A clinical analysis of oropharyngeal squamous cell carcinoma: a single-institution’s experience

Purpose: We herein report the treatment outcome of oropharyngeal squamous cell carcinoma (OPSCC) at Kyushu University Hospital, the total number of OPSCC cases, and changes in the proportion of human papilloma virus (HPV)-related carcinomas over time. Method: We performed a retrospective analysis of 237 cases treated for OPSCC at Kyushu University Hospital between 2013 and 2019. We performed HPV-mRNA in situ hybridization and p16 immunohistochemistry. Result: This study included 197 males (82.1%) and 40 females (17.9%). The disease-specific, progression-free and overall survival (OS) were 69%, 62% and 61%, respectively, over the decade-long study period. p16-Immunohistochemistory and highrisk HPV mRNA in situ hybridization were positive in 114 (48.1%) and 105 (44.3%) cases, respectively. The number of HPV-related OPSCC cases increased according to an annual analysis. HPV⁺ cases had a significantly better prognosis than HPV⁻ cases. In addition, p16⁺/HPV⁻ cases had a significantly worse prognosis than p16⁺/HPV⁺ cases (OS: p = 0.0484). HPV⁺ OPSCC cases were associated with a younger age (< 60 years old) (p = 0.0429), non-smoker (p = 0.0001), lateral tumor site (< 0.00001), lymphoid metastasis (< 0.0001) and low clinical stage (< 0.0001). Conclusion: The frequency of HPV-related OPSCC cases is increasing in Japan as well as worldwide, and such cases are characterized by no smoking habit, a young age, and a good prognosis. Even in p16⁺ OPSCC, HPV⁻ cases had a poor prognosis, suggesting the importance of accurate HPV determination. To determine the intensity of treatment for HPV-related and non-related OPSCC, it is necessary to accumulate cases for the accurate HPV determination and comparison of treatment effects.