The Siewert-Stein classification of esophageal adenocarcinoma classes tumors of the gastro-esophageal junction according to the relationship between the epicenter of the tumor and the gastro-esophageal junction 1. The classification system was initially proposed by Siewert et al in 1996, becoming widely used in predicting lymph node spread and directing optimal management 1.
Classification
type I: adenocarcinoma of the distal esophagus (epicenter of lesion 1-5 cm above gastro-esophageal junction)
type II: adenocarcinoma of the cardia (epicenter of lesion up to 1 cm above or 2 cm below gastro-esophageal junction)
type III: sub-cardial type adenocarcinoma (epicenter of lesion 2-5 cm below gastro-esophageal junction)
Type III adenocarcinomas generally have a worse prognosis 3.
Staging
As of the 8th edition of the AJCC Cancer Staging Manual, tumors with an epicenter <2cm into the gastric cardia and involving the gastro-esophageal junction (type I and type II) are staged as oseophageal adenocarcinoma 4. Conversely, tumors with an epicenter located >2cm into the gastric cardia and involve the gastro-esophageal junction (type III) are staged as gastric adenocarcinoma 4.
This is in contrast to the 7th edition in which gastro-esophageal junction tumors were all staged as esophageal tumors 2.