[1] Kobe Univ, Dept Otolaryngol Head & Neck Surg, Grad Sch Med, 7-5-1 Kusunoki Cho, Kobe, Hyogo 6500017, Japan
[2] Kobe Univ, Dept Diagnost Pathol, Grad Sch Med, 7-5-1 Kusunoki Cho, Kobe, Hyogo 6500017, Japan
[3] Kobe Univ, Dept Radiat Oncol, Grad Sch Med, Kobe, Hyogo, Japan
[4] Kobe Univ, Dept Med Oncol & Hematol, Grad Sch Med, Kobe, Hyogo, Japan