Updated: 01 Sep 2009

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Introduction

Melanoma is one of New Zealand's most common cancers, but if diagnosed in time, treatment is very successful.

If you have any concerns about a mole, you need to get it checked. We find out what's involved in getting your moles mapped, and look at melanoma risk factors and warning signs.

Warning signs

Melanoma is New Zealand's fourth most common cancer, accounting for about 2000 new cases and more than 200 deaths each year. Provisional data for 2006 list 2183 new melanoma cases and 287 deaths. It’s the most common cancer in New Zealanders aged between 20 and 39.

A mole may be harmless. But it could be a melanoma. Look for any of these warning signs:

• Asymmetry – the mole has a lopsided shape.
• Border irregularity – its edges are uneven.
• Colour variation – its colour is patchy.
• Diameter – the mole is more than 6mm across.
• Evolution – it’s changed its shape or has got bigger. 

Who’s at risk?

The risk factors for melanoma are:

• aged 50 or older
• previous skin cancer
• a parent or sibling who has had a melanoma
• more than 50 normal moles or more than 5 large or unusual moles
• fair skin that burns easily
• a history of sunburns.

Having any one of these risk factors means you should check your skin - or have it checked by your partner, GP or dermatologist - on a regular basis.

Non-melanoma skin cancers
Everyone should be aware of non-melanoma skin cancers. Although they’re usually less dangerous than melanoma they’re much more common.

A slowly growing patch that bleeds or ulcerates easily may be a basal cell cancer. An enlarging and tender scaly lump could be a squamous cell cancer. See your GP or dermatologist if you have either of these. 

More information

• New Zealand Dermatological Society: www.dermnet.org.nz
• Cancer Society of New Zealand: www.cancernz.org.nz 0800 CANCER (0800 226 237)
• Melanoma Foundation of New Zealand: www.melanoma.org.nz

Getting it checked

If you have any concerns about a mole - especially a mole that has just appeared or has changed - see your GP or a dermatologist. (They can also check for non-melanoma skin cancers and for pre-cancerous spots known as “solar keratoses”.)

It’s difficult to tell with the naked eye whether a mole is harmless or not. Your GP may decide to cut the mole out or refer you to a dermatologist. A dermoscope - a magnifying device - may be used to examine the mole’s structure, to help determine whether it is a melanoma.

If the mole is possibly cancerous, your GP or dermatologist will cut it out or do a biopsy and send the tissue sample to a laboratory for diagnosis. A confirmation of melanoma may mean further surgery: this will take a wider area of skin and underlying tissue, to make sure no melanoma cells are left in the area.

People at high risk of melanoma (see Who’s at risk?) may have to return for follow-up checks as often as every six months.

Making certain

Most moles are harmless and don’t need to be removed - unless you feel the mole is unsightly or gets in the way of your clothing, comb or razor.

A biopsy is the most accurate way of finding whether a mole is harmless or not. But biopsies are costly and they leave a scar; they also place a strain on health services. The more experienced the practitioner, the less likely you are to have an unnecessary biopsy.
 

Mole mapping

"Mapping" is a general term for programmes that monitor changes in suspicious moles and detect new ones. It’s of greatest benefit to people who have a high risk of melanoma.

A number of specialised clinics offer programmes such as MoleMap, MoleCheck, MoleSpec, MoleTrac and MoleMate. Your dermatologist may also use a mapping programme.

The tools of mole mapping are sequential imaging and total body photography.

• Sequential imaging tracks changes in individual moles. Suspicious moles are photographed and their dermoscopic images stored on a computer to form a baseline for follow-up checks. But the effectiveness of this system depends on the technician’s ability to select the right moles to photograph. You may be given prints or digital copies on a CD so you can carry out your own checks at home.
• Total body photography is used for people with a lot of moles. All existing moles are captured so new arrivals can be identified.

The mapping’s just a tool. It’s important that its images are analysed by an experienced professional – preferably a dermatologist. Your doctor may use an automated diagnosis system to help decide whether a mole needs to be removed or not. These compare your moles with a large database of melanomas and benign moles.

We tried it

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We sent a volunteer to have her moles mapped.

At the start of the hour-long session the technician discussed our volunteer’s melanoma risk. Jane (not her real name) has a family history of skin cancer, spent time in the sun as a child, has fair skin and has a lot of moles.

The whole of her body was photographed, a section at a time. More than a dozen photos were taken – of each arm and leg, her torso and her face, even the soles of her feet. Jane felt perfectly comfortable as she kept on her underwear and wore a gown for much of the session.

The technician then examined Jane’s skin with a dermoscope, looking for moles that might be a melanoma and for signs of other skin cancers. More than 30 moles were photographed and referenced back to a body photograph so they could be identified in follow-up visits.

The photographs and records are stored on a secure server where they can be analysed by a dermatologist. Jane received a report (“all clear”) within a week and her doctor received one as well. In a year she will receive a reminder for a follow-up visit.

Jane’s verdict
"The session cost more than $200 but it was worth the expense. I felt I received a very thorough examination. As most of my moles are on my back and shoulders, I can’t easily keep an eye on them myself and notice when anything has changed."
 

Specialist clinics

You can go to a specialist clinic without a referral from a doctor, but there are some questions you should ask first.

• What services are offered? Will you be seen by a dermatologist? Do you want sequential imaging or total body photography? Will the clinic check your skin for other skin cancers too?
• Who provides the services? Images are usually taken by a technician – what experience and training have they had? How are the images analysed – by an experienced professional (preferably a dermatologist) or through a computer programme?
• How much will it cost? Find out about costs beyond the initial consultation. Will there be a charge for storing images, or for copies to help with your own skin checks? What’s the fee for follow-up visits?
• What happens next? If a mole looks suspicious, will a biopsy be taken or will you be referred back to your GP (and incur extra costs)? Will a biopsy be sent to the laboratory for diagnosis? Will a record of your diagnosis and treatment be sent to your GP and also to you? Will you get a reminder of when it’s time for your next visit?

The clinic should also give you:

• information about skin cancer and sun protection
• advice on how to check your skin and on the changes to look for.
    

Report by Bev Frederikson.