大腸早期癌のX線診断

Radiographic Diagnosis of Early Cancer of the Colon

　胃早期癌に対して，大腸早期癌という言葉も広く普及し，その報告例も多くなりつつある．これからも大きな興味の対象として展開してゆくものと考えられる．しかしまた一方では，大腸早期癌の定義をめぐって，あるいは診断法や治療法をめぐって，多少の混乱があるかとも考えられる．このような時期に，将来にそなえるために，現状を整理し，問題点を指摘することも意義のあることと思われる．そこで，自験例の大腸早期癌に対するX線診断の現状を分析検討し，その診断能，診断の限界あるいは問題点などに主眼を置いて報告を行いたい．さらに，そこからひき出される結果によって，大腸早期癌診断に対するX線診断の位置づけを考察し，最後に胃早期癌と対比した検討を加えたい．

　検討材料は45例45病変の自験例で，家族性大腸ポリポージスの癌化例は除いた．大腸早期癌の定義および分類は，胃早期癌のそれに準じた．X線検査法は，one stage methodによる二重造影法である．

　The capability and limitations of diagnosis in early cancer of the colon have been analyzed in this paper. The materials consisted of 45 cases (45 lesions): 33 lesions of Type I; 7 of IIa type; 4 of IIa+IIc type, and one lesion impossible to classify. Study of the depth of cancer invasion showed that 22 lesions were m and sm. Their size varied accordingly. Seven lesions were less than 1 cm in diameter; 24 were 1～2 cm, 9 were 2～3 cm, and the remaining 5 measured more than 3cm in diameter. Of 45 lesions 17 were carcinoma in adenoma and 5 were adenoma in carcinoma. Detection of early cancer of the colon by was possible in as high as 95.5 per cent. However, the rate of correct diagnosis for its nature was only 47.6 per cent. It is because peclunculated Type I, the most common early cancer of the colon, is most often carcinoma in adenoma, and it is impossible to differentiate it from benign polyp by x-ray. Accordingly, the pedunculated Type I is not an object of diagnosis for determining its nature; it is indicated for polypectomy, after it has been found out. The capability of the x-ray diagnosis is displayed to the best advantage in sessile Type I, IIa, and IIa+IIc Types. Its limitations for determining the nature of cancer could not be lowered to less than 1 cm in diameter.