Outcomes of Submucosal Tunneling Endoscopic Resection for Subepithelial Tumors in the Upper Gastrointestinal Tract: Experience from the United States.

Background: Data on outcomes of submucosal tunneling endoscopic resection (STER) for upper gastrointestinal (UGI) subepithelial lesions (SELs) in Western countries is limited. This study assesses the outcomes of STER for UGI SELs in US centers.

Methods: This retrospective analysis included UGI SELs referred for STER at eight US centers. Study included lesions originating or inseparable from the muscularis propria (MP) layer, SELs with symptoms, potential malignancy on endoscopic ultrasound (EUS), or inconclusive EUS-fine needle aspiration (EUS-FNA) but suspected gastrointestinal stromal tumor (GIST).

Results: A total of 47 patients with 51 SELs (median size 25 mm) were included; 42 (82.3%) had prior sampling. Median procedure time was 89.8 minutes. Submucosal fibrosis (SF) was present in 19.6% lesions, all with prior sampling history. En bloc resection and retrieval were achieved in 94.1% lesions. Transmural resection (TMR) was needed in 21.6% of the lesions and was significantly associated with extraluminal extension (OR 8.4), GIST histology (OR 6.0), and SF (OR 5.8). TMR was linked to a higher rate of R1 resection (OR: 4.1) and longer procedural time (>90 minutes, OR 8.6), without an increased risk of adverse events (AEs). AEs occurred in 7/47 (14.8%) patients and were managed conservatively. No lesion recurred within a median follow-up of 17 months.

Conclusions: STER is a safe and effective approach for selected UGI SELs. Extraluminal extension, GIST histology, and SF predict the need for TMR. R1 resection was more common with TMR with increased procedural time. Minimizing pre-resection sampling may reduce fibrosis and optimize outcomes.