咽頭・食道癌の深達度診断における病理のevidence—病理学的深達度診断法と深達度によるリンパ節転移率について

Pathological Assessment and Diagnostic Challenges in Depth of Invasion for Pharyngeal and Esophageal Cancers：Current Evidence and Clinical Implications

要旨●悪性腫瘍の進行度はTNM分類によってなされるが，咽頭・食道を含む消化管の癌でのT分類は壁深達度によって決定される．咽頭は食道と異なり粘膜筋板を持たないため，筋層より表層の上皮下結合組織は粘膜下層の代わりに上皮下層と称し，腫瘍の厚さをもって深達度とする．食道癌取扱い規約では表在癌の深達度はT1a-EP，T1a-LPM，T1a-MM，T1b-SM1〜3に亜分類し，Barrett食道腺癌においては，筋板が二重化することを踏まえてT1aをT1a-SMM，T1a-LPM，T1a-DMMと亜分類する．後半には咽頭癌およびBarrett食道腺癌を含む食道癌の各深達度におけるリンパ節転移の頻度についていくつかの既報をレビューして紹介する．

　The TNM classification system is widely used to determine the stage of tumoral malignant progression. In gastrointestinal malignancies, such as pharyngeal and esophageal cancers, the T classification is based on the depth of wall invasion by the tumor. However, unlike the esophagus, the pharynx lacks a muscularis mucosae, meaning that the subepithelial connective tissue above the muscularis propria is considered as the subepithelial layer, rather than the submucosal layer. Furthermore, the depth of invasion is determined by tumor thickness. The Japanese Classification of Esophageal Cancer methodically divides the depth of invasion for superficial esophageal cancer（T1）into T1a-EP, T1a-LPM, T1a-MM, T1b-SM1, SM2, or SM3. However, considering the duplication of the muscularis mucosae in Barrett's esophageal adenocarcinoma, T1a is further divided into T1a-SMM, T1a-LPM, and T1a-DMM. This review discusses the frequency of lymph node metastasis at various depths of invasion in pharyngeal and esophageal cancers, including Barrett's esophageal adenocarcinoma, and provides a literature-based overview.