Clinicopathological characteristics and lymph node metastasis rates in early gastric lymphoepithelioma-like carcinoma: Implications for endoscopic resection.

Abstract

321 Background: We aimed to clarify the clinicopathological features and the rate of lymph node metastases (LNM) of early gastric lymphoepithelioma-like carcinoma (LELC). Methods: We compared the clinicopathological characteristics of 82 LELC and 5758 well- or moderately differentiated (WD or MD) tubular adenocarcinoma patients who received gastrectomy for single early gastric cancer (EGC). Results: Compared to the control group, early LELC patients were younger, had a higher prevalence of proximally located tumors, more frequent Epstein-Barr virus (EBV) infection, more frequent deep submucosal invasion (SM2 or SM3, 85.4% versus 29.9%, P < 0.001) but less frequent lymphatic invasion (4.9% versus 16.2%, P = 0.009). Among tumors with deep submucosal invasion, early LELC patients had smaller tumor sizes, less frequent lymphatic invasion (5.7% versus 40.1%, P < 0.001) and a lower rate of LNM (7.1% versus 19.4%, P = 0.016) than the control group. LNM rates of LELC patients with mucosal, shallow submucosal invasion (SM1) and deep submucosal invasion were 0%, 0%, and 7.1%, respectively. Lymphatic invasion was the only significant risk factor in the regression analysis for LNM in LELC patients. Among 12 patients with mucosal or shallow submucosal invasion and 27 patients with deep submucosal invasion having small tumor sizes (less than 2 cm) and no lymphatic invasion, there was no LNM. Conclusions: Given the low rate of LNM, the same curability criteria of ESD for WD or MD EGC may be applied to early LELC and even more flexibly for those considered non-curative ESD only because of deep submucosal invasion.