Melanoma is a type of cancer that occurs in your skin. It often appears as a new spot on normal skin or develops from an existing mole.
Melanoma is the most dangerous type of skin cancer. If left untreated, it can spread rapidly to other parts of your body and become life-threatening.
New Zealand has one of the highest rates of melanoma in the world.
It’s important to have regular skin checks by your doctor and if you notice any darker, growing or changing moles, to get them checked straight away.
If melanoma is recognised and treated early enough, it is almost always curable.
What is melanoma?
Melanoma is a type of cancer that begins in your skin's pigment cells, known as melanocytes.
Melanocytes produce a brown-coloured pigment called melanin. This gives skin its colour. When melanocyte cells group together in the skin they can form a mole.
Most moles are safe. However, sometimes the melanocytes in them begin to grow and divide in an uncontrolled way and form a melanoma.
Melanoma is the most serious type of skin cancer and it can spread quickly. It is treatable if it is caught early, but if the cancer spreads to other parts of your body, it can be life-threatening.
What causes melanoma?
Most melanomas are caused by overexposure to sunlight, or more specifically UV radiation. Each time your unprotected skin is exposed to UV radiation from the sun or other sources, such as sunbeds, the UV radiation causes changes to the structure of the melanocytes.
This causes your skin to become permanently damaged. The damage worsens with more UV radiation.
Where do melanomas occur?
Melanoma occurs most commonly on parts of your body that have been sunburned. However, it can appear in skin anywhere on your body – even on parts that aren’t usually exposed to the sun, such as the soles of your feet or under your toenails.
What do melanomas look like?
appear as a new spot
be an existing spot, freckle or mole that changes colour, size or shape
If you are worried that you have a melanoma, see your doctor or a qualified skin check provider for an examination. If they think the mole or lesion is suspicious, they will take a small sample, known as a biopsy.
A biopsy is a simple procedure in which a part or all of the lesion is surgically removed and sent to the lab for testing. This can be done at your doctors or you might be referred to a dermatologist or surgeon.
The results will be sent back to your doctor, who will let you know if melanoma or another type of skin cancer was found. If the mole or lesion was found to be melanoma, your doctor will discuss with you what stage (how advanced) it is and the treatment required.
Stage 0 – (melanoma in situ) abnormal cells found in the epidermis (outer layer of your skin).
Stage 1 – the melanoma is not more than 2mm thick.
Stage 2 – the melanoma is more than 2 to 4mm thick with no spread to your lymph vessels or lymph nodes.
Stage 3 – any thickness of melanoma that has spread to your lymph vessels or lymph nodes.
Stage 4 – the melanoma has spread to other parts of your body.
If a melanoma is caught early, it can normally be treated successfully. If it has spread to other parts of your body, it can be harder to treat.
Credits: Health Navigator Editorial Team.
Last reviewed: 06 Dec 2017
Skin check or melanoma detection apps
If found and treated early, most melanomas are curable. The key is to have any skin changes or moles checked straight away.
There are a variety of smart phone apps that are marketed for skin checking and early melanoma detection. They allow you to take photos of your skin, and track and monitor changes to your skin lesions.
Be aware that not all skin checking apps are reliable. Apps that give you a risk assessment of your skin changes by enabling you to send images to a skin specialist for analysis are far more reliable and a safer option than apps that use automated computerised analysis algorithms to give you an analysis of skin cancer risk.
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 i.e., nodular or amelanotic melanoma.
Diameter > 6 mm. However, melanoma can be diagnosed when less than this diameter.
Evolution and/or elevation e.g., lesions may enlarge and a flat lesion may become raised in a matter of a few weeks
Seven point check List
Change in size of previous lesion or obvious growth of a new lesion
Irregular colour with a variety of shades of brown and black
Management of non-melanoma skin cancer in primary care
In thr 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.
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.