食道癌スクリーニングにおけるX線の役割

The Screening for Cancer of the Esophagus from the Viewpoint of X-ray Diagnosis

要旨　当センターにおける食道癌切除例の経験から，食道癌スクリーニングにおけるX線の役割を検討した．1982年までの食道癌切除例1,015例のうち，他施設を含めてX線検査でチェックできなかったものは17例（1.5％）で，大部分が表在平坦型もしくは表在陥凹型であった．X線スクリーニングに当たって，①胃検査のついでに食道を撮っておくという安易な気持を捨てる，②透視観察をおろそかにしないこと，③二重造影像を必ず撮る，特にhigh risk groupで良好な像が得られないときは経鼻挿管を行うこと，④読影力を向上させること，⑤納得できない所見はかすかなものでも精検，内視鏡検査を行うこと，以上の点が遵守されれば，食道癌のスクリーニングとしてX線は十分にその役割を果たしうると考えられた．

　Of the 1,105 cases of cancer of the esophagus resected in the Institute of Gastroenterology, Tokyo Women's Medical College up to 1982, superficial cancer cases including 46 (4.1％) of early cancer of the esophagus were 74 (6.7％). Among those cases there were 12 (1％ of total esophageal cancers operated upon) which were left unnoticed by x-ray examination in other nstitutions. According to the classification of x-ray diagnosis, most of the cases were of superficial flat-type and minute or very shallow superficial depressed ones. At the author's institution, five cases were not discovered during the initial x-ray examination and which were superficial flat-type cancers accompanied by varices and hiatal hernia of the esophagus, and a small (0.7 cm in diameter) superficial depressed-type cancer accompanied by gastric cancer, etc. Most of the cases which were difficult to be noticed by x-ray screening were of superficial flat-type, namely cancers in situ or with submucosal involvement. However, double contrast study made it possible to find a great part of them.

　The following points must be observed in performing screening by x-ray.

　1. Refrain from having an easygoing attitude such as taking x-ray pictures during the examination of the stomach merely by chance.

　2. Not to neglect the fluoroscopic observation because it is easy to detect slight changes through the flow of barium.

　3. To take double contrast pictures without fail. Especially in the cases of high risk groups it is necessary to introduce air through the nasal tube for better photography.

　4. Reading ability of the observer must be improved. Even when the lesion is indicated, there are cases when the observer misses it.

　5. To conduct close x-ray or endoscopic examinations for questionable findings even if they are small.

　When above-mentioned conditions are kept in mind, x-ray examination will surely be able to play its role sufficiently for screening for cancer of the esophagus.