Skin cancer is the most common of all cancers in the United States, accounting for as much as half of all cancer diagnoses, according to the American Cancer Society (ACS). It is also among the most curable, especially when caught in its early stages.

Skin cancer is divided into two main categories – melanoma and non-melanoma. Non-melanoma skin cancers are far more common, and less dangerous, than melanoma skin cancer. Melanoma skin cancers account for 4 percent of skin cancers overall, but cause 75 percent of skin cancer-related deaths each year, according to the Occupational Safety and Health Administration (OSHA).

The two most common forms of non-melanoma skin cancer are basal cell carcinoma, which begins in the skin’s lowest layer, and squamous cell carcinoma, which occurs in the higher layers of the skin. Squamous cell carcinoma rarely spreads (metastasizes) to other parts of the body. Basal cell carcinoma is unlikely to spread, but can invade other sites if left untreated.

Most cases of non-melanoma skin cancers are caused by overexposure to the sun’s ultraviolet (UV) rays. People with lightly pigmented skin, and those who have previously developed skin cancer, have the greatest risk of developing non-melanoma skin cancer. The ACS notes that more than 1 million cases of non-melanoma skin cancers are diagnosed every year and the incidence is rising. Many of these cases can be prevented by simply avoiding prolonged exposure to the sun, especially during peak hours and protecting skin with opaque clothing and sunscreen.

The most important warning sign of skin cancer is a new growth or spot on the skin that changes in size, shape, texture or color. A physical examination, followed by a skin biopsy taken from the suspected area will be used to diagnose whether cancer is present and, if present, its type and stage.

When skin cancer is detected early, it is highly treatable, usually with a simple excision (surgical removal). If not detected early, more aggressive surgery may be required.  In the early stages, non-melanoma skin cancer has an excellent prognosis.