5mm以下の大腸微小腺腫の診断と取り扱い―見つけ出しと取り扱い

Diagnosis and Treatment of Colorectal Adenoma 5 mm and Less in Size

要旨　5mm以下の大腸腺腫は内視鏡的に摘除された全腺腫数の69％を占め，大腸疾患の中で最も日常的な病変である．大腸腺腫の形態は表面隆起型を示すものが82％を占めるが，陥凹型の腺腫も多数存在することを忘れてはならない．5mm以下の早期癌は73.1％が腺腫成分を合併していた．内視鏡的に摘除された5mm以下の腫瘍病変のうち，早期癌の割合は0.1％と低い．この成績に基づいて考えると，5mm以下の大腸病変は日常診療における場合と大腸癌検診における場合とで分けて取り扱ったほうがよいと思われる．日常診療では5mm以下の腺腫と言えども，内視鏡的に摘除されたほうがよく，大腸癌検診では必ず摘除されなければならない病変とは考えなくてよいものと判断する．

　Adenoma 5 mm and less in size is the commonest lesion in endoscopic examination of the large intestine. It accounts for 69% of all colorectal adenomas excised by endoscopic procedures.

　Although 82% of colorectal adenomas 5 mm and less showed superficial elevated appearance on endoscopy, it should be noticed that depressed type adenoma is not an extremely rare neoplasm in the large intestine.

　Adenoma component was found in 73.1% of early colorectal cancers 5 mm and less in size.

　The rate of cancer was only 0.1% among epithelial tumours 5 mm and less excised on endoscopy. Endoscopic treatment of epithelial lesions 5 mm and less found in the outpatient clinic and in mass surveys of colorectal cancer should be decided separately on the base of this data. Although epithelial tumour 5 mm and less may be a negligible lesion in a mass survey, it should, nevertheless, be excised endoscopically in outpatient clinics.