Incidence trends in head and neck cancers and human papillomavirus (HPV)-associated oropharyngeal cancer in Canada, 1992-2009

Recently, human papillomavirus (HPV) infection has been causally associated with a subset of head and neck cancers, particularly oropharyngeal cancer. As national cancer reporting systems typically report incidence rates of oropharyngeal cancer grouped with other cancers of the head and neck region, the objective of this study was to present age-standardized incidence trends in oropharyngeal cancer Canada-wide. Data were obtained from the Canadian Cancer Registry for cases diagnosed between 1992 and 2009. Trends in age-standardized incidence rates were described for head and neck cancers overall and for HPV-associated oropharyngeal cancer using Joinpoint regression. The age-standardized incidence of head and neck cancers declined significantly in Canada from 1992 to 1998 (annual percentage change [APC] = -3.0, p < 0.01), then remained stable through to 2009. In contrast, the age-standardized incidence of HPV-associated oropharyngeal cancer increased significantly during the same time period, from 1.6 per 100,000 in 1992 to 2.6 in 2009 (APC = 2.7, p < 0.001). The increase in HPV-associated oropharyngeal cancer was greater in males than in females and increased significantly in all age groups, particularly those aged 50-59 (APC = 5.4, p < 0.001). The age-standardized incidence rate of head and neck cancer overall was stable or declined in all age groups except those aged 50-59 where incidence decreased from 1992 to 1997, then increased through to 2009. The incidence patterns of HPV-associated oropharyngeal cancer and head and neck cancer overall show contrasting trends. Findings highlight the need to surveil HPV-associated oropharyngeal cancer separately from other cancers of the head and neck region in order to monitor these emerging trends.