What is the most important cause of NMSC?

The overwhelming majority of precancerous and cancerous skin lesions are caused by sun exposure. Several observations and epidemiologic studies support the role of ultraviolet light in the production of skin cancers:

1. Most NMSCs develop on skin chronically exposed to the sun, with 85% or more occurring on the head and neck.
2. The incidence of NMSC is lower in more polar latitudes (e.g., Minneapolis) than equatorial latitudes (e.g., Hawaii).
3. Epidemiologic studies clearly demonstrate that NMSCs are much more common in individuals with lighter skin than in individuals with darker skin.
4. NMSC can be induced in animal models by solar irradiation and prevented by the use of sunscreens.

Rigel D: Cutaneous ultraviolet exposure and its relationship to the development of skin cancer, J Am Acad Dermatol 58:S129–S132, 2008.

Taylor CR, Sober AJ: Sun exposure and skin disease, Annu Rev Med 47:181–191, 1996.