Maciej Rysz1, Romuald Krajewski2. 1. Head and Neck Cancer Department, Memorial Cancer Center Institute of Oncology, Wawelska 15 B Street, 02-034 Warsaw, Poland. Electronic address: riisz@wp.pl. 2. Head and Neck Cancer Department, Memorial Cancer Center Institute of Oncology, Wawelska 15 B Street, 02-034 Warsaw, Poland.