Risk factors for local recurrence in patients with positive lateral resection margins after endoscopic submucosal dissection for early gastric cancer

Background With the widespread use of endoscopic submucosal dissection (ESD) in patients with early gastric cancer (EGC), the number of cases with incomplete resection due to positive lateral resection margins (LM+) is increasing. Local recurrence, which occurs frequently in LM+ cases, is an important issue. This study aimed to clarify the clinicopathological factors related to tumor recurrence in LM+ cases after ESD for EGC. Methods From January 2005 to December 2012, a total of 1,083 patients with EGC underwent ESD at our hospital. Of these, cases with a pathological diagnosis of LM+ were included in this study. Patients with positive vertical resection margins, those who underwent surgical resection immediately or were followed up for less than 6 months after ESD, were excluded. Results A total of 55 LM+ cases after ESD for EGC were enrolled. Incorrect delineation of a lesion that extended pathologically beyond the ESD marking dots was the main cause of LM+. Local recurrence was found in 20 (36.4 %) patients (median follow-up period, 23 months). Local recurrence rates related to LM+ length were as follows: 7/29 (24.1 %) in 2 mm, 6/16 (37.5 %) in 4 mm, 1/3 (33.3 %) in 6 mm, 4/5 (80 %) in 8 mm, and 2/2 (100 %) in a parts per thousand yen10 mm. In multivariate analysis, tumor size > 2 cm (OR 4.48, 95 % CI 1.18-16.99, p = 0.027), and LM+ length > 6 mm (OR 7.65, 95 % CI 1.15-50.70, p = 0.035) were independent risk factors for tumor recurrence. Conclusion To decrease the risk of LM+, it is highly important to accurately delineate the lateral margins during ESD; when the final histopathological result is LM+, cases with LM+ length > 6 mm or tumor size > 2 cm should be considered for additional surgical resection or re-ESD because of a high risk of tumor recurrence.