Skin cancer is the most common of all cancers, afflicting perhaps two-thirds of white-skinned New Zealanders and many others throughout the world. Skin cancer is also the easiest cancer to cure if diagnosed and treated early. However, if the skin cancer is allowed to progress, it can result in disfigurement and even death.
Who should do a self-skin examination?
Everyone should! It is particularly important for people with the following characteristics to do so.
- White skin
- Aged over 40
- Previous melanoma
- Previous basal cell carcinoma or squamous cell carcinoma
- Many moles or freckles
- Actinic keratoses (scaly spots on sun-exposed sites)
- Outdoor work or recreation
- Many sunburns or visits to solaria
- Syndromes that increase the risk of skin cancer
- Taking immune suppressive medications, eg organ transplant patients
Skin self-examination can be supplemented by clinical examination by a dermatologist or a general practitioner. In many areas of New Zealand and elsewhere, sophisticated photographic screening systems have been established (mole mapping). Whole-body digital photographs are recorded, together with close-up and dermatoscopic pictures of lesions of concern. These are examined by an expert in dermatoscopy. Whole-body images reveal new lesions, and digital dermatoscopic surveillance at intervals can reveal subtle changes that may indicate the development of melanoma within an existing lesion.
When should I examine my skin?
Skin self-examination should be done often enough to become a habit, but not so often as to feel like a bother. For most people an interval of one to three months is ideal. Photographic screening is generally performed annually.
After the first few times, self-examination should take no longer than a few minutes. You will need help in seeing your back, so enrol your partner or a good friend to help.
What do skin cancers look like?
There are three main types of skin cancer:
There are many other types of skin cancer, but these are rare.
Because each has many different appearances, it is important to know the early warning signs. Look especially for change of any kind. Do not ignore a suspicious spot simply because it does not hurt. Skin cancers may be painless, but dangerous all the same. If you notice one or more of the warning signs, see a doctor right away.
What are the warning signs of skin cancer?
A skin growth that increases in size and appears pearly, translucent, tan brown, black, or multicoloured.
A melanocytic naevus (mole), birthmark or any skin spot that:
- Changes in colour.
- Increases in size or thickness
- Changes in texture
- Is irregular in outline
- Is bigger than 6 mm, the size of a pencil eraser
A spot or sore that:
- Itches or hurts
- Crusts or scabs
- Ulcerates or bleeds
- Fails to heal within three weeks
In other words, be concerned by a lesion that looks different from your other skin spots. This is sometimes called an ugly duckling—in New Zealand, we often use another term, a black sheep. The good news is that most ugly ducklings turn out to be harmless. Benign melanocytic naevus (moles), freckles and seborrhoeic keratoses can be hard to distinguish from skin cancers at times.
What parts of my skin should I check?
- The self-skin examination should start with the head and end with the feet.
- The self-skin examination should include the scalp, face, neck, beneath facial hair and trunk.
- On the upper part of the body, the self-skin examination should include the armpits, hands, finger webs and nail beds.
- A mirror should be used to examine the back and skin between the buttocks.
- On the legs, it should include toe webs, toenail beds and soles of the feet.
- Print the body map below to mark the site of any lesions you're concerned about.
Self skin examination
When should I see my doctor?
Show your doctor anything that concerns you—the earlier the better. Ask for a full skin check. Like most cancers, the earlier you detect skin cancer the simpler the treatment. Because skin cancer is on the outside of your body it is the easiest cancer to see. So even though skin cancer is the commonest cancer, it is also the most curable. Keep your eyes open for any changes, and take a few sensible precautions.