[1] Karolinska Inst, Dept Clin Sci Intervent & Technol, Div ENT Dis, Stockholm, Sweden
[2] Karolinska Univ Hosp, Dept Otorhinolaryngol, Stockholm, Sweden
[3] Karolinska Univ Hosp, Med Unit, Head Neck Lung & Skin Canc, Stockholm, Sweden
[4] Karolinska Inst, Dept Mol Med & Surg, Upper Gastrointestinal Surg, Stockholm, Sweden
[5] Karolinska Univ Hosp, Stockholm, Sweden
[6] Univ Helsinki, Dept Otorhinolaryngol Head & Neck Surg, Helsinki, Finland
[7] Helsinki Univ Hosp, Helsinki, Finland
[8] Karolinska Univ Hosp, Dept Otorhinolaryngol, Eugeniavagen 3, SE-1717 Stockholm, Sweden