治療成績からみた食道m3/sm癌の治療方針―外科治療の個別化：センチネルリンパ節理論の観点から

Clinical Significance of the Sentinel Lymph Node Concept in Individualized Surgical Treatment for Superficial Esophageal Cancer with a Depth of m3/sm1

要旨　食道m₃・sm癌では，cN0症例と言えども潜在的リンパ節転移の可能性が否定しえない．内視鏡的粘膜切除術（endoscopic mucosal resection ; EMR）や内視鏡的粘膜下層剝離術（endoscopic submucosal dissection ; ESD）で局所制御が可能な場合でも広範なリンパ節郭清を伴う根治術を施行することが原則とされてきた．われわれは，センチネルリンパ節（sentinel node ; SN）理論を応用して食道m₃/sm₁癌に対して個々の症例のリンパ流，また実際の微小転移の有無に応じた根治手術の個別化や集学的治療への応用に取り組んでいる．SNはリンパ節生検，限定的リンパ節郭清の標的となり，SN転移陰性例に対する内視鏡的治療や縮小手術の適応が将来可能になるものと考えられる．また，内視鏡的治療の結果，病理学的解析からリンパ節転移の危険があると判断された場合の重点的リンパ節郭清あるいは放射線治療の標的としてSNを利用できる可能性が期待される．

　Although the local control of superficial esophageal cancer with a depth of m₃/sm₁ is feasible by endoscopic treatments, the risk of occult lymph node metastasis can not be excluded. Therefore radical esophagectomy with extensive lymph node dissection has been the standard approach for m₃/sm₁ esophageal cancer with a potential risk of lymph node metastasis. The sentinel node (SN) concept has been a focus of attention in the field of surgical oncology as a predictor of the regional lymph node status in various solid tumors. Recently several studies supporting the validity of the SN concept in cT1N0 esophageal cancer have been reported. SN technology will enable us to carry out various clinical applications, including individualized application of additional treatments for m₃/sm₁ esophageal cancer locally resected by EMR/ESD, and selective lymphadenectomy or irradiation focused on the SN basin. Although there are several remaining technical issues, the SN concept would contribute to the establishment of an individualized multi-modal treatment for m₃/sm₁ esophageal cancer.