Utilizing the AJCC staging 8th edition to discriminate survival outcomes in HPV-associated oropharyngeal squamous cell carcinoma: A population-based study using the SEER database

Abstract Background 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. We aimed to observe how well the AJCC staging 8th edition precisely discriminate survival outcomes in patients with HPV (+) OPSCC than AJCC staging 7th edition using a large population database. Additionally, we observed survival outcomes when patients were further classified according to other clinical factors. Methods A total of 7448 patients with HPV (+) OPSCC were enrolled using the Surveillance, Epidemiology, and End Results database between 2010 and 2016. 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 each edition were estimated and compared using Kaplan–Meier plots. Results Of the 7448 patients, 6960 patients (93.44%) were down-staged from the 7th to the 8th edition in patients with HPV (+) OPSCC. The AJCC staging 8th edition showed more discriminatory power in predicting survival of patients with HPV (+) OPSCC than the AJCC staging 7th edition, regardless of the primary subsites. Early clinical stage patients with HPV (+) OPSCC showed no significant differences according to the therapeutic methods, unlike those according to the AJCC 7th edition. However, clinical stage I patients with HPV (+) OPSCC according to the AJCC 8th edition showed better prognosis in case of high T staging than high N staging. Clinical staging according to the AJCC 8th edition compared to that of the 7th edition was an independent prognostic factor in patients with HPV (+) OPSCC. Conclusion This large population-based study emphasizes the advantages of the new classification system for discriminating survival in patients with HPV (+) OPSCC according to various factors.