微小胃癌の生検

Biopsy under Direct Vision for Early Gastric Cancer Smaller than 1 cm in Diameter

はじめに

　現在のX線，内視鏡の進歩，これにともなう胃生検法の発達により，どの程度まで微細な病変を診断しうるかについては，しばしば問題にされてきた．中でもごく小さな胃癌，特にⅡb病変を発見することは，X線および胃内視鏡にたずさわる者のひとつの大きな目標である．しかし，一般に長径1cm以内の小胃癌の診断は，現在の優れた内視鏡，胃生検法を駆使してもなお至難である．幸いわれわれは現在までに16病変のこの微小胃癌を経験しており，これをもとに，この内視鏡診断，生検成績に検討を加え，このような微小病変に対する胃生検法の特徴，意義について述べてみたい．

　なお，われわれはlcm以内の微小胃癌を次のような基準のもとに検討した．

　1）病巣は原発性のもので，他の部位の癌転移を含めない．

　2）X線，内視鏡所見を検討する必要上，非癌部分をも含めた全病変の最大径が1cm以内のもの．

　3）病変の最大径は摘出生標本からの計測による．

　It is an important problem to what a degree can a minute lesion be detected by biopsy. In spite of efforts made in recent years in finding the smallest possible cancer lesion, the diagnosis of early gastric cancer less than 1 cm in diameter still harbors many difficulties.

　Of 16 cases of early gastric cancer less than 1cm in the longer diameter among 162 cases of early one recently encountered in the authors’ department, 11 were preoperatively diagnosed as such by x-ray and gastroscopic examinations, while the other 5 were concomintantly found at operations for other gastric diseases.

　There was no relationship between the accuracy of the diagnosis and the size of cancer lesion. Naturally, however, the smaller a cancer lesion is, the more diflicult the diagnosis. In 2 cases of IIb type early cancer, the longer diameter of the invaded area was less than 5mm and one of them was preoperatively diagnosed as such by endoscopy and biopsy. This fact clearly shows the possibility of diagnosing a very minute Ⅱb type early cancer.

　A most important diagnostic method of minute early gastric cancer, biopsy under direct vision must be done in a very cautious way in its first trial, because the rate of success in proving cancerous tissue in the intial (about 70%) would gradually go down less than 50% in the subsequent trials.

　The success of biopsy in demonstrating minute cancer depends on the dynamic observation of the gastric lumen with the amount of air in it as well as the tonus of the gastric wall in a most suitable state.