Inclusion Criteria:  Males or females, all ages Endoscopic resection of a histologically proven high risk T1a, low risk T1b EAC, or high risk T1b EAC Between 1/1/2008 and 1/1/2019 Endoscopic resection and endoscopic FU (or other treatment after ER) have taken place in the participating center No written or oral refusal to use subject's data  Exclusion Criterium:  Objection against participation in this study