AIM To evaluate the incidence of lymph node metastasis(LNM) and its risk factors in patients with Siewert type Ⅰ and type Ⅱ pT1 adenocarcinomas.METHODS We enrolled 85 patients [69 men, 16 women; median age(range), 67(38-84) years] who had undergone esophagectomy or proximal gastrectomy for Siewert type Ⅰ and type Ⅱ pT1 adenocarcinomas. Predictive risk factors of LNM included age, sex, location of the tumor center, confirmed Barrett’s esophageal adenocarcinoma, tumor size, macroscopic tumor type, pathology, invasion depth, presence of ulceration, and lymphovascular invasion. Multivariate logistic regression analysis was used to identify factors predicting LNM. We also evaluated the frequencies of LNM for Siewert type Ⅰ and type Ⅱ pT1 adenocarcinomas in meta-data analysis.RESULTS LNMs were found in 11 out of 85 patients(12.9%, 95%CI: 5.8-20.0). Only 1 of the 15 patients(6.6%, 95%CI: 0.0-19.2) who had a final diagnosis of pT1a adenocarcinoma had a positive LNM, whereas 10 ofthe 70 patients(14.2%, 95%CI: 6.0-22.4) with a final diagnosis of pT1b adenocarcinoma had positive LNM. Furthermore, only one of the 30 patients(3.3%, 95%CI: 0.0-9.7) with a tumor invasion depth within 500 μm from muscularis mucosae had positive LNM. Poor differentiation and lymphovascular invasion were independently associated with a risk of LNM. In meta-data analysis, 12 of the 355 patients(3.3%, 95%CI: 1.5-5.2) who had a final diagnosis of pT1a adenocarcinoma had a positive LNM, whereas 91 of the 438 patients(20.7%, 95%CI: 16.9-24.5) with a final diagnosis of pT1b adenocarcinoma had positive LNM. CONCLUSION We consider endoscopic submucosal dissection(ESD) is suitable for patients with Siewert type Ⅰ and type Ⅱ T1 a adenocarcinomas. For patients with T1b adenocarcinoma, especially invasion depth is within 500 μm from muscularis mucosae with no other risk factor for LNM, diagnostic ESD could be a treatment option according to the overall status of patients and the presence of comorbidities. AIM To evaluate the incidence of lymph node metastasis (LNM) and its risk factors in patients with Siewert type I and type II pTl adenocarcinomas. METHODS We enrolled 85 patients [69 men, 16 women; median age (range), 67 (38- 84) years] who had undergone esophagectomy or proximal gastrectomy for Siewert type I and type II pT1 adenocarcinomas. Predictive risk factors of LNM included age, sex, location of the tumor center, confirmed Barrett’s esophageal adenocarcinoma, tumor size, macroscopic tumor type, pathology , invasion depth, presence of ulceration, and lymphovascular invasion. Multivariate logistic regression analysis was used to identify factors predicting LNM. We also evaluated the frequencies of LNM for Siewert type I and type II pT1 adenocarcinomas in meta-data analysis. Only 1 of the 15 patients (6.6%, 95% CI: 0.0-19.2) who had a final diagnosis of pT1a adenocarcinoma had a positive LNM, even 10 ofth with only 1 of 30 patients (3.3%, 95% CI: 0.0-9.7) with a tumor invasion (14.2%, 95% CI: 6.0-22.4) with a final invasion of pT1b adenocarcinoma had positive LN In meta-data analysis, 12 of the 355 patients (3.3%, 95% CI: 1.5-5.2) who had a final diagnosis of pT1a adenocarcinoma had a positive LNM, whereas 91 of the 438 patients (20.7%, 95% CI: 16.9-24.5) with a final diagnosis of pT1b adenocarcinoma had positive LNM. CONCLUSION We consider endoscopic submucosal dissection (ESD) is Suitable for patients with Siewert type I and type II T1 a adenocarcinomas. For patients with T1b adenocarcinoma, especially invasion depth is within 500 μm from muscularis mucosae with no other risk factor for LNM, diagnostic ESD could be a treatment option according to the overall status of patients and the presence of com orbidities.