Tumor Size And The Risk For Lymph Node Metastases In T1 Esophageal Adenocarcinoma

332 Background: Adjuvant therapy after endoscopic resection (ER) of T1 EAC in non-surgical candidates is largely based on the risk of LNM. Risk factors for LNM in T1 EAC are not clearly defined. Our aim is to evaluate risk factors for LNM in T1 EAC patients following esophagectomy or ER with ≥ 5 years of follow-up. Methods: This is a retrospective analysis at a large tertiary referral center. Our pathology database identified patients who underwent esophagectomy or ER with ≥ 5 years follow-up, with histologically proven T1 EAC from 2010-2017. Patients were excluded if they (a) received chemoradiation prior to esophagectomy or before/after ER (b) had any other primary cancer treated within the previous 5 years. Specimens were reviewed by an expert GI pathologist for accuracy. Results: Of 80 patients [85% males], 61 (76%) underwent esophagectomy and 19 (24%) underwent ER. Twelve (15%) developed LNM per study criteria. Tumor size was significantly (p-value 0.014) associated with risk of LNM (Table). No other factors including lymphovascular invasion, differentiation on pathology, macroscopic appearance, infiltration growth pattern, or tumor distance from the gastroesophageal junction were significant risk factors for LNM. Conclusions: In T1 EAC, tumor size appears to be a significant risk factor for LNM at five years following surgical or endoscopic resection. Adjuvant therapy should be considered in patients with larger tumor size. [Table: see text]