[1] Seoul Natl Univ, Coll Med, Seoul Natl Univ Bundang Hosp, Dept Internal Med, Songnam, South Korea
[2] Seoul Natl Univ, Coll Med, Seoul Natl Univ Bundang Hosp, Dept Radiat Oncol, Songnam, South Korea
[3] Seoul Natl Univ, Coll Med, Seoul Natl Univ Bundang Hosp, Dept Otorhinolaryngol, Songnam, South Korea
[4] Seoul Natl Univ, Coll Med, Seoul Natl Univ Hosp, Dept Internal Med, Seoul 110744, South Korea
[5] Seoul Natl Univ, Coll Med, Seoul Natl Univ Hosp, Dept Radiat Oncol, Seoul 110744, South Korea
[6] Seoul Natl Univ, Coll Med, Seoul Natl Univ Hosp, Dept Otorhinolaryngol Head & Neck Surg, Seoul 110744, South Korea
[7] Seoul Natl Univ, Coll Med, Canc Res Inst, Seoul 110744, South Korea
[8] Univ Ulsan, Coll Med, Asan Med Ctr, Dept Oncol, Seoul, South Korea
[9] Univ Ulsan, Coll Med, Asan Med Ctr, Dept Radiat Oncol, Seoul, South Korea
[10] Univ Ulsan, Coll Med, Asan Med Ctr, Dept Otolaryngol, Seoul, South Korea
[11] Korea Univ, Coll Med, Korea Univ Anam Hosp, Dept Internal Med, Seoul 136705, South Korea
[12] Korea Univ, Coll Med, Korea Univ Anam Hosp, Dept Otorhinolaryngol Head & Neck Surg, Seoul 136705, South Korea
[13] Catholic Univ Korea, Coll Med, Seoul St Marys Hosp, Dept Internal Med, Seoul, South Korea