Sociodemographic differences in the incidence of oropharyngeal and oral cavity squamous cell cancers in New Zealand.

OBJECTIVE: To determine whether the incidence of oropharyngeal and oral cavity squamous cell cancers differs by subsite, age, gender, ethnicity and social deprivation. METHODS: Using data from the New Zealand cancer registry, a retrospective review was undertaken of incident cases with a histological diagnosis of invasive squamous cell carcinoma (SCC) in the oral cavity or oropharynx. RESULTS: During the period 1981-2010, rates of oropharyngeal cancers (OPC) and oral cavity cancers (OCC) were higher among males and increased with age. The rapid rise in male OPCs was observed in those aged 40-49, 50-59, 60-69 and >/=70 years old. Overall and by gender, Maori had higher OPC rates but lower OCC rates than European/other ethnicities, whereas the inverse was apparent among Pacific Peoples. An upward trend in OPC and OCC rates with increasing deprivation was observed both overall and by gender. CONCLUSIONS: The recent rapid rise in male oropharyngeal SCCs occurred primarily among those aged >/=40 years old. IMPLICATIONS: Given oropharyngeal SCCs are more strongly associated with human papillomaviruses (HPV) than OCCs, OPC prevention may be enhanced through HPV vaccination and public health awareness. Clinically, as HPV-related OPCs have a better prognosis and response to radiotherapy, an improvement in survival rates can be predicted.