Background: Submucosal and lymphovascular (SM/LV) invasions of early gastric cancer (EGC) are difficult to diagnose accurately prior to endoscopic submucosal dissection (ESD), and are occasionally found in resected specimens, requiring additional gastrectomy and lymph node dissection. We performed a retrospective study to determine the risk factors for SM/LV invasions.
Methods: We analyzed clinicopathological data (age, sex, cancer location, gross morphology, multifocality, tumor size, histological differentiation, depth of invasion, and the presence or absence of lymphovascular invasion) in patients receiving ESD between 2007 and 2012 and presenting with EGC of 2.0 cm or smaller in size, a differentiated-type adenocarcinoma, and without ulceration.
Results: Of 208 lesions consecutively resected by ESD, 143 lesions in 132 patients were included in this study. Submucosal and lymphovascular invasions were detected in 16 lesions. Multivariate analysis revealed three independent risk factors for SM/LV invasions: dominant histology of moderately-differentiated or papillary adenocarcinoma, gross type of 0-IIa + IIc or IIc + IIa, and tumor size of ≥1.5 cm. Lesions exhibiting more than two of these three risk factors were associated with having a 47 % increased incidence of SM/LV invasion (odds ratio 15; 95 % confidence interval 4.6-49.0; P < 0.0001).
Conclusions: Moderately-differentiated or papillary adenocarcinoma, 0-IIa + IIc or IIc + IIa, and a tumor size of ≥1.5 cm were identified as independent risk factors for SM/LV invasion among EGCs which appeared to be an endoscopically good indication for ESD. Careful surveillances including endoscopic ultrasonography or enhanced computed tomography might be needed for high risk patients before ESD.