Role of high-risk human papillomavirus in the etiology of oral and oropharyngeal cancers in Thailand: A case-control study

Background: Among developing countries, Thailand shows no increase in the incidence of human papillomavirus-driven oropharyngeal cancer. The causal role of human papillomavirus infection in this pathology has not been researched thoroughly. Methods: A hospital-based, case-control study was performed which included 104 patients with newly diagnosed oral and oropharyngeal squamous cell carcinomas and 104 individuals without cancer. The Cervista high-risk human papillomavirus and 16/18 assays were used to detect human papillomavirus. Odds ratios were used to assess the association between high-risk genotypes of human papillomavirus and the cancers. Results: High-risk human papillomavirus was detected in 4 of 52 (7.7%) oral cancer cases, 6 of 52 (11.5%) oropharyngeal cancer cases, and 1 of 104 (0.96%) control subjects. Of 104 cancer patients in the study, 83 were smokers. High-risk human papillomavirus was significantly associated with oropharyngeal cancer (odds ratio=13.44, 95% confidence interval=1.6-114.8) but was nonsignificantly associated with oral cancer (odds ratio=8.58, 95% confidence interval=0.9-78.9). However, after adjustment for smoking, high-risk human papillomavirus was determined to be nonsignificantly associated with oropharyngeal cancer (adjusted odds ratio=5.83, 95% confidence interval=0.8-43.5). Conclusion: Although low human papillomavirus prevalence was observed, the rate of high-risk human papillomavirus infection in the cancer group was still higher than that in the control group. Smoking may have an influence on the etiology of human papillomavirus-related cancers. However, the study is underpowered to clarify the role of human papillomavirus as the independent risk factor for oral and oropharyngeal cancers in the Thai population.