Utilizing the AJCC 8th Staging to Discriminate Survival Outcomes in HPV-associated Oropharyngeal Squamous Cell Carcinoma

Abstract

Background/aim: The American Joint Committee on Cancer (AJCC) staging 8th edition introduced major changes in the TNM staging of oropharyngeal squamous cell carcinoma (OPSCC) based on the human papillomavirus (HPV) status. This study aimed to observe how well the AJCC staging 8^th edition precisely discriminates survival outcomes in patients with HPV-associated OPSCC using a large population database.

Materials and methods: Using the Surveillance, Epidemiology, and End Results database between 2010 and 2016, 7,448 patients with HPV-associated OPSCC were enrolled. Patients diagnosed with OPSCC and tested positive for HPV with information on the TNM staging according to the AJCC staging 7th edition were selected. Next, T-, N-, and clinical staging were reconstructed based on the AJCC staging 8th edition. Survival probabilities in both AJCC staging 7^th and 8^th editions were estimated and compared.

Results: Most patients (93.44%) were down-staged from the 7^th to the 8^th edition. The AJCC staging 8^th edition showed more discriminatory power in predicting survival of patients with HPV-associated OPSCC than the AJCC staging 7^th edition, regardless of the primary subsites. Additionally, clinical stage I patients with HPV-associated OPSCC according to the AJCC 8^th edition showed better prognosis in case of high T staging than high N staging. Clinical staging according to the AJCC 8^th edition compared to that of the 7^th edition was an independent prognostic factor in patients with HPV-associated OPSCC.

Conclusion: This study emphasizes the advantages of the new classification system for discriminating survival in HPV-associated OPSCC according to various factors.

Keywords: AJCC; HPV; Oropharyngeal squamous cell carcinoma; SEER; TNM; overall survival.