February 6, 2009

What is Nonmelanoma Skin Cancer?

Skin cancer is often divided into two broad categories: melanoma and nonmelanoma. Non-melanoma skin cancer refers to several different types of skin cancer, but the most common types are basal cell carcinoma and squamous cell carcinoma.

Basal cell carcinoma accounts for roughly 80 percent of all cases of nonmelanoma skin cancer.1 Basal cell carcinoma most commonly develops on sun-exposed skin, with the head (particularly the nose) and neck being the most common sites. This type of skin cancer very rarely metastasizes (spreads beyond the skin), but it can cause extensive local damage to the skin and surrounding tissues.

Squamous cell carcinoma accounts for roughly 20 percent of all cases of nonmelanoma skin cancer.2 Squamous cell carcinoma is more likely than basal cell carcinoma to spread to lymph nodes or distant parts of the body, though this happens infrequently. Squamous cell carcinoma may be preceded by a precancerous condition known as actinic keratoses (also known as solar keratoses). Actinic keratoses often appear as rough scaly patches on the skin. An alarming trend in both melanoma and nonmelanoma skin cancers is that the frequency of these cancers is increasing—including the frequency in children and young adults.3 4 This increasing frequency is likely due to changing patterns of sun exposure. Sun exposure is an important risk factor for both melanoma5 and nonmelanoma skin cancer.2 3


1 Rubin AI, Chen EH, Ratner D. Basal-Cell Carcinoma.New England Journal of Medicine. 2005;353:2262-2269.2 Alam M, Ratner D. Cutaneous Squamous-Cell Carcinoma. New England Journal of Medicine. 2001;344:975-983.

3 Christenson LJ, Borrowman TA, Vachon CM et al. Incidence of Basal Cell and Squamous Cell Carcinomas in a Population Younger Than 40 Years. JAMA. 2005;294:681-690.

4 Strouse J, Fears T, Tucker M, Wayne A. Pediatric Melanoma: Risk Factor and Survival Analysis of the Surveillance, Epidemiology and End Results Database. Journal of Clinical Oncology. 2005; 23: 4735-4741.

5 Miller AJ, Mihm MC. Mechanisms of Disease: Melanoma. New England Journal of Medicine. 2006;355:51-56.

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Tags: Skin Cancer, Uncategorized