Surgical treatment The primary is considered radically resected if macroscopic and histologic evaluation approved resection margins without tumor residuals (R0 status). For surgical proceeding a safety margin of at least 1cm is established. For surgical considerations of lymph node resection the tumor localization is divided in level I (below occlusional plane) and level II (above occlusional plane) respecting pre-, postcanine or retromolar finding in addition. Classification of cervical regions follows the recommendations of Robbins from 2002. Hence, the neck is divided into 6 different sections.