Department of Pancreatic and Gastric Surgery;
National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital;
Chinese Academy of Medical Sciences and Peking Union Medical College;
Beijing 100021;
China;
Department of Gastric Surgery;
Yun Cheng Center Hospital;
Yucheng 043300;
Shanxi Province;
China;
Duodenal gastrointestinal stromal tumors; Whipple; Surgery; Tumor size; Tumor risk grade;