表在型Barrett食道癌の転移・再発危険因子─第72回食道色素研究会多施設アンケート調査から

Pathological Risk Factors for the Recurrence or Metastasis of Superficial Barrett's Carcinoma

要旨●表在型Barrett食道癌は治療方針を決定する際，転移・再発の危険因子の把握が重要である．本稿では欧米の文献の評価と食道色素研究会で行った多施設アンケート調査の結果を合わせ，転移・再発の危険因子について記述した．欧米の文献では，腫瘍径20mm以内で，pT1a癌，高・中分化型腺癌で脈管侵襲のないものが“low risk”とされる．今回の集計結果ではさらに，浸潤様式INFc，また肉眼型0-I型はリンパ節転移の危険性が高かった．pT1b癌は，取扱い規約のSM1までで“low-risk”の症例は，内視鏡治療で根治可能と考えられた．今回の集計結果でリンパ管侵襲や再発の有無に差があることから，SM1の深さは500μmまでが適当と考えられた．

　Endoscopic therapy is often used for superficial Barrett's carcinoma（BC）. However, there is an urgent need to clarify the risk factors possibly involved in recurrence or metastasis. In this report, we address a range of potential risk factors on the basis of clinicopathological reports from Western countries and discuss the results of a questionnaire survey conducted by us.

　For Western populations, the criteria for“low-risk”superficial BC include a tumor size of ≦20mm, an intramucosal location, a well-to-moderately differentiated histology, and absence of lymphovascular invasion. Our data were mostly concordant with these risk factors.

　Many existing reports have indicated that submucosal cancers invasive to the superficial submucosal layer are curable if no risk factors other than depth are evident. Our present data indicated that many submucosal cases had no risk factors and were completely curable. As a benchmark for classification into“SM1”and“SM2”, 500μm is considered to be more suitable than 200μm.