survey out of 48,570 cases which had been initially diagnosed as non-cancerous by small diameter panendoscopy. The small diameter panendoscopic images of these cases were reviewed carefully.

　We classified them into the following groups; (A) cases in which sites of lesions were not included in the initial panendoscopic images, (B) cases without any distinct abnormalities perceived in the initial images, (C) cases in which lesions were overlooked in the initial panendoscopic examination. Twenty one cases (36.8%) belonged to Group (C).

　It was often the case that we detected advanced cancer at the cardia and along the greater curvature. On the other hand, we found early cancer occurred less frequently at the above mentioned regions. It can be assumed that these lesions were apt to be overlooked because of their locations being difficult to detect.

　Advanced cancer in these lesions seems to have grown rapidly because the initial panendoscopic images did not reveal any abnormality.

　Many early cancer cases showed only slight morphological changes. This suggests that some early cancer lesions grow slowly.

　We also investigated 9,449 people at the age of 50 years or older. There people had been diagnosed to be noncancerous panendoscopically by either follow-up examination or questionaire. This surveillance study revealed that at least 7.2％ of all the cancer cases detected finally were misdiagnosed by the initial panendoscopic examination.

　The morbidity rate of gastric cancer at the age of so years or older was at least 2.38％ in males and 0.99％ in females.