表層拡大型胃癌の内視鏡診断―とくに表層拡大型早期胃癌について

Endoscopic Diagnosis of Superficial Spreading Type of Gastric Cancer: Especially on early gastric cancer of this variety

　表層拡大型早期胃癌（superficial spreading type of early gastric cancer，以下SSCと略す）は外科医にとってやっかいな存在である．術前にその拡大した癌病巣の全貌を的確にとらえることができないと，切除範囲の選択を誤り，揚合によっては切り足しを必要とすることとなり，またときによっては癌巣を完全に切除し得ていないという事態も出てくるからである．

　われわれの教室における昭和42年5月から47年3月までの5カ年間の早期胃癌切除例数は195例であるが，これらのうち，病理組織学的検索により確認した癌病巣の拡がりが5.0×5.0cmをこえる，いわゆるSSCの症例は39例で，早期胃癌の20.0％であった．すなわち早期胃癌のなかで5例に1例はSSCがあるということであり，この確率は決して低いものではない．しかるに従来は日常の内視鏡検査に際して，このようなことはあまり念頭におかれていなかったといってよいであろう．もちろん外科の立場としては，とくに病巣の噴門側境界については常に厳しく観察を行なってきたつもりであるが，これをSSCとして把握したことは少なく，またその全貌を的確にとらえ得たSSC症例も多くはない．

　Superficial spreading type of early gastric cancer calls for accurate determination of its extent prior to surgical intervention. We may err in our judgement to what extent a given stomach should be removed. Sometimes a part of cancer lesion may remain unexcised, or additional excision may become necessary later to remove the remaining malignant segment.

　For the past five years superficial spreading type of early gastric cancer has been encountered in our department in 39 out of 195 cases of resection for early gastric cancer. Twenty-percent incidence is not a small number. Endoscopic results show that exact determination of its entire aspects was not always easy. Of 23 such cases we have actually examined, we were able to grasp its whole picture in only less than half of cases. Even gross observation of the resected specimen failed to reveal its entire extent in one third of them. We feel that endoscopic reappraisal of this variety of gastric cancer is therefore needed.

　In protruding type the entire aspects were not so difficult to know, while depressed variety such as IIc posed difficulty in the interpretation of marginal changes. The spread of IIb was most difficult for us to determine. Retrospective analysis of our results show that success depends on how we are able to ‘read’ mucosal changes (rough or fine, or with edematous appearance), alteration of the color of the mucosal surface, be it discoloration or reddening, and other minute findings such as bleeding spots or erosions. These minute changes after all correspond with those that from an index at present for the diagnosis of IIb. Gloss inquiry into those details is deemed to be bound up with elucidation of supeficial spreading type in its whole aspects. We believe most effective procedures for this purpose would be regulation of not only intensity of illumination but also vision angle, with additional help of color spraying method. what is equally important, one should always bear in mind that the incidence of this variety is not negligible. Prominent changes should not detract the examiner from close observation around them. The segment praximal to the main lesion demands special attention.