Skin Cancer: What you need to know
The cause of the majority of skin cancers is over exposure to the sun. About nine out of ten non-melanomas and six out of ten cases of malignant melanoma are attributed to sun exposure from an early age.
It's widely agreed within medical circles that most skin damage from the sun happens before the age of 20 - in fact the majority of us receive 80% of our lifetime exposure to the sun by that age.
The main cause of skin cancer is damage from ultraviolet (UV) radiation given off by the sun. It penetrates the skin and causes damage to the cells inside.
The sun contains light rays known as ultraviolet A and ultraviolet B rays. UVA radiation goes deeply into the skin and weakens the cells against cancer. UVB causes sunburn and plays an important part in the long-term development of the most common basal cell and squamous cell carcinomas by causing damage to these cells within the skin.
Skin cancer develops very slowly. Sunburn which causes severe skin damage in your teens could develop into cancer more than 20 years later.
Ultra Violet Radiation and Skin Cancer
UV radiation also causes malignant melanomas but in the majority of cases long-term exposure to the sun is not the main problem. Intermittent exposure and repeated sunburn are far more damaging.
A study in Australia showed that people who worked indoors year round and then spent two holiday weeks exposing their bodies to intense sunlight had a higher risk of malignant melanoma than people who regularly spent time in the sun.
But there are other causes of skin cancer. It's a well known fact that global warming has caused a reduction of ozone in the atmosphere. Ozone filters out and reduces the amount of UV light which reaches the earth - so with less ozone, more harmful rays are reaching us.
Certainly the levels of skin cancer are on the rise and the World Health Organization (WHO) estimates that the continuing reduction of the ozone layer will cause a further 300,000 non melanomas and 4,500 malignant melanomas over the next few years.
Radiotherapy is also a possible cause. People with other forms of cancer, such as breast cancer, may receive radiotherapy treatment on the affected area. This type of treatment can make the skin very sensitive and in some cases burn it, making it susceptible to sun damage.
The use of sun beds and their possible link to skin cancer has certainly hit the headlines over the past few years. The problem is that they have not been around long enough to prove conclusively that they cause as much malignant melanoma as sunlight. However, what researchers do know is that the UVA light used in sun beds can be responsible for all types of cancer.
The exact cause of skin cancers which develop on unexposed areas, such as the soles of the feet, is unknown. Researchers are currently looking at whether skin cancer can also be hereditary or if there is a genetic predisposition to the disease.