LAUSR

38 Background: Adequate tissue acquisition is important in making treatment decisions for patients with upper gastrointestinal subepithelial tumors (SETs). This study aimed to compare the outcomes of endoscopic ultrasonography-guided fine-needle biopsy (EUS-FNB) with those of the unroofing biopsy technique. Methods: This study was a single-center, prospective comparative study conducted at Severance Hospital, Yonsei University College of Medicine. A total of 39 patients with SETs ≥15 mm were enrolled between January 2016 and August 2017. Results: Of the 39 patients, 28 underwent biopsy with both techniques (4 underwent only unroofing and 7 underwent only EUS-FNB). The mean tumor size was 21.0 mm (median, 19.0 mm; 15.0–45.0 mm). Histological diagnosis was made with EUS-FNB in 64.3% and with unroofing biopsy in 78.6% (p = 0.344), and immunohistochemical diagnosis was made with EUS-FNB in 46.4% and unroofing biopsy in 67.9% (p = 0.180). In the subgroup analysis (28 patients), there was no significant difference in diagnostic yield between the 2 methods. The mean procedural time with EUS-FNB was shorter than that with unroofing biopsy (p < 0.001). The larger SET (≥ 20 mm) (p = 0.035) and satisfaction of procedure (p = 0.019) were positively associated with successful histological diagnosis by EUS-FNB. No complications were reported with both methods. Conclusions: There was no significant difference in the histological diagnostic yield for SETs between the EUS-FNB and unroofing biopsy techniques. Further study is needed to confirm the efficacy of EUS-FNB and unroofing biopsy in a larger study population. Clinical trial information: NCT02646241.