早期大腸癌内視鏡治療後のサーベイランス

Surveillance after Endoscopic Treatment of Early Colorectal Cancers

要旨●Japan Polyp Studyのデータから，早期大腸癌に対する内視鏡摘除後のIL発生頻度について検討した．1次TCSにてM癌を摘除した群では，1年後のIL（10mm以上の腺腫，高度異型腺腫，癌）発生率が6.8％と，M癌摘除歴なし群の2.3％と比べ，有意に高かった．2回のクリーンコロン化を行うことで，その後3年間に発生するM癌/浸潤癌の発生頻度は0.4％，0.05％と低下し，2度のTCSが大腸癌発生抑制により効果的に働くことが示唆された．また，SM浸潤癌に対する内視鏡治療単独例の再発リスクに関する検討を論文レビューから行った．4論文より1,312例のデータを集計した結果，再発例（3.4％）の約90％がリンパ節転移リスクを有し（HR群），HR群に限定すると再発率は6.8％と高く，転移リスクがなければ再発率は1％以下であった．

　We assessed the incidence of ILs（index lesions）following endoscopic removal of early colorectal cancer using data from the JPS（Japan Polyp Study）. In the patients' group who underwent treatment for intramucosal cancer at the baseline, TCS（total colonoscopy）had a significantly higher incidence of ILs（large adenoma≧10mm, high-grade adenoma, cancer polyp）after 1 year than patients' group who had no history of endoscopic removal of intramucosal cancer. Two times complete TCS, including polypectomy, decreased the incidence of intramucosal cancers（0.4%）and invasive cancer Therefore, we suppose that two times TCS is an effective procedure for prevention of colorectal cancer. Further, we reviewed 4 articles to assess the risk of recurrence after endoscopic treatment alone for submucosal invasive cancers. Data were collected and analyzed for a total of 1,312 patients with submucosal invasive cancer. The overall recurrence rate was 3.4% and approximately 90% of these cases were at a simultaneous risk of LNM（lymph node metastasis）. The incidence of recurrence after endoscopic removal in patients at risk of LNM was more than 6.8%. In contrast, the recurrence rate in patients without risk of LNM was less than 1%.