[1] Univ Cologne, Fac Med, Dept Otorhinolaryngol Head & Neck Surg, D-50931 Cologne, Germany
[2] Univ Hosp Cologne, Inst Pathol, Cologne, Germany
[3] Univ Cologne, Dept Oral & Craniomaxillo & Facial Plast Surg, D-50931 Cologne, Germany
[4] Univ Hosp Cologne, Dept Radiat Oncol, Cologne, Germany
[5] Univ Sydney, Whiteley Martin Res Ctr, Discipline Surg, Sydney, NSW 2006, Australia
[6] Univ Hosp Giessen, Dept Otorhinolaryngol Head & Neck Surg, Giessen, Germany
[7] Univ Cologne, Jean Uhrmacher Inst Otorhinolaryngol Res, D-50931 Cologne, Germany