Prevalence, clinicopathological characteristics, and outcome of human papillomavirus-associated oropharyngeal cancer in Southern Chinese patients

Background: While the global incidence of human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma (OPSCC) is increasing, there is little information on southern Chinese population available. Methods: We analyzed 207 patients which constituted 63.5% of all newly diagnosed OPSCC in Hong Kong during a 5-year period from 2005 to 2009. Results: We used E6/7 mRNA as a marker of oncogenic involvement and found 20.8% (43/207) of OPSCC and 29.0% (36/124) of tonsillar SCC were associated with HPV. HPV-16 was identified in all cases except one (HPV-18). Patients with HPV-associated OPSCC were significantly younger than HPV-negative patients (mean age: 59.8 vs 63.9 years, P=0.05). Multivariate analysis showed that HPV-associated OPSCC was more likely to occur in non-smokers (39.5 vs. 15.1%, OR: 2.89, P=0.05), non-drinkers (52.5 vs. 25.6%, OR: 2.72, P=0.04), originate from the palatine tonsils (83.7 vs. 53.7%, OR: 3.88, P=0.01), present with an early primary tumor (T1/2) (79.1 vs. 47.6%, OR: 3.81, P=0.004), and exhibit basaloid differentiation (33.3 vs. 7.3%, OR:19.74, P=0.006). HPV positivity was an independent predictor for better prognosis for both 5-years overall and 5-year disease-specific survivals (63.0% vs 29.7%, HR: 0.33, P<0.001, and 87.8% vs 42.6%, HR: 0.16, P<0.001, respectively). Conclusion: The estimated age-standardized incidence of OPSCC in Hong Kong during the period 2005-2009 was 0.12/100,000/year. Impact: This study has provided the most comprehensive clinical and pathological information to date about this newly recognized disease in southern Chinese. In view of the global trend, we should anticipate and prepare for an increase in HPV-related OPSCC in southern China.