Indication for endoscopic treatment based on the risk of lymph node metastasis in patients with Siewert type II/III early gastric cancer

Background: Because of the poor prognosis of proximal gastric cancers, there is debate as to whether the conventional indications for endoscopic resection can be used. Methods: Among subjects who underwent surgery for esophagogastric junction or gastric cardia cancer, 256 patients with T1 type II/III of the Siewert classification were included in this study. The association of lymph node metastasis (LNM) with each variable was analyzed using logistic regression models. A receiver operating characteristic curve was used to determine the discriminatory ability of the model. Propensity score-matched non-cardia cancer patients were selected to compare LNM and long-term survival rates. Results: Of the 256 patients with T1 Siewert II/III gastric cancer, 21 (8.2%) had LNM. Because there was no LNM in T1a cancers, risk factors were analyzed only in patients with T1b. Tumor size (OR 1.42, 95% CI 1.10–1.82, P = 0.007) and lymphovascular invasion (LVI) (OR 5.13, 95% CI 1.88–14.06, P = 0.002) were determined to be predictors of LNM (sensitivity = 66.7% and specificity = 81.6%). Among patients without LVI, the groups with negligible risk for LNM were mucosa-confined cancer, or SM1 cancer with a tumor size ≤3 cm. No LNM was observed in patients satisfying the absolute or extended criteria for endoscopic resection of early gastric cancers. LNM and long-term survival rates of patients with Siewert II/III did not differ significantly compared with matched non-cardia cancer patients. Conclusions: Tumor size and LVI were associated with LNM in patients with early Siewert type II/III gastric cancer, and the expanded indication for endoscopic resection may be used.