Skin Cancer
There are two main types of fully developed skin cancer, which both occur in the outer layer of the skin (the epidermis).
- Cancer of the skin cells, called squamous cell cancer (SCC).
- Cancer of the pigment cells, called melanoma.
Squamous cell cancer of the skin can grow slowly or rapidly, and is usually seen as a firm hard lump in the skin. Some have hard dry skin on the surface. Others have no skin covering in the centre, that is they are ulcerated, and may ooze fluid
Melanoma is usually brown to black, often a mixture of the two, but may contain patches of grey or red. It can develop from a previously harmless mole, or as a new growth in normal looking skin. A wavy, scalloped or notched edge is common.
Both these cancers can spread to other parts of the body. Early diagnosis and treatment are important.
Basal cell cancer (BCC) arises from the bottom layer of the epidermis. It is quite common. Although technically the cells are cancerous, they do not spread in a dangerous manner. The growth rate is usually slow. BCCs take different forms, for example a thickened patch, a pearly looking lump, or a crater shaped swelling.
Precancerous conditions in the skin are commoner than fully developed cancers and have sometimes been present for many years before the cancer begins to grow.
Solar (or actinic) keratosis which occurs as roughening and later hardening of the outer layer of the skin. There is often patchy redness. It occurs in areas which have had a gradual build-up of sun exposure, not necessarily sunburn, over the person’s lifetime - commonly the face, and bald scalps. Solar keratosis occasionally develops into squamous cell cancer; thickening or hardening are warning signs. Treatment will always involve avoidance of further sun damage, and might also include freezing or treatment with special creams prescribed by the doctor.
What to do Anyone who suspects they might have one of these cancers or a precancerous condition should see their doctor promptly. If squamous cell cancer or melanoma is suspected, the doctor will arrange for urgent treatment, often by arranging a visit to a specialist clinic. If basal cell cancer or a precancerous condition is suspected, treatment does not need to be so urgent, but might involve referral to a specialist clinic.
Skin cancer and sunlight
Sunlight is the main cause of skin cancer. This means not only sunburn, but also the gradual build-up of sun exposure over many years.
Sunscreens (or sun barrier creams) have greatly improved in recent years. They are effective when used properly and have become less messy. The sun protection factor (SPF) is the fraction of the more damaging rays (ultraviolet B) which can get through the layer of cream: for example, if the cream lets through a fifteenth of the UVB it is called Factor 15. You should aim for Factor 15 or higher - many of these are invisible on the skin and pleasant to use. Increasingly, ladies’ cosmetics and moisturising creams contain sunscreens too.
Allan Highet, June 2004