What is skin cancer?
Skin cancer is the most common type of cancer, with over 100,000 new cases diagnosed in the UK each year. The disease is caused by damage to cells, usually by too much exposure to ultraviolet (UV) rays from the sun. The damage to the cells causes them to grow out of control and this leads to the formation of an abnormal mass of tissues called a tumour. Skin cancers usually develop in the outer layer of the skin, so the tumours are often detected at an early stage and can be treated successfully.
Types of skin cancer
The three most common forms of skin cancer are basal cell carcinoma, squamous cell carcinoma (together known as non-melanoma cancers) and melanoma.
Non-melanoma cancers are growths on the skin surface limited to a specific area that do not normally spread to other parts of the body.
Basal Cell Carcinoma
Basal cell carcinoma (BCC) is the most common human cancer and is the most common form of skin cancer, accounting for 80-90% of non-melanoma skin cancers.
BCCs are abnormal, uncontrolled growths or lesions that arise in the skin’s basal cells, which line the deepest layer of the epidermis (the outermost layer of the skin). BCCs often look like open sores, red patches, pink growths, shiny bumps, or scars.
Exposure to UV radiation (particularly in childhood and adolescence) is the major cause of BCC and tumours normally develop on sun-exposed areas of the skin, especially the face and neck. BCC occurs most often in white populations and is uncommon in darker skinned races. The closer Caucasians live to the equator, the greater the risk of developing BCC.
Other risk factors include having a fair complexion (red or blond hair, light eye colour), exposure to radiation, genetic predisposition (e.g. Gorlin’s syndrome) and a diet high in fat and low in vitamins.
Because exposure to the sun can cause BCC, people whose work requires long hours outside or people who spend their leisure time in the sun are particularly susceptible to developing BCC.
People who have had one BCC are more at risk of developing another one, either in the same place or somewhere else on the body, especially if they are male, more than 60 years old, had BCC on their torso or had a type of BCC called superficial.
In the past, more men had BCC than women but the number of women being diagnosed with BCC is rising.
Squamous Cell Carcinoma
Squamous cell carcinomas are much less common and also normally appear on sun-exposed areas of skin. These tumours are generally more severe than basal cell carcinomas and are more likely to spread to other areas of the body, although this is still uncommon.
Both types of non-melanoma cancers are usually treated by surgical removal of the tumour, however radiotherapy is also used in some cases.
Melanoma is the most severe form of skin cancer and causes the majority of deaths related to the disease. However, there is a good chance of cure if it is diagnosed at an early stage.
Melanomas are tumours that develop from melanocytes, the cells in the skin that produce a pigment called melanin. The role of melanin is to protect the skin from the UV rays of the sun. Melanomas normally develop from moles.
Moles are small areas of skin that are darker in colour than the surrounding skin. They are made up of a cluster of melanocytes. Moles are usually circular or oval with a smooth edge. The number of moles normally increases with age and people with fair skin often have more moles than people with darker skin.
The location of melanomas on the body can vary greatly and includes the head, neck, torso (chest, stomach and back) and legs. The most common area for men to develop tumours is on the torso, especially the back. For women, the area most at risk is the legs.
Although melanoma is the least common of the three forms of skin cancer, the number of cases is growing at a fast rate, higher than any other type of cancer. Melanoma is now the sixth most common cancer for men and women in the UK. The disease is particularly common in white people living in sunny climates and is more common in women than men. In adults the chance of developing the disease generally increases with age. Melanoma is rare in children. However, melanoma is the most common cancer in 15–34 year olds.
RXUKERIV00031a September 2013