Surgery, Nagasaki University School of Medicine Graduate School of Biomedical Sciences, Nagasaki, Japan skuba@nagasaki-u.ac.jp. Surgery, National Hospital Organisation Nagasaki Medical Center, Omura, Nagasaki, Japan. Surgical Oncology, Nagasaki University School of Medicine Graduate School of Biomedical Sciences, Nagasaki, Japan. Surgery, Japanese Red Cross Nagasaki Atomic Bomb Hospital, Nagasaki, Japan. Oral Management Center, Nagasaki University Hospital, Nagasaki, Japan. Surgery, Nagasaki University School of Medicine Graduate School of Biomedical Sciences, Nagasaki, Japan. Surgery, Nagasaki Harbor Medical Center City Hospital, Nagasaki, Japan. Hakujujikai Sasebo Chuo Hospital, Sasebo, Nagasaki, Japan. Pharmacy, Nagasaki University Hospital, Nagasaki, Japan. Clinical Research Center, Nagasaki University Hospital, Nagasaki, Japan. Clinical Oral Oncology, Nagasaki University School of Medicine Graduate School of Biomedical Sciences, Nagasaki, Japan.