表在型食道胃接合部癌の外科的切除の実際と課題

Surgical Treatment for Superficial Esophagogastric Junction Cancer

要旨●食道胃接合部癌には，縦隔側と腹側の両方向のリンパ流が存在しているため，縦隔リンパ節と腹腔内リンパ節の双方を郭清する必要がある．本邦で行われた多施設共同後向き研究の結果をもとに作成されたアルゴリズムによると，胃側に中心を有する表在型食道胃接合部癌に対しては腹腔内リンパ節のみの郭清で十分とされる一方，食道側もしくは食道胃接合部直上に中心を有し，組織型が腺癌の場合は腹腔内リンパ節と下縦隔リンパ節，組織型が扁平上皮癌の場合はこれらに加えて中縦隔リンパ節の郭清も必要となる．現在，日本胃癌学会と日本食道学会合同による前向きの臨床試験を実施しており，より正確なデータに基づいた郭清範囲が決まるものと期待される．

　Esophagogastric junction cancer entails two directions of lymphatic flow toward the mediastinum and the abdomen ; therefore, both the mediastinal and abdominal lymph nodes should be dissected. The results of a multi-institutional retrospective study in Japan suggest an algorithm showing the fields of lymph node dissection for esophagogastric junction cancer as follows：abdominal nodes for superficial tumors with the center of the tumor located below the esophagogastric junction ; abdominal and lower mediastinal nodes for superficial adenocarcinoma with the center of the tumor located on or above the esophagogastric junction ; and abdominal and lower/middle mediastinal nodes for superficial squamous cell carcinoma. A multi-institutional prospective study is ongoing in Japan with the collaboration of the Japanese Gastric Cancer Association and the Japan Esophageal Society, which will lead to the establishment of the field of lymph node dissection based on more accurate data for patients with esophagogastric junction cancer.