Risk factors of lymph node metastasis in T1 esophageal squamous cell carcinoma

Background and Aim: To perform endoscopic mucosal resection (EMR) for T1 esophageal cancer, it is essential to estimate the lymph node status exactly. In order to evaluate the feasibility of EMR for esophageal cancers, we evaluated the clinicopathological features of T1 esophageal squamous carcinomas with an emphasis on the risk factors and distribution patterns of lymph node metastasis. Methods: From 1994 to 2006, a total of 200 patients with T1 esophageal carcinoma were treated surgically in our institution. Among them, clinicopathological features were evaluated for 197 consecutive patients with T1 squamous cell carcinoma. Results: The frequency of lymph node involvement was 6.25% (4/64) in mucosal cancers and 29.3% (39/133) in submucosal cancers (P < 0.001). In patients with M1 (n = 32) and M2 (n = 14) cancers, no lymph node metastasis was found. In multivariate analysis, size larger than 20 mm, endoscopically non‐flat type, and endo‐lymphatic invasion were significant independent risk factors for lymph node metastasis. The differentiation of tumor cell was not a risk factor for lymph node metastasis. Conclusions: We suggest that EMR may be attempted for flat superficial squamous esophageal cancers smaller than 20 mm. After EMR, careful histological examination is mandatory.