These data are reported using the age-standardised rate (ASR) per 100,000 population, where our population profile is standardised to the World Health Organization world standard population. Using age-standardised rates allows comparisons to be made between different datasets or years. It means any differences in rates over time will be due to factors other than changes in the age structure of the population. This is important because cancer is a disease that predominantly affects the elderly. Because our population is ageing, we can expect an increase in cancer numbers.
Limitations of the data
Increases in melanoma rates may be due to several factors, including more people seeking diagnosis of unusual skin conditions because they have greater awareness of the risks and repercussions of melanoma.
2014–15 data are provisional and subject to change.
Changes to data collection/processing
The passing of the Cancer Registry Act 1993 and Cancer Regulations 1994 led to significant improvements in data quality and coverage (Ministry of Health, 2013). A sharp increase in registrations after 1993 is likely to have been related to these legislative and regulatory changes.