Submucosal Tunneling Endoscopic Resection for Upper Gastroin
Objective: The aim of this study is to evaluate the long-term outcomes of a large series of patients treated with submucosal tunneling endoscopic resection (STER).

Background: STER is a newly developed treatment for upper gastrointestinal submucosal tumors originating from the muscularis propria layer. Recently, reports about STER are increasing, but a large study with long-term follow-up is little known.

Methods: In a retrospective study, a total of 180 patients with upper gastrointestinal submucosal tumors undergoing STER were included from June 2011 to May 2013. Clinicopathological, endoscopic, and follow-up data were collected and analyzed.

Results: The en bloc resection was achieved in 90.6% of patients and the complications rate was 8.3%. Based on statistical analysis, tumors with irregular shape and greater size were the significant contributors to piecemeal resection and long operative times. Besides tumor shape and size, tumor in deep muscularis propria and long operative time were also risk factors of complications. The median hospitalization time was 3.2 days. All of the complications were cured by conservative treatment. A median follow-up of 36 months was available and all patients were free from local recurrence or distant metastasis during the study period.

Conclusions: STER is an effective and safe methodology for the resection of upper gastrointestinal submucosal tumors. Tumor size and shape impact on the piecemeal resection rate and procedural difficulty. STER for large tumors with irregular shape in the deep muscularis propria is also feasible but associated with relatively high risks of piecemeal resection and complications..