In most Caucasian populations, skin cancer is the most common human malignancy. Irradiation from the sun is the dominant cause of nearly all forms of skin cancer.
Skin cancers can be broadly categorised as melanoma and non-melanoma skin cancer Melanomas are less common than the non-melanoma skin cancers, but they are more aggressive and fatal. Non-melanoma skin cancer is much more common, but can usually be cured.
Melanoma is a form of cancer that starts in skin cells called melanocytes. Melanocytes make the dark pigment called melanin that makes the skin darker. A melanoma is best diagnosed and treated early. If not, it could grow deeper into the skin and spread to other parts of the body.
Melanoma affects young people more often than older people. Some people are more likely than others to get melanoma. Having lots of moles (more than 50), especially ones with jagged edges, makes it more likely.
Other things that increase the chance of getting this type of cancer include having relatives who have had melanoma, having had bad sunburn as a child, and having freckles, or a fair skin.
What are the warning signs?
The two main warning signs of melanoma are changes in a mole that you already have, or a new mole or dark spot appearing on your skin. See your doctor if you find a mole that has changed in shape, size or colour, or that feels different (rougher or scalier than before), hurts, itches, or bleeds.
Basal cell cancer and Squamous cell cancer
These are non-melanoma skin cancers. Basal cell cancer (BCC) starts in the base of the skin. It is the most common human cancer. Squamous cell cancer (SCC) starts in the top layer of the skin, just under the surface. If BCC isn’t treated it can damage the tissues nearby, and rarely spread to other parts of the body. Untreated SCC can easily spread to distant sites.
What are the symptoms?
The earliest thing that usually happens in BCC is the presence of a small, shiny, skin-coloured lump which slowly enlarges. The centre of the lump may die, leaving an ulcer. Without treatment, the ulcer may reach 1–2 cm in diameter over 5–10 years. Slow but persistent growth causes local tissue destruction. Sometimes the tumour becomes fluid-filled or darker.
Some variants of BCC may reach a size of up to 10 cm.
The main symptom of squamous cell skin cancer is having a lump on the skin that grows and looks different from the skin around it. The lump is usually raised, crusted, and can be sore when touched. It might also bleed. Sometimes these types of cancer grow very quickly. They can show up anywhere on your skin reaching a diameter of up to 5 cm. But they usually show up on parts of the body that get the most sun, such as the face, lower legs, and forearms.
What treatments work?
The majority of skin cancers both melanocytic and non-melanocytic are treated by surgical removal. Other possible treatments include radiotherapy, as well as topical creams. Surgery is increasingly used first choice. Radiotherapy is now used rarely.
If you have had skin cancer, protecting your skin when you go outdoors can reduce your chance of getting it again. Using sunscreens and umbrellas may help.
What will happen to me?
Survival is largely dependent on how early the cancer was treated, and how complete the cancerous cells were removed. Most people are cured completely after surgery, but the cancer may come back and will have to be treated again. If the cancer spreads to other parts of the body, it is harder to cure.