大腸癌のX線像による遡及的検討

Retrospective Radiographic Study of Colonic Carcinoma

　大腸癌の発見は近年増加の傾向にある．その理由はX線検査および内視鏡検査，特に内視鏡的ポリペクトミーの進歩により，10mm前後の隆起性病変の発見と切除が容易になされるようになったためと考えられる¹⁾²⁾．このように小さな隆起性病変の発見とその組織学的検索の増加に伴い，最近では有茎性の隆起性病変と無茎性の隆起性病変との質的な相違性，腺腫と癌との関係などのいわば大腸癌の生物学的特性についての研究発表が次第に増してきている．しかし，どのような病変から大腸癌になるのか，どのような病変を経て進行癌になるのかといった研究は，いまだ不十分でかつ不明の点が多い．

　われわれは国立がんセンターにて手術された大腸癌の患者について，過去の注腸検査歴を詳細に聴取し，X線学的に病変を逆追跡する方法すなわち遡及的検討を行っている．その結果現在までに6例の大腸癌につき，検討に値する過去のX線写真を入手しえた．そして病変を遡及的に検討した結果，大腸癌の経過について興味深い新知見を得たので報告する．

　With the recent discovery of many small polypoid lesions in the colon, there is increasing interest in studies on the biological characteristics of colonic carcinoma, such as the relation between adenoma and qualitative differences between pedunculated and sessile polypoid lesions. However, the types of lesions that develop into cancer of the colon and especially how they develop into advanced cancer have not been studied enough for all questions to be answered. We have collected and studied films of double contrast enema taken from patients who were operated on at the National Cancer Center Hospital in Tokyo. A retrospective radiographic study was made in 6 cases (4 cases of advanced cancer and 2 cases of early cancer) and the following findings were obtained.

　1. The initial X-ray film of the six cases showed flat and sessile elevated lesions ranging in size from 7 to 14 mm in diameter.

　2. In four of the six cases, an adenomatous area could be found within the same lesion indicating the malignant potential of the adenoma.

　3. The growth of the flat type of elevated lesion was relatively slow in two of the six cases. One of them was a 7 mm elevation in diameter which took 6 years and 2 months to develop into a 29 mm advanced cancer and the other one was a 13 mm elevation in diameter which took 5 years and 6 months to develop into an advanced cancer of 70 mm in diameter.

　4. It seemed that there were individual differences in the growth rate of flat and sessile type of elevated lesions. In one case a 10 mm lesion in diameter developed in 2 years into an advanced cancer and in another case in 2 years and a half. It took 4 years in one case and 4 years and 2 months in the other for the same size lesion to develop into early colonic cancer.

　These findings indicate that elevated lesions which have these characteristics, flat, sessile and around 10 mm in size, are very important in relation to malignancy or canceration.