|Cancer single map||Cancer double map|
The cancer incidence domain of the Atlas of Healthcare Variation gives clinicians, patients and providers an overview of the crude and age-standardised incidence rates both overall and for the five most common cancers in New Zealand, by district health board (DHB). The intention of this domain is to set the scene for future atlases to undertake a more detailed exploration of the diagnosis and management of certain cancer types.
Cancer is a leading cause of morbidity and mortality in New Zealand, accounting for nearly one third of all deaths. Despite a decline in cancer mortality and an increase in cancer survival over time, it remains an important cause of preventable mortality and illness alongside cardiovascular disease. Smoking, nutrition, obesity, alcohol and lack of exercise are significant risk factors. For Māori and people living in socioeconomically deprived areas, the burden of cancer is much higher than for the general population.
While the overall risk of developing cancer in New Zealand is expected to stabilise or decline over the next decade, New Zealand has an increasing number of people who are developing cancer, mainly because of population growth and ageing.
Data for this Atlas domain were drawn from the Ministry of Health’s New Zealand Cancer Registry (NZCR), which collects registration information about each tumour, as well as key demographic information. The registry includes all malignant cancer apart from superficial cancers of the skin (basal cell and squamous cell cancers of the skin). Melanoma is included. Read the cancer incidence atlas methodology.
Technically what are being presented are ‘registration’ rates – the rate cancers are being recorded in the cancer registry. Registration is a statutory obligation pursuant to the Cancer Registry Act 1993.
Incidence rates are presented for all cancers and then the five most common cancers separately. In the period 2008–2012 these were: female breast cancer, colorectal cancer, lung cancer, melanoma and prostate cancer (males only). These five cancers accounted for 63 percent of registrations. Data are presented for five years combined and the analyses by year are presented as three year rolling averages to allow for statistical robustness.
The incidence rates presented here are both crude and age-standardised rates (ASR). Age-standardisation adjusts rates to account for the age structure of the DHB population. This is important because cancer rates increase significantly with age. This means DHBs that have a population that is older than average will have higher rates of cancer than those with a younger population. Age-standardised data allows us to tell whether variation between DHBs is the result of age structure or not. In contrast, the crude rates show actual cancer incidence rates by DHB. These rates give information to enable regional population-level planning for cancer prevention and control.
For additional analysis please visit: http://www.health.govt.nz/publication/cancer-new-registrations-and-deaths-2011.
a) All cancers
The table below shows the total number of cancer registrations over five years (2008–2012) by cancer type and by sex.
|Table one: The number of commonly registered cancers, by sex, 2008–2012|
|Cancer||Males (count)||Cancer||Females (count)|
|Colorectum and anus||7,629||Colorectum and anus||7,075|
b) Female breast cancer
c) Colorectal cancer
d) Lung cancer
f) Prostate cancer
These data show that over the period studied the crude incidence rates of all cancers and the five most common cancers varied up to two and half times by DHB. Age standardisation shows that age can explain many of these differences, but not all.
The demography Atlas presents by DHB life expectancy rates, ethnic composition, age bands and deprivation which might be useful in interpreting these cancer incidence data: www.hqsc.govt.nz/atlas/demography.
Presenting these data provide the context for future cancer-specific analyses exploring whether there is variation in the diagnosis and treatment.
Ministry of Health. 2014. Cancer: New Registrations and Deaths 2011. Wellington: Ministry of Health. http://www.health.govt.nz/publication/cancer-new-registrations-and-deaths-2011.
Ministry of Health. 2013. Health Loss in New Zealand: A report from the New Zealand Burden of Diseases, Injuries and Risk Factors Study, 2006–2016. Wellington: Ministry of Health. http://www.health.govt.nz/publication/health-loss-new-zealand-report-new-zealand-burden-diseases-injuries-and-risk-factors-study-2006-2016 .
Ministry of Health. 2014. Webtables containing summarised cancer information for selected cancers, 2011-2013. http://www.health.govt.nz/publication/selected-cancers-2011-2012-2013.
National Institute of Health and Care Excellence. 2015. Suspected cancer: recognition and referral. http://www.nice.org.uk/guidance/ng12/evidence/full-guidance-65700685.
As we are starting to explore cancer within the Atlas of Healthcare Variation, we would welcome feedback and suggestions.