Skin cancer is the most common cancer in New Zealand. New skin cancers total about 67,000 per year, compared to a total of 16 000 for all other types of cancer. Our skin cancer rates are the highest in the world. In fact, the incidence of melanoma in New Zealand and Australia is around four times higher than in Canada, the US and the UK.
It is difficult to know exactly how many people in New Zealand develop basal cell or squamous cell carcinomas, as doctors aren’t required to report these figures. However, 45 000 cases per year are confirmed by laboratory tests, and it is thought that there may be up to 25 000 more cases that are treated immediately, but are not sent off to be confirmed by a laboratory. Research suggests that two in three New Zealanders will develop a non-melanoma skin cancer during their lifetime.
Melanoma cases are reported. In 2011, there were 2204 cases of melanoma in New Zealand. Malignant melanomas more frequently result in death (359 deaths in 2011). Just like other cancers, melanoma is more common in older people, but it is not just an ‘old person’s disease’ – in fact, it is one of the most common types of cancer for 25–44 year olds (15 male and 11 female deaths in 2011). Melanoma is the third most commonly registered cancer in young women and the fourth in young men aged 0-24 years.
Why are our statistics so high?
Over 90% of skin cancers are due to excess UV exposure in high UV environments like New Zealand. Non-malignant skin cancers are generally found on the exposed parts of the body (such as the face and forearms), and long-term frequent UV exposure is thought to be a predominant cause.
Malignant melanoma risk is linked with an individual’s UV exposure patterns as well as genetic characteristics, like fair skin. Light skin type, a large number of moles and excess sun exposure (particularly episodes of sunburn), especially in childhood and adolescence, are the major predictors of skin cancer risk.
Some reasons for New Zealand’s particularly high skin cancer statistics:
- The strength of the UV radiation that New Zealand receives – our UV levels are 40% higher during summer than at corresponding latitudes in the northern hemisphere (NIWA research).
- The low ozone levels – the ozone layer absorbs a good deal of UVB ultraviolet light from the Sun. Any decrease in the ozone layer (such as the ‘ozone hole’ over Antarctica) is expected to increase surface UVB levels. Excessive UVB exposure causes skin cancers such as basal cell carcinomas and squamous cell carcinomas. However, UVA, which is linked to melanoma, is not absorbed by ozone.
- The significant proportion of the population that has skin types which burn easily (due to our genetic heritage).
- Our more outdoor lifestyle and tendency to ‘seek the sun’.
What is the cost of treatment?
Treatment of skin cancer is an expensive cost for our country (through taxes). It is estimated that skin cancer costs New Zealand over $33 million per year, making it one of the most expensive cancers for the New Zealand health system. The greatest cost, though, is the emotional cost to the skin cancer patient, their friends and family.
The SunSmart Schools website is designed for students, teachers, schools and parents. It has information about UV, shade, hats, sunscreen, skin cancer and sun protection, as well as cross-curricula resources for teachers at levels 1 to 4 of the New Zealand Curriculum.
New research indicates that New Zealand has now overtaken Australia as the world leader in invasive melanoma rates.