Skin cancer is the abnormal growth of skin cells, most often developing on skin exposed to the sun. It occurs when damage to skin cells—commonly from ultraviolet (UV) radiation from sunlight or tanning beds—causes the cells to grow uncontrollably.
Skin cancer is the most common type of cancer in the United States. According to the American Cancer Society (ACS), millions of people are diagnosed with some form of skin cancer each year. The three main types are basal cell carcinoma, squamous cell carcinoma, and melanoma, with melanoma being the most serious but less common.
In many cases, skin cancer can be detected early because it appears on the surface of the skin. When found and treated early, most types of skin cancer are highly curable. However, some forms—particularly melanoma—can grow quickly and spread to other parts of the body if not treated promptly.
Researchers have found several factors that may increase a person’s risk of developing skin cancer, including:
Sun exposure: prolonged exposure to ultraviolet (UV) radiation from the sun or tanning beds is the primary cause of most skin cancers.
Fair skin: people with lighter skin, freckles, light hair, or light eyes have a higher risk because they have less melanin to protect against UV radiation.
Family history: individuals with a family history of skin cancer may have a higher risk of developing the disease.
Age: while skin cancer can occur at any age, the risk generally increases with age due to cumulative sun exposure over time.