Risk factors and management of positive horizontal margin in early gastric cancer resected by en bloc endoscopic submucosal dissection.

Background: Although endoscopic submucosal dissection (ESD) is a widely accepted treatment for early gastric cancer (EGC), there is no consensus regarding the management of positive horizontal margin (HM) despite en bloc ESD. The aim of the current study was to identify the risk factors and optimal management of positive HM in EGCs resected by en bloc ESD.

Methods: A total of 890 consecutive patients with 1,053 intramucosal EGCs resected by en bloc ESD between April 2005 and June 2011. Clinicopathological data were retrieved retrospectively to assess the positive HM rate, local recurrence rate, risk factors for positive HM, and outcomes of treatment for local recurrent tumor. Positive HM was defined as a margin with direct tumor invasion (type A), the presence of cancerous cells on either end of 2-mm-thick cut sections (type B), or an unclear tumor margin resulting from crush or burn damage (type C).

Results: The positive HM rate was 2.0% (21/1,053). The local recurrence rate was 0.3% (3/1,053). All local recurrent tumors were intramucosal carcinomas, and were resected curatively by re-ESD. Multivariate analysis with logistic regression showed tumor location in the upper third of the stomach and lesions not matching the absolute indication to be independent risk factors for positive HM.

Conclusion: The risk factors for HM positivity in cases of EGC resected by en bloc ESD are tumor location in the upper third of the stomach and dissatisfaction of the absolute indication for curative ESD.