Barrett食道癌のリンパ節転移頻度と特徴─多施設共同研究の結果から

Incidence and Characteristics of the Metastasis in Adenocarcinoma in Barrett's Esophagus：a Multicenter Retrospective Study in a Japanese Population

要旨●Barrett食道癌のリンパ節転移リスクに関して，これまで本邦からは症例数の問題などからその報告はほとんどなく，内視鏡的切除後の追加治療の是非については各施設に委ねられているのが現状であった．今回多施設共同研究（EAST group）を行い，外科的あるいは内視鏡的切除された311例のBarrett食道表在癌を解析した．深達度SMM/LPM癌およびリスク因子〔病変径3cm以下，脈管侵襲，深層粘膜筋板（DMM）以深の低分化腺癌成分〕のないDMM癌においてリンパ節転移はみられず，SM癌ではリスク因子（病変径3cm以下，脈管侵襲，DMM以深の低分化腺癌成分）のないSM 500μmまでのBarrett食道癌においても転移頻度は0％であった．さらなる検討は必要であるが，現段階ではSM1の定義は胃癌と同様に500μmの浸潤距離が妥当と考え，深達度LPMまでの癌では内視鏡的切除後の追加治療は不要であり，DMM癌やSM1癌ではリスク因子を病理組織学的に十分検討したうえで追加治療を判断すべきである．

　Little is known about the specific risks of metastasis in adenocarcinoma in Barrett's esophagus in relation to invasion depth and other pathologic factors. We conducted a multicenter, retrospective study at 13 high-volume centers in Japan from January 2000 to October 2014 to elucidate the risk of metastasis of adenocarcinoma in Barrett's esophagus. A total of 311 patients（176 surgical resections and 135 endoscopic resections）were included. Metastasis was considered positive with either histological confirmation of the surgical specimen or clinical confirmation during follow-up. Metastasis was considered negative if no evidence of metastasis was detected either in the resected specimens and during the follow-up of patients treated surgically or during the follow-up of patients within 5 years of endoscopic resection. No metastasis was detected in patients with either SMM/LPM or DMM cancer without lymphovascular involvement and a poorly differentiated component（0/142 lesions）, in patients with cancer invading the submucosa（1-500μm）without lymphovascular involvement and a poorly differentiated component, and in patients with lesions smaller than 30mm（0/22 lesions）. Patients with mucosal and submucosal cancers（1-500μm invasion）without risk factors have a low risk of metastasis and may thus be good candidates for endoscopic resection.