LAUSR

519Background: Because of unclear clinicopathologic features, the optimal surgical procedure for duodenal gastrointestinal stromal tumor (GIST) remains poorly defined. We analyze clinicopathological features and recommend optimal surgical treatment of duodenal GIST. Methods: From July, 2000 to April 2017, 118 patients who had localized duodenal GIST were treated by curative surgical resection at a single institution. We retrospectively reviewed the clinicopathological characteristics and survival outcomes. Results: In survival analysis of all patients, 5-year overall survival (OS) and disease-free survival (DFS) rate were 94.9 and 79.2%, respectively. 19 patients developed recurrent disease at a median of 26.1 months from surgery and most common recurrence site was liver (63.2%). In multivariate analysis, mitotic count was the statistically significant prognostic factors of DFS. Our 20 cases of duodenal GIST in 1st or 4th portion were completely resected by limited resection(LR), regardless of tumor size....