Tumor Budding and Other Risk Factors of Lymph Node Metastasis in Submucosal Early Gastric Carcinoma

Compared with early gastric intramucosal carcinoma, submucosal carcinoma is known to have a higher risk for lymph node metastasis (LMN), but risk factors in submucosal carcinoma remain elusive. In this multicenter study with 621 radical gastrectomies for submucosal early gastric carcinoma, we investigated tumor budding and other risk factors of LMN that were identified in 172 cases (27.7%). Overall, independent high-risk factors for LMN included lymphovascular invasion (odds ratio, 3.9; 95% confidence interval, 2.5-6.1), tumor budding (odds ratio, 3.3; 95% confidence interval, 1.9-5.9), mixed tubular/papillary adenocarcinoma with poorly cohesive carcinoma (odds ratio, 2.1; 95% confidence interval, 1.0-4.3), and female sex (odds ratio, 1.6; 95% confidence interval, 1.0-2.6), whereas gastric cardiac submucosal carcinomas had a significantly lower risk for LMN (odds ratio, 0.5; 95% confidence interval, 0.3-0.9). In 276 well/moderately differentiated tubular or papillary submucosal early gastric carcinomas, independent risk factors were tumor budding (odds ratio, 3.7; 95% confidence interval, 1.6-8.7), deep submucosal (SM2) invasion (odds ratio, 3.1; 95% confidence interval, 1.3-7.6), and lymphovascular invasion (odds ratio, 2.7; 95% confidence interval, 1.3-5.6). In 174 cases without tumor budding and lymphovascular invasion, no LMN was identified in 47 cardiac tumors, and 15 tumors <1.0 cm in size. In conclusion, tumor budding, lymphovascular invasion, mixed tubular/papillary adenocarcinoma with poorly cohesive carcinoma, and female gender were found to be significant high-risk factors for LMN in submucosal early gastric carcinoma, while submucosal gastric cardiac carcinoma had a significantly lower risk for nodal metastasis.