Skin cancer is the uncontrolled growth of cancer cells in the skin. Left untreated, these cells can spread to other organs and tissues, such as lymph nodes and bone. Skin cancer is the most common cancer in the United States.
The number of skin cancer cases due to tanning is higher than the number of lung cancer cases due to smoking.
Basal cell carcinoma is the most common form of skin cancer and squamous cell carcinoma is the second most common form. Actinic keratosis is the most common precancer.
Skin cancers, including melanoma, basal cell, carcinoma, and squamous cell carcinoma, often start as changes to your skin. They can be new growths or precancerous lesions, changes that are not cancer, but could become cancer, over a period of time.