Associated risk factor analysis for positive resection margins after endoscopic submucosal dissection in early-stage gastric cancer.

PURPOSE To investigate the associated risk factors and the prognostic impact of positive resection margins after endoscopic submucosal dissection (ESD) of early-stage gastric cancer. METHODS A retrospective analysis of prospectively collected data was performed on 319 consecutive lesions in 316 patients who underwent ESD. Age, gender, surgeons, lesion location, maximum diameter of resected specimens, macroscopic type, depth of tumor invasion and tumor differentiation were evaluated as potential risk factors. RESULTS A total of 27 (8.5%) patients exhibited positive resection margins after ESD. Among 25 successfully followed-up patients 13 were subjected to gastrectomy, 1 was administered chemotherapy, 2 underwent additional endoscopic resection and 9, who were initially followed-up during a median period of 11.7 months (range 1-40), had neither recurrence nor metastasis. Univariate analysis revealed that age, lesion location, depth of tumor invasion, macroscopic type and tumor differentiation were correlated with positive resection margin. By contrast, multivariate logistic regression analysis showed that only age, tumor differentiation and depth of tumor invasion were independent risk factors of positive resection margins. CONCLUSION Age, tumor differentiation and depth of tumor invasion were independent risk factors for post-ESD positive resection margins. This result suggests that older patients, undifferentiated lesions and a greater depth of invasion increase the risk for post-ESD positive resection margins.