Objective: To investigate the differences and similarities of the risk factors(especially lesion size) of lymph node metastasis(LNM) between stage T1a and T1b esophageal squamous cell carcinoma (ESCC), and to further refine the indications of endoscopic radical treatment for early stage esophageal carcinoma.Methods: Retrospective analysis was performed for the patients who received esophagectomy were diagnosed with T1-stage ESCC pathologically in Fudan University Shanghai Cancer Center from January 2010 to ...