Skin cancer is common. There are three main kinds:

• basal cell carcinoma, often known as a rodent ulcer;
• squamous cell carcinoma; and;
• malignant melanoma.

Fortunately, the commonest kind is the least dangerous, and the most dangerous kind, malignant melanoma, is the least common.

Skin cancer is very rare in children but is more common as people get older. At the age of 20 only about 1 person in 100,000 has non-melanoma skin cancer, whereas at the age of 80 about 200 per 100,000 have it.

In the case of malignant melanoma, at the age of 20, only one person per 300,000 (0.3 per 100,000) has the cancer, and at the age of 80 about 30 per 300,000 (10 per 100,000) have it.

The numbers of skin cancers rise with age because the main cause of all types of skin cancers is sunlight exposure. Sunlight contains ultraviolet light (UV), and this is what does the harm, particularly to the skin of babies and young children.

The numbers of skin cancers vary from country to country. In tropical countries with large white populations, the numbers are proportional to the amount of sunlight. Australia, South Africa and the Southern American states all have a very high incidence of skin cancer in their white populations. Black people are better protected by their skin colouring.

The cause of skin cancer is excessive exposure to sunlight.

Treatment

Rodent ulcer can be treated by direct surgical removal, by radiation or by freezing. The method advised is likely to depend on whether you are seen by a surgeon or by a dermatologist. All methods are equally effective.