表面型大腸腫瘍の経過観察

Follow-up Examination of Colo-rectal Superficial Neoplasms

要旨　1980年1月より1992年10月までの聞に大腸腫瘍の内視鏡的切除を行い，その後，経過観察された337例について検討した．また，その期間に診断された表面型大腸腫瘍192病変の合併病変と，そのルーチンX線検査の描出能について検討し，次のような結論を得た．①初回病変が単発であっても，多発であっても経過中に癌を見つける率は変わらなかった．また，腺腫例と早期癌を含む例を比較しても変わらなかった．②経過観察中に見つかった癌は，右側結腸に多かった．③内視鏡検査の見逃し率は，5mm以下で27.4％，6～10mmで12.5％であり，上行結腸，直腸，S状結腸で高かった．④表面型大腸腫瘍のルーチンX線描出能は，5mm以下のⅡa，Ⅱa様腺腫で60％，Ⅱa＋Ⅱc，Ⅱa＋Ⅱc様腺腫，Ⅱc，Ⅱc様腺腫（Ⅱc＋Ⅱa，Ⅱc＋Ⅱa様腺腫を含む）で46％であった．また，内視鏡検査で見逃された21病変のうち9病変が描出されていた．⑤Ⅱa，Ⅱa様腺腫は，隆起型腺腫，隆起型早期癌との合併が多く，17病変の表面型腫瘍が合併していた．また，進行癌との合併が5例にみられた．Ⅱa＋Ⅱc，Ⅱa＋Ⅱc様腺腫でも，11病変の表面型腫瘍の合併をみた．しかし，Ⅱc，Ⅱc様腺腫（Ⅱc＋Ⅱa，Ⅱc＋Ⅱa様腺腫を含む）では，隆起型腺腫との合併は少なく，表面型腫瘍との合併はなかった．以上より，表面型大腸腫瘍は，同時性にも，異時性にも多発するものが多く，経過観察では見逃し病変の拾い上げが重要である．

　The results of follow-up examination given to 337 cases to which endoscopic mucosal resection was performed in the period from January 1980 to October 1992 were studied, especially on neoplasms grown after the endoscopic resection. And, co-existent lesion of 192 superficial colo-rectal tumors and demonstrability of these lesions of routine x-ray examination done in the same period were also analyzed. Results of this study are as follows:

　(1) Detectability of cancer is almost the same in the follow-up period in spite of the numbers of formerly resected lesion, single or multiple, and of the pathological diagnosis, cancer or adenoma.

　(2) Most of the carcinoma were found in the rightsided colon by follow-up examination.

　(3) False-negative rates of endoscopic examination are 27.4% for the lesions smaller than 5 mm in diameter and 12.5% for 5～10 mm lesions. False-negative rate is high, around 30%, and is decreasing in number in order of the ascending colon, rectum and sigmoid colon.

　(4) Demonstrability of routine x-ray examination for colo-rectal superficial neoplasms are 60% for Ⅱa and Ⅱa-like adenoma smaller than 5 mm, and 47% for Ⅱa+Ⅱc, Ⅱa+Ⅱc-like adenoma, Ⅱc and Ⅱc-like tumors including Ⅱc+Ⅱa early cancer and Ⅱc+Ⅱa-like adenoma. Nine lesions out of 21 lesions that were endoscopically overlooked were demonstrated by routine x-ray examlnahon.

　(5) In almost all cases with Ⅱa and/or Ⅱa-like adenoma, the other simultaneously co-existent elevated lesion or lesions such as elevated type of adenoma and/or Ⅱa type of early carcinoma were found. In the 112 cases, 17 superficial type of tumor were detected. Even 5 advanced cancer cases were newly found, also, in the 112 cases. In the 39 cases with Ⅱa+Ⅱc early carcinoma and/or Ⅱa+Ⅱc-like adenoma, co-existent 11 superficial type of tumor were detected. In the case with Ⅱc cancer and/or Ⅱc-like adenoma including Ⅱc+Ⅱa and Ⅱc+Ⅱa-like adenoma, however, the number of coexisting elevated type of adenoma is small in number and no superficial tumor was found.

　Based on the results mentioned above, the authors came to the conclusion as bellow: In almost all of the cases, colo-rectal superficial tumor may occur multiply, either simultaneously or metachronously. It is veryimportant to demonstrate and diagnose such a lesion or lesions as overlooked lesion or lesions, so to speak, with follow-up examination.