超音波内視鏡による食道m3・sm癌の深達度・リンパ節転移・再発診断の精度

Accuracy of EUS for Estimating the Depth of Tumor Invasion and for Diagnosing Lymph Node Metastasis and Recurrence in Patients with m3 and sm Esophageal Carcinomas

要旨　食道癌根治手術を回避するために，m₃・sm癌に食道温存治療が選択される機会が増えているが，リンパ節転移診断や再発診断の成績，長期予後など解明しなければならない問題が多い．食道m₃・sm癌132例を対象とし，食道温存治療の臨床経過，EUSの深達度・リンパ節転移診断および再発診断における精度と役割について検討した．EUSは心血管拍動の影響を受けずに頸胸腹の3領域を検索できるため，CTやUSよりリンパ節描出能が高かった．EUSによる深達度正診率は86.4％，リンパ節転移の正診率は82％であった．リンパ節再発例は，いずれもEUSで診断されていた．CRT例は3年近く経過してから増大リンパ節が出現することが多く，EMR例より再発の診断時期が遅くなる傾向がみられた．治療方針にかかわる場合にはEUS-FNABを行うこともあるが，CRTを選択する際には，定期的かつ長期的にCT，US，EUSで経過観察することが重要である．再発をより早期に発見するためにはEUSが不可欠である．

　Esophagus-preserving therapy has been increasingly used to treat esophageal cancer invading the m₃ and sm, thereby avoiding radical surgery. However, many problems remain to be solved, including the diagnosis of lymph node metastasis and recurrence and the assessment of long-term outcomes. We studied 132 patients who had esophageal cancer with m₃ and sm invasion. Clinical course after esophagus-preserving therapy, and the accuracy and roles of EUS for diagnosing the depth of tumor invasion, lymph node metastasis, and recurrence were assessed. EUS can be used to examine the cervical, thoracic, and abdominal regions, without being affected by heat beats. Therefore, EUS can more clearly depict lymph nodes than CT or US. The accuracy of EUS was 86.4％ for estimating the depth of tumor invasion and 82％ for diagnosing lymph node metastasis. All cases of nodal recurrence were diagnosed by EUS. Among patients who received chemoradiotherapy, enlarged lymph nodes often appeared around 3 years after treatment, and recurrence was diagnosed slightly later than that in patients who underwent endoscopic mucosal resection. Endoscopic ultrasound-guided fine-needle aspiration biopsy was sometimes performed to determine the treatment policy. Patients who receive chemoradiotherapy should undergo regular long-term follow-up by CT, US, and EUS. EUS is essential for the earlier detection of recurrence.