1. Department of Surgery, Oda Municipal Hospital , 1428-3 Oda-cho Yoshinaga, Oda, Shimane 694-0063 , Japan
2. Faculty of Medicine , Department of General Medicine, , 89-1 Enya-cho, Izumo, Shimane 693-8501 , Japan
3. Shimane University , Department of General Medicine, , 89-1 Enya-cho, Izumo, Shimane 693-8501 , Japan
4. Faculty of Medicine , Department of Digestive and General Surgery, , 89-1, Enya-cho, Izumo City, Shimane 693-8501 , Japan
5. Shimane University , Department of Digestive and General Surgery, , 89-1, Enya-cho, Izumo City, Shimane 693-8501 , Japan