Skin cancer is the uncontrolled growth of abnormal skin cells. It is the most common cancer affecting New Zealanders; however, it is largely preventable. If you protect your skin from the sun throughout your life, you will greatly reduce your risk of skin cancer.
On this page, you can find the following information:
Melanoma is the most serious skin cancer and is the cause of more than 2 in 3 skin cancer deaths.
Over 90% of all skin cancer is due to excess sun exposure.
Protect your skin from the sun by being SunSmart and remembering to 'slip, slop, slap and wrap'.
Do regular skin checks so that you get to know your skin and notice any changes.
When found early, most skin cancers can be successfully treated. See a doctor if you notice dark, pigmented moles or skin spots, or ones that are crusted or bleeding.
What causes skin cancer?
Most skin cancer is caused by ultraviolet (UV) light damaging your skin’s cells. The main source of UV light is the sun. Artificial sources of UV light, such as sunlamps or tanning beds, can also increase your risk of skin cancer.
Protecting your skin from the sun (and not using sunbeds) combined with regular skin checks, is the best way to prevent skin cancer.
Who is at risk of skin cancer?
People of all ages and skin colours can be diagnosed with skin cancer but those at a higher risk are people who have:
fair, light-coloured skin
skin that burns easily
had one or more severe sunburn, especially as a child
spent a lot of time outdoors unprotected from the sun
used sunbeds, particularly at a young age
a family history of skin cancer
a large number of moles or large, irregularly shaped and unevenly coloured moles.
New Zealand’s skin cancer rates are among the highest in the world
Our high skin cancer rates are due to:
high levels of UV radiation during daylight-saving months
low ozone levels
our outdoor lifestyle
a high proportion of people with fair skin.
What are the signs of skin cancer?
Most of us have freckles, moles or other spots on our skin. This is normal. However, you should see your doctor or skin specialist if you have a freckle, mole or spot that:
is new or changing
does not heal
looks different from others around it
has changed in size, thickness, shape, colour
has started to bleed.
When should I get my skin checked?
Have your skin checked by a doctor immediately if you notice any of the changes described above.
Your GP can also perform a skin check in combination with a general health check-up. If you are at higher risk of skin cancer, you may need regular skin checks as advised by your doctor.
All New Zealanders should become familiar with their skin by doing regular skin self-checks (preferably once every 3 months). Being familiar with your skin means you will be more likely to notice any suspicious lumps or spots as soon as they develop, and at a stage when they can be successfully treated.
Skin checks are particularly important if you are over 50, have a family history of skin cancer or have had any bad sunburn as a child.
Skin cancer is largely preventable. Over 90% of all skin cancer cases are caused by excess sun exposure. If you protect your skin and avoid sunburn throughout your life, you will greatly reduce your risk of skin cancer.
Be SunSmart in the months between September and April, especially between the hours of 10am–4pm when UV radiation levels are very high. Don't just use protection on hot and sunny days; UV can still be damaging on cool, cloudy days.
In winter it is also important to be SunSmart at high altitudes and around snow or water.
Steps to being SunSmart:
Slip –into shade where possible.
Slip –on some sun protective clothing, for example, a shirt with a collar and long sleeves, and trousers or long-legged shorts.
Slop –on broad-spectrum sunscreen that has a sun protection factor (SPF) of at least 30. Apply 20 minutes before you go outside, and re-apply every two hours, especially if you are swimming or sweating.
Slap –on a hat that protects your face, head, neck and ears.
Wrap –on some close-fitting sunglasses.
What if I have had a lot of sun exposure in my life?
Before the dangers of sun exposure were fully understood, many New Zealanders spent a lot of time outdoors without sun protection or used tanning beds. If you are worried you may have increased your risk of skin cancer in this way, the key is to prevent further skin damage and to have regular skin checks with your doctor. If you notice any darker, growing or changing moles, get them checked straight away.
Ways to protect your skin
Avoid outdoor activities when the sun is strongest – between 10 am and 4 pm during September to April in New Zealand
Wear sunscreen and lip balm daily that offer SPF 30 or higher sun protection.
Use sunscreen that offers broad-spectrum (UVA/UVB) protection and is water resistant.
Apply the sunscreen and lip balm to dry skin 15 minutes before going outdoors.
Apply the sunscreen to every part of your body that will not be covered by clothing. Reapply it every two hours if you are swimming or sweating.
Whenever possible, wear a wide-brimmed hat, long sleeves and long pants.
Wear sunglasses to protect the skin around your eyes.
Avoid getting a tan and never use a tanning bed or sun lamp.
Skin cancers are classified into two groups –melanomaand non-melanoma.
Melanoma is a type of cancer that develops in the skin’s pigment cells (melanocytes). Melanoma is less common but more serious than non-melanoma skin cancers.
Non-melanoma skin cancer refers to a group of cancers that slowly develop in the upper layers of your skin. The two most common types of non-melanoma skin cancer are basal cell carcinoma and squamous cell carcinoma.
Usually appears as a changed or new freckle or mole. Often they have an unusual shape or colour, or a variety of colours, but sometimes may not be coloured.
Some types may itch, bleed or weep.
They may become raised quickly and catch on clothing.
If left untreated, melanoma can spread rapidly to other parts of your body and become life-threatening.
Solar keratoses or sunspots are not a type of skin cancer. However, they are a sign of sun damage to your skin and a warning that you may be prone to skin cancer. Solar keratoses are flat, red or sometimes brown, scaly areas, which may sting if scratched. They are very common in fair-skinned people over 40 who have spent a lot of time outdoors.
How to do a skin cancer check
Checking your skin regularly (including skin not normally exposed to the sun) will help you get to know how your skin normally looks so you can be aware of any changes. This is especially important as you get older, particularly if you are over the age of 50.
Make sure you check your entire body, as skin cancers can sometimes occur on parts of your body that are not exposed to the sun.
Take the following steps to check your skin:
Use a hand-held mirror or ask for help from someone else to check hard-to-see areas, such as your back and neck.
Check underneath your armpits, inner legs, ears, eyelids, hands and feet.
Use a comb to move sections of hair aside and check your scalp.
If you notice any skin changes, see your doctor.
Skin check apps
There are a variety of apps for smartphones and mobile devices that allow you to take photos of your skin, and track and monitor changes to your skin lesions. These may be useful in learning more about melanoma and may provide a tool to capture images of skin lesions such as moles. Read more about skin check apps.
Most skin cancers are treated surgically (cutting out the cancer). This is done using a localanaestheticto numb your skin. Surgical techniques include:
This is where a skin lesion is completely cut out. It is impossible to fully excise a skin lesion without leaving some scarring. The most common type of excision is an elliptical excision. This is designed so that the scarruns parallel with your skin creases, making it less visible.
There will also be a margin of normal surrounding tissue cut out. How wide the margin is depends on the type of cancer and how deep or aggressive it is. The tissue cut out is then sent to the laboratory for analysis by a pathologist.
After the pathologist has confirmed the lesion is a skin cancer, a wider incision (further surgery to remove more of the surrounding skin from the wound) is sometimes needed.
If a large amount of skin needs to be removed, or it is in a tricky area, a skin graft may be needed to cover the area.
This is a specialised, more intensive form of surgery for skin cancer, also called Mohs micrographic surgery (MMS). It uses a microscope to help check that the deep roots of the cancer have been removed.
It can be used to remove large, deep or recurring cancers. It is also often used for cancers in areas that are difficult to treat by other surgical methods, such as cancers near your eye.
This is the use of extreme cold (such as liquid nitrogen) to treat pre-cancerous skin conditions (eg, solar keratoses) and some small skin cancers. Liquid nitrogen is applied to the tumour to freeze and kill the abnormal cells. Some pain and redness may occur afterwards, and a blister may develop on the treated area. There may be a white mark or scar from the treatment.
Topical therapy means applying a cream to the skin cancer.
Fluorouracil cream can be applied directly to your skin once or twice a day for several weeks. The area will become red, then there will be blistering, peeling or cracking. The skin settles and heals once the treatment has finished.
Imiquimod can be used to treat pre-cancerous lesions and superficial basal cell carcenomas (BCCs). It is known as an immunomodifier because it stimulates your immune system to recognise and destroy cancer cells. It is easy to use as it is a cream applied to your skin, usually several times a week, for a period of some weeks.
It tends to cause inflammation and redness, itching and burning on the treated area. Some people may also experience flu-like symptoms such as headaches and fatigue during treatment. Side effects are generally mild, but if they are severe, stop using the cream and see your doctor.
This is a two-step process using a light source (such as a laser) and a photsensitising cream. In the first step, the skin area with the cancer is scraped lightly and a cream is applied to make the cancer cells sensitive to light.
In the second step, a few hours later, the area is exposed to a light source, so the cancer cells can be destroyed. If you feel any pain, you will be given a local anaesthetic.
Radiotherapy is an option for hard-to-treat skin cancer, such as cancer on your eyelids or nose, or if you are medically unfit for any type of surgery. Radiation treatment uses high-energy x-rays to destroy cancer cells.
Treatments usually occur for a short time daily or weekly. The area may become red and sore, and there may be changes in skin colour and/or texture in the long term.
Laser surgery is also used for people who have lesions on sensitive locations, such as your eyelids or face, as well as for people who have a weakened immune system and so surgery is not a good option.
Assess the likelihood of melanoma being present then provisionally identify the type of lesion.
Surgical excision with histology is the first-line treatment for all skin cancer. It has the highest cure rate among available treatments.
Referral, according to local guidelines, to a General Practitioner with a Special Interest (GPSI) in skin lesions, a Dermatologist, a Plastic Surgeon or an ENT Surgeon may be appropriate for patients with large lesions or lesions with an aggressive growth pattern.
Patients with superficial basal cell carcinoma or intraepidermal carcinoma (squamous cell carcinoma in situ) may be safely managed with cryotherapy or topical treatments, i.e. fluorouracil or imiquimod creams, when excision is not appropriate because of the location of the lesion or due to cosmetic considerations.
Topical treatments should not be considered if the diagnosis is uncertain.
Red-flags: Is this melanoma?
Look for features of a melanoma using the ABCDE ruleor the seven-point checklist.
The ABCDE rule
Colour variation. Note: Black is not essential and may not be present in some melanomas, ie, nodular or amelanotic melanoma.
Diameter > 6 mm. However, melanoma can be diagnosed when less than this diameter.
Evolution and/or elevation, eg, lesions may enlarge and a flat lesion may become raised in a matter of a few weeks.
Change in size of previous lesion or obvious growth of a new lesion
Irregular colour with a variety of shades of brown and black
Diameter > 6 mm
Oozing, crusting or bleeding
Change in sensation
To help with identification DermNet NZ for images of:
Management of non-melanoma skin cancer in primary care
In the following video, Dr Diana North, Goodfellow GP Advisor talks with Dr Marcus Platts-Mills, Dermatology and Skin Cancer Surgery specialist, about the management of non-melanoma skin cancer in primary care.
(Goodfellow Unit, NZ, 2017)
PHARMAC Seminar series
Videos from the one-day PHARMAC seminar on dermatoscopy held in Wellington, New Zealand, on May 4th, 2016, by Prof Bruce Arroll & Prof Amanda Oakley.