Comparison of oropharyngeal and oral cavity squamous cell cancer incidence and trends in New Zealand and Queensland, Australia.
BACKGROUND
Increases in the incidence of squamous cell oropharyngeal cancer (OPC) have been reported from some countries, but have not been assessed in Australia or New Zealand. This study examines trends for squamous cell OPC and squamous cell oral cavity cancer (OCC) in two similarly sized populations, New Zealand and Queensland, Australia.


METHODS
Incidence data for 1982-2010 were obtained from the respective population-based cancer registries for squamous cell OPC and OCC, by subsite, sex, and age. Time trends and annual percentage changes (APCs) were assessed by joinpoint regression.


RESULTS
The incidence rates of squamous cell OPC in males in New Zealand since 2005 and Queensland since 2006 have increased rapidly, with APCs of 11.9% and 10.6% respectively. The trends were greatest at ages 50-69 and followed more gradual increases previously. In females, rates increased by 2.1% per year in New Zealand from 1982, but by only 0.9% (not significant) in Queensland. In contrast, incidence rates for OCC decreased by 1.2% per year in males in Queensland since 1982, but remained stable for females in Queensland and for both sexes in New Zealand. Overall, incidence rates for both OCC and OPC were substantially higher in Queensland than in New Zealand. In males in both areas, OPC incidence is now higher than that of OCC.


CONCLUSIONS
Incidence rates of squamous cell OPC have increased rapidly in men, while rates of OCC have been stable or reducing, showing distinct etiologies. This has both clinical and public health importance, including implications for the extension of human papilloma virus (HPV) vaccination to males.
School of Population Health, University of Auckland, Auckland, New Zealand. Electronic address: mark.elwood@auckland.ac.nz.
J Mark
JM
Elwood
Cancer Council Queensland, Brisbane, Australia.
Danny R
DR
Youlden
School of Population Health, University of Auckland, Auckland, New Zealand.
Carol
C
Chelimo
School of Population Health, University of Auckland, Auckland, New Zealand.
Sally J
SJ
Ioannides
Cancer Council Queensland, Brisbane, Australia; School of Public Health, Queensland University of Technology, Brisbane, Australia; Griffith Health Institute, Griffith University, Gold Coast, Australia.
Peter D
PD
Baade
D000328:Adult; D017677:Age Distribution; D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000453:epidemiology* / Q000473:pathology; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000453:epidemiology* / Q000473:pathology; D009520:New Zealand / Q000453:epidemiology; D009959:Oropharyngeal Neoplasms / Q000453:epidemiology* / Q000473:pathology; D011793:Queensland / Q000453:epidemiology; D012042:Registries; D012044:Regression Analysis; D017678:Sex Distribution
Epidemiology; HPV; Incidence; Oral cancer; Oropharyngeal cancer; Trends