大腸sm癌内視鏡切除後の再発・転移様式からみた早期発見のためのフォローアップ法

Long-Term Result and Condition of Recurrence after Resection of Minimally Invasive Colorectal Carcinoma

要旨　内視鏡切除を行い，1年以内に外科的追加切除せず経過観察したsm癌93例（sm浸潤が300μmまでのsm1が62例，sm2以深が31例）を検討した．sm1癌では62例中61例では再発を認めなかった．1例で局所再発を認めたが，見直し診断ではsm2癌に変更となった．sm2以深の癌では31例中6例19.4％で再発を認め，全体では93例中7例7.5％（局所再発6例，リンパ節再発5例，肝転移2例）に再発を認めた．再発の危険因子は，切除断端陰性もしくは不明，脈管侵襲陽性，中分化型腺癌ならびに滴状浸潤であった．再発確認までの期間は16～132か月で，1～6か月直前の検査から急速に発育するものがあった．内視鏡所見上は瘢痕部の変形の増強があり，超音波内視鏡検査およびCT検査では，腸管壁の壁肥厚所見が認められ，3例でEUSが診断の端緒となった．1例でPETが有用であり，サーベイランス時には粘膜下および腸管外の再発に留意する必要がある．

　93 cases of minimally invasive carcinoma removed by endoscopy were investigated. In 62 cases of sm1, which invaded within 300μm from the musucularis mucosa, one developed local recurrence. Of 31 cases, invading more than 300μm,6 cases (19.4 ％) showed recurrence, 5 local recurrence and 2 liver metastasis. In all, 7 (7.5 ％) of 93 cases suffered recurrence. Risk factors for recurrence were, positive for cut end and vascular invasion, element of moderatelly-differentiated adenocarcinoma and droplet infiltration. The period up to confirmation of the recurrence ranged from 16 to 132 months. In 2 cases, local recurrence was recognized early within 1～6 months after the previous endoscopic examination. This was recognized by the finding of deformity and rigidity of the removed site. Thickness of the colonic wall was also a sign, and endoscopic ultrasonography (EUS) was effective for diagnosing any submucosal element. FDG-PET was also useful for detecting recurrent tumor. We should pay attention to the submucosal or parenteral recurrence at the time of the surveillance.

　1) Department of Internal Medicine, Tokyo Metropolitan Komagome Hospital, Tokyo

　2) Department of Surgical Pathology, Kyoto Prefectural University of Medicine, Kyoto, Japan