Department of Surgical Pathology, Sapporo Kosei General Hospital, Sapporo, Japan.
Department of Gastrointestinal Oncology, Osaka Medical Center for Cancer and Cardiovascular Disease, Osaka, Japan.
Dig Endosc. 2017 Apr;29 Suppl 2:3-10. doi: 10.1111/den.12792.
Siewert's classification of adenocarcinoma of the esophagogastric junction (EGJ) classifies tumors anatomically for determining the appropriate surgical technique. According to this classification, a type II tumor, true carcinoma of the cardia, is defined as a cancer within 1 cm proximal to 2 cm distal of the EGJ. Histological analysis indicates that the cardiac gland is present with a high degree of frequency between 1-2 cm to the gastric side and 1-2 cm to the esophageal side of the EGJ, which means that this zone can be considered as neither the stomach nor the esophagus but rather as a third zone known as the 'EGJ zone'. It has been suggested that there are multiple causes for development of adenocarcinoma in the EGJ zone. The TNM Classification of Malignant Tumours 7th Edition considers EGJ adenocarcinoma (EGJAC) occurring in the EGJ zone to be a part of esophageal adenocarcinoma (EAC). However, recent studies have indicated that EGJAC behaves differently from EAC and gastric carcinoma. Barrett's esophagus is now considered an important factor in the etiology of EGJAC, but, as yet, no studies have elucidated the differences between cancer arising from short-segment Barrett's esophagus and cancer of the gastric cardia. Thus, there is currently no clinical relevance to subdivision of adenocarcinoma in the EGJ zone into above or below the EGJ line.
Siewert 对食管胃结合部（EGJ）腺癌的分类从解剖学上对肿瘤进行分类，以确定合适的手术技术。根据这一分类，II 型肿瘤，贲门真性癌，定义为 EGJ 近端 1cm 至远端 2cm 内的癌症。组织学分析表明，在 EGJ 胃侧 1-2cm 和食管侧 1-2cm 范围内高度存在贲门腺，这意味着该区域既不是胃也不是食管，而是被称为“EGJ 区”的第三区域。有人认为 EGJ 区腺癌的发生有多种原因。第 7 版《恶性肿瘤 TNM 分类》认为发生在 EGJ 区的 EGJ 腺癌（EGJAC）是食管腺癌（EAC）的一部分。然而，最近的研究表明，EGJAC 的行为不同于 EAC 和胃癌。巴雷特食管现在被认为是 EGJAC 病因学中的一个重要因素，但迄今为止，尚无研究阐明短节段巴雷特食管起源的癌症与贲门癌之间的差异。因此，目前将 EGJ 区腺癌分为 EGJ 线以上或以下没有临床意义。
