Background: The TNM (tumor, nodes, metastasis) classification is updated periodically according to the literature and international recommendations. With the 8th edition, notable changes have been developed especially with regard to oropharyngeal cancer.
Materials and methods: The modifications as well as the practicability of the classification for staging of oropharyngeal cancers are demonstrated on the basis of cases from the tumor database.
Results: The latest edition of the TNM classification realizes requirements to differentiate between human papilloma virus (HPV) positive and HPV-negative tumors during staging. Furthermore, the prognostic relevance of extranodal extension of lymph node metastases was integrated into the classification. While downstaging is performed regarding N category and Union Internationale Contre le Cancer (UICC) stage in many p16-positive tumors, for p16-negative tumors, extranodal spread mostly leads to a notable upstaging. Due to limited specificity of the p16 immunostaining, the relevance of false positive results has to be underlined. Missing integration of smoking behavior, limited standardization of the extranodal extension examination technique, as well as high demands on the documentation quality should be kept in mind.
Conclusion: Clinical trials will have to show whether deescalation strategies regarding p16-positive carcinomas are supported by the changes made in the TNM staging system. A prospective multicenter study should examine the universal applicability, the appropriateness for all sublocations, as well as the prognostic significance of the current edition.
Keywords: Extranodal extension; HPV DNA tests; Head and neck neoplasms; Papillomaviridae; p16 immunhistochemistry.