胃癌EMR後の遺残・再発に対する治療―外科手術例の検討から

Treatment of Remnants and Recurrence after EMR on the Basis of Analysis of Gastrectomy Cases

要旨　EMR切除断端における癌遺残によって生じると思われるEMR術後の遺残・再発に焦点を絞って，それに対する追加治療について外科手術例の検討から考察した．今回のテーマであるEMR後の遺残・再発の問題は，EMR切除断端における安全域（またはsurgical margin）の問題と切除断端における癌遺残に起因する術後の遺残・再発のことである．したがって，EMR後の遺残・再発は，EMR後の経過観察による判定ではなく，EMR標本による総合的根治度によって，「胃癌取扱い規約」（第13版）による粘膜切除後の“組織学的断端所見がLM（－）でEAと判断された場合の術後再発を‘再発’”とし，EA以外の場合には癌の遺残が否定できないので“総合的根治度がEBまたはEC後の再発を‘遺残'”と定義するのが望ましい．根治的EMRは，確実に癌が治るという根治性が前提条件であり，ごくわずかでもそれが損なわれる恐れがあれば，いかにQOLの向上という利点がある低侵襲性治療であってもこれを選択すべきではない．EMR後の遺残・再発に対する治療においても同様であり，その治療後の総合評価はすべて根治度が“EA”または“A”でなければならない．

　We studied remnants and recurrence of cancer which analysis of gastrectomy cases showed to be due to residual cancer cells in the EMR stump.

　Remnants and recurrence after EMR raise the two problems described below. One concerns safety area of the EMR stump, or surgical margin. The other concerns post-EMR remnants and recurrence caused by residual cancer in the stump. Therefore, remnants and recurrence after EMR should be histologically judged not by follow-up study after EMR, but by whether or not the cancer could be expected to be radically cured by EMR. Based on the Japanese Classification of Gastric Carcinoma, the 13th edition, a case of recurrent tumor after EMR with its specimen showing LM (－) and EA should be defined as post-EMR recurrence of cancer. Histological findings of the EMR specimen showing other than EA cannot exclude the fast that the cancer has remained. Therefore, a case of recurrent tumor after EMR with its specimen showing EB or EC should be defined as a remnant of the cancer that was treated with EMR.

　Curative EMR stands on the precondition that a cancer is surely cured. When there is any risk that curability is not guaranteed, we should not choose EMR even though it is a minimally invasive treatment to improve QOL. Similarly, any treatment for remnants and recurrence of cancer after EMR should achieve a score of EA or A for curability.