Skin problems health centre

Basal cell carcinoma

What is basal cell carcinoma?

Basal cell carcinoma is the most common form of skin cancer. These cancers almost never spread (metastasise) to other parts of the body. They can, however, cause damage by growing and invading surrounding tissue.

What are risk factors for developing basal cell carcinoma?

Light-coloured skin and sun exposure are both important factors in the development of basal cell carcinomas. About 20 percent of these skin cancers, however, occur in areas that are not sun-exposed, such as the chest, back, arms, legs, and scalp. The face, however, remains the most common location for basal cell lesions. Weakening of the immune system, whether by disease or medication, can also promote the risk of developing basal cell carcinoma.

According to the U.S. National Institutes of Health, ultraviolet (UV) radiation from the sun is the main cause of skin cancer. Artificial sources of UV radiation, such as sunbeds and tanning booths, can also cause skin cancer. The risk of developing skin cancer is also affected by where a person lives. People who live in areas with  high levels of UV radiation from the sun are more likely to develop skin cancer. In the United States, for example, skin cancer is more common in Texas than it is in Minnesota, where the sun is not as strong. Worldwide, the highest rates of skin cancer are found in South Africa and Australia, which are areas with  high levels of UV radiation. In addition, skin cancer is related to lifetime exposure to UV radiation. Most skin cancers appear after age 50, but the sun's damaging effects begin at an early age. Therefore, protection should start in childhood in order to prevent skin cancer later in life.

What does basal cell carcinoma look like?

A basal cell carcinoma usually begins as a small, dome-shaped bump and is often covered by small, superficial blood vessels called telangiectases. The texture of such a spot is often shiny and translucent, sometimes referred to as "pearly." It is often hard to tell a basal cell carcinoma from a benign growth like a flesh-coloured mole without performing a biopsy. Some basal cell carcinomas contain melanin pigment, making them look dark rather than shiny.

Basal cell carcinomas grow slowly, taking months or even years to become sizeable. Although spread to other parts of the body (metastasis) is very rare, a basal cell carcinoma can damage and disfigure the eye, ear, or nose if it grows nearby.

How is basal cell carcinoma diagnosed?

To make a proper diagnosis, doctors usually remove all or part of the growth by performing a biopsy. This usually involves taking a sample by injecting a local anaesthetic and scraping off a small piece of skin. This method is referred to as a shave biopsy. The skin that is removed is then examined under a microscope to check for cancer cells.