Incidence of head and neck cancer and socioeconomic status in Canada from 1992 to 2007

Objective: To investigate the association between head and neck cancer (HNC) incidence and socioeconomic status (SES) in Canada, and investigate changes in the relationship between HNC incidence and SES from 1992 to 2007.

Materials and methods: Cases were drawn from the Canadian Cancer Registry (1992-2007), and were categorized into three subsites: oropharynx, oral cavity, and "other" (hypopharynx, larynx, and nasopharynx). Demographic and socioeconomic information were extracted from the Canadian Census of Population data for the study period (1992-2007), which included four census years. We linked cases to income quintiles (InQs) according to patients' postal codes.

Results: Incidence rates in the lowest InQs were significantly higher than in the highest InQs for all HNC subsites. The incidence of oropharyngeal cancer increased over the time period 1992-2007 for all InQs. However, the greatest increase in incidence was in the highest InQs. As a result, over the time period the gap between the incidence of the highest and lowest InQs significantly narrowed for oropharyngeal cancer. For oral cavity cancer and the other head and neck cancers, the overall incidence did not increase and the gap in incidence did not change significantly.

Conclusion: HNC incidence was higher with lower income in all HNC subsites in Canada from 1992 to 2007. The gap in incidence between the highest and the lowest InQs narrowed for oropharyngeal cancer over the time period studied, but was unchanged for the other HNC subsites.