内視鏡治療のみで経過観察可能な大腸sm癌の条件―臨床経過からの検証

Management of T1 Colorectal Cancer : Analysis of Cases with T1 Colorectal Cancer Treated by Endoscopic Mucosal Resection

要旨　教室におけるEMR施行症例を検証し，大腸sm癌のEMR後の治療方針につき検討した．対象184例のうち，リンパ節転移の有無を確認しえた98例中7例（7.1％）にリンパ節転移を認め，2例（1.1％）に異時性肝転移を認めた．sm1ではリンパ節転移はなく，sm浸潤が高度のものでリンパ節転移の危険性が高くなる傾向が認められた．その他のリンパ節転移の危険因子に関しては特徴的なものは見い出せなかったが，深達度sm1では脈管（リンパ管・静脈管）侵襲が陽性であっても，追加切除が不要である可能性が示唆された．一方，高度sm浸潤（sm2～3）症例に関しては，リンパ節郭清を伴う追加腸切除が必要と考えられた．追加腸切除の際には原則として全大腸を適応とした腹腔鏡下腸切除術を施行しており，良好な成績を得ている．

　This study was carried out to clarify the indications for endoscopic therapy for T1 colorectal cancers (CRC) by examining 184 patients who underwent endoscopic mucosal resection (EMR) in our department. The rate of lymph node metastasis was 3.8 ％ (7/184) and that of recurrence was 1.1 ％ (2/184). Specific risk factors to predict lymph node metastasis were not found in this study, but the degree of submucosal invasion tended to relate to the rate of lymph node metastasis. Patients with lymph node metastasis or recurrence were not found among those with only slight submucosal invasion (sm1), even if they suffered lymphatic or venous invasion. This result suggested that patients who have lymphatic or venous invasion may not need to undergo additional resection after EMR, as long as the degree of submucosal invasion is slight (sm1). On the other hand, patients who had CRC massively invading the submucosal layer (sm2～3) were recommended to undergo additional resection with lymph node dissection after EMR. Laparoscopic colorectal surgery has been performed with favorable results as an additional form of resection.

　1) Department of Surgery, Keio University School of Medicine, Tokyo