Synergistic Effect of Lymphatic Invasion and Venous Invasion on the Risk of Lymph Node Metastasis in Patients with Non-Curative Endoscopic Resection of Early Gastric Cancer.

Background: Although additive radical surgery is recommended for patients with non-curative endoscopic resection for early gastric cancer (EGC), lymph node (LN) metastasis or remnant tumor is detected in only about 10% of patients. Therefore, we aimed to identify patients who required surgery by identifying significant risk factors for LN metastasis and evaluate long-term outcomes in patients with non-curative endoscopic resection.

Methods: We retrospectively analyzed the database of Seoul National University Hospital to identify patients who underwent endoscopic resection for EGC from June 2005 to December 2016.

Results: Three hundred and twenty-nine patients did not meet the criteria for curative resection after endoscopic resection. Among them, 140 patients underwent additional surgery and 171 patients refused surgery and regularly received follow-up. In the surgery group, LN metastasis was found in 12.1% of patients. Logistic regression analysis revealed that the rate of LN metastasis was significantly higher in patients with lymphatic invasion (LI) (odds ratio [OR] 5.84, p = 0.014) and venous invasion (VI) (OR 5.66, p = 0.006). We analyzed LN metastasis based on LI and VI in the surgical group. LN metastasis was significantly increased in the positive LI and VI groups compared with the negative LI and VI groups (OR 68.32; 95% confidence interval, 4.74-984.82; p = 0.002).

Conclusions: Both LI and VI were significant predictors of LN metastasis. The risk of LN metastasis was augmented when both LI and VI were positive. Therefore, LI and VI should be evaluated separately in patients with non-curative endoscopic resection. Additive surgery should be recommended for patients with LI and/or VI.