Additional parameters to improve the prognostic value of the 8th edition of the UICC classification for human papillomavirus-related oropharyngeal tumors.

Background: The prognostic reliability of the UICC's TNM classification (8th edition) for human papillomavirus (HPV)-positive tonsillar squamous cell carcinomas (TSCCs) compared to the 7th edition was explored, and its improvement by using additional anatomical and nonanatomical parameters.

Methods: One hundred and ten HPV-positive and 225 HPV-negative TSCCs were retrospectively analyzed. Survival was correlated with patient and tumor characteristics (7th and 8th edition UICC TNM classification).

Results: In HPV-positive TSCCs, the 8th edition UICC's TNM classification correlated better with prognosis than the 7th edition. Also, smoking status was a stronger prognosticator of survival than UICC staging. Non- or former smokers had a 5-year overall survival of 95.1% regardless of tumor stage. Furthermore, age (>65 years), cN3, and M1 classification were significant prognostic factors.

Conclusion: The prognostic value of the 8th edition UICC's TNM classification improved significantly when compared to the 7th edition. Nonetheless, further improvement is possible by adding nonanatomical factors (smoking, age >65 year) and separating N0-N2 from N3.