Abstract
BACKGROUND: Persistent high-risk human papillomavirus (HPV) infection is one of the major etiologies of oropharyngeal squamous cell carcinoma (OPSCC). This study aimed to determine the proportion, temporal trend, and prognostic significance of HPV-related OPSCC in Thai patients. METHODS: The study included patients with OPSCC who were treated at Songklanagarind Hospital (Songkhla, Southern Thailand) from 2009 to 2020. HPV status was screened by p16 expression using immunohistochemistry and confirmed by real-time polymerase chain reaction. Cox regression was used to determine prognostic significance. RESULTS: The overall proportion of HPV+ OPSCC was 15.3% (95% confidence interval [CI]: 12.1-18.5) with a slightly increased proportion from 10.6% in 2009-2010 to 16.5% (2019-2020) (P for trend = 0.166). Among the HPV+ cases, HPV16 was detected in 65.3%, HPV18 in 34.7%, and other high-risk HPV types in 24%. Patients with P16+ or HPV+ OPSCC had significantly better overall survival (hazard ratio [HR]: 0.63, 95% CI: 0.45-0.90 and HR: 0.63, 95% CI: 0.45-0.88, respectively). CONCLUSION: Thai patients in the southern region have a low proportion of HPV-related OPSCC with an increasing trend. Both P16 expression and HPV DNA status are strong independent prognostic factors of OPSCC.