Clinicopathological Characteristics and Lymph Node Metastasis Rates in Early Gastric Lymphoepithelioma-Like Carcinoma: Implications for Endoscopic Resection.

Background/aims: Lymphoepithelioma-like carcinoma (LELC) is a rare subtype of gastric cancer. We aimed to identify the clinicopathological features and rate of lymph node metastasis (LNM) to investigate the feasibility of endoscopic submucosal dissection for early gastric LELC confined to the mucosa or submucosa.

Methods: We compared the clinicopathological characteristics of 116 early gastric LELC patients and 5,753 early gastric well- or moderately differentiated (WD or MD) tubular adenocarcinoma patients treated by gastrectomy.

Results: Compared to WD or MD early gastric cancer (EGC) patients, early LELC patients were younger and had a higher prevalence of proximally located tumors. Despite more frequent deep submucosal invasion (86.2% vs 29.8%), lymphatic invasion was less frequent (6.0% vs 16.2%) in early LELC patients than in WD or MD EGC patients. Among tumors with deep submucosal invasion, the tumor size was smaller, lymphatic invasion was less frequent (6.0% vs 40.2%) and the rate of LNM was lower (10.0% vs 19.4%) in patients with LELC than in those with WD or MD EGC. The overall rate of LNM in early LELC patients was 8.6% (10/116). The risk of LNM in patients with mucosal, shallow submucosal invasive, or deep submucosal invasive LELC was 0% (0/6), 0% (0/10), and 10% (10/100), respectively.

Conclusions: Early LELC is a distinct subtype of EGC with more frequent deep submucosal invasion but less lymphatic invasion and LNM than WD or MD EGCs. Endoscopic submucosal dissection may be considered curative for patients with early LELC confined to the mucosa or shallow submucosa, given its negligible rate of LNM.