炎症性腸疾患に合併する腸管腫瘍―潰瘍性大腸炎関連大腸癌の検討

Clinical and Endoscopic Features of Colorectal Cancer Associated with Ulcerative Colitis

潰瘍性大腸炎（UC）の長期経過例に癌合併率が高いことが知られており，定期的な内視鏡サーベイランスが必要である．しかし，炎症をもつ粘膜に発生するため，早期発見は容易ではない．したがって，欧米のガイドラインは多数の盲目的生検によるサーベイランスを推奨してきたが，有効性は得られていない．UCに合併する大腸癌およびdysplasiaの早期発見のためには，それらの内視鏡像の再検討を通じ，初期病変の特徴をよく理解する必要がある．サーベイランスの効率を高めるためには高危険群をセレクトし，色素内視鏡を併用した精密な内視鏡観察が求められている．癌・dysplasiaの早期発見への取り組みとともにさらに重要なことは，癌発生予防のための粘膜治癒を目標とした適切な内科治療である．

　It is well accepted that there is a high prevalence of CRC（colorectal cancer）in patients with long-term ulcerative colitis. Because CRC is an important and life-threatening complication associated with UC, endoscopic cancer surveillance is recommended. But it is difficult to detect early lesions originating from flat mucosa with active inflammation. Although practical guidelines of western countries recommend surveillance programs using random biopsy specimens, satisfactory results have not been obtained. It is essential for the early detection of UC-CRC（UC-associated CRC）to understand the characteristics of the endoscopic findings of those lesions. We emphasize that selection of high-risk-group members and careful examination using chromoendoscopy are essential to detect early lesions of UC-CRC. Furthermore, it is important, to reduce CRC risk and to have mucosal healing by adequate medical therapy as the treatment goal for UC.