• General Information About Skin Cancer
• Cellular Classification of Skin Cancer
• Stage Information for Skin Cancer
• Basal Cell Carcinoma of the Skin Treatment
• Squamous Cell Carcinoma of the Skin Treatment
• Treatment of Actinic Keratosis
• Changes to This Summary (07/29/2011)
• About This PDQ Summary
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General Information About Skin Cancer

There are three main types of skin cancer:

• Basal cell carcinoma (BCC).
• Squamous cell carcinoma (SCC).
• Melanoma.

BCC and SCC are the most common forms of skin cancer and are collectively referred to as nonmelanoma skin cancers. This summary only covers the treatment of nonmelanoma skin cancers. (Refer to the PDQ summary on Melanoma Treatment for more information.)

Incidence and Mortality

Nonmelanoma skin cancer is the most commonly occurring cancer in the United States. BCC is the more common type of the two nonmelanoma types, accounting for about three-quarters of nonmelanoma skin cancers.[1] The incidence of nonmelanoma skin cancer appears to be increasing in some,[2] but not all [3] areas of the United States. Overall U.S. incidence rates have likely been increasing for a number of years.[4] At least some of this increase may be attributable to increasing skin cancer awareness and resulting increasing investigation and biopsy of skin lesions.

Precise estimation of the total numbers and incidence rate of nonmelanoma skin cancer is not possible because reporting to cancer registries is not required. However, based on Medicare fee-for-service data, which were then extrapolated to the U.S. population, an estimated 2,152,500 persons were treated for nonmelanoma skin cancers in 2006.[4] That number would exceed all other cases of cancer estimated by the American Cancer Society for that year, which was about 1.4 million.[5] Although the two types of nonmelanoma skin cancer are the most common of all malignancies, they account for less than 0.1% of patient deaths caused by cancer.

Risk Factors

Epidemiologic evidence suggests that exposure to ultraviolet (UV) radiation and the sensitivity of an individual's skin to UV radiation are risk factors for skin cancer, though the type of exposure (i.e., high-intensity exposure and short-duration exposure vs. chronic exposure) and pattern of exposure (i.e., continuous pattern vs. intermittent pattern) may differ among the three main skin cancer types.[6,7,8] All three types of skin cancer are more likely to occur in individuals of light complexion who have had substantial exposure to sunlight, and skin cancers are more common in the southern latitudes of the Northern hemisphere. In addition, the immune system may play a role in pathogenesis of skin cancers.

Organ transplant recipients receiving immunosuppressive drugs are at an elevated risk of skin cancers, particularly SCC. Arsenic exposure also increases the risk of cutaneous SCC.[1] Serologic evidence from a population-based case-control study has shown a possible association between infection with the human papilloma virus (HPV) genus beta-species 1 and SCC.[9,10]

Related Summaries

Note: Other PDQ summaries containing information related to skin cancer include the following:

• Skin Cancer Prevention
• Skin Cancer Screening
• Unusual Cancers of Childhood (skin cancer in children)

References:

1. Thomas VD, Aasi SZ, Wilson LD, et al.: Cancer of the skin. In: DeVita VT Jr, Hellman S, Rosenberg SA, eds.: Cancer: Principles and Practice of Oncology. Vols. 1 & 2. 8th ed. Philadelphia, Pa: Lippincott Williams & Wilkins, 2008, pp 1863-87.
2. Athas WF, Hunt WC, Key CR: Changes in nonmelanoma skin cancer incidence between 1977-1978 and 1998-1999 in Northcentral New Mexico. Cancer Epidemiol Biomarkers Prev 12 (10): 1105-8, 2003.
3. Harris RB, Griffith K, Moon TE: Trends in the incidence of nonmelanoma skin cancers in southeastern Arizona, 1985-1996. J Am Acad Dermatol 45 (4): 528-36, 2001.
4. Rogers HW, Weinstock MA, Harris AR, et al.: Incidence estimate of nonmelanoma skin cancer in the United States, 2006. Arch Dermatol 146 (3): 283-7, 2010.
5. American Cancer Society.: Cancer Facts and Figures 2006. Atlanta, Ga: American Cancer Society, 2006. Also available online. Last accessed January 26, 2012.
6. Koh HK: Cutaneous melanoma. N Engl J Med 325 (3): 171-82, 1991.
7. Preston DS, Stern RS: Nonmelanoma cancers of the skin. N Engl J Med 327 (23): 1649-62, 1992.
8. English DR, Armstrong BK, Kricker A, et al.: Case-control study of sun exposure and squamous cell carcinoma of the skin. Int J Cancer 77 (3): 347-53, 1998.
9. Karagas MR, Nelson HH, Sehr P, et al.: Human papillomavirus infection and incidence of squamous cell and basal cell carcinomas of the skin. J Natl Cancer Inst 98 (6): 389-95, 2006.
10. Patel AS, Karagas MR, Perry AE, et al.: Exposure profiles and human papillomavirus infection in skin cancer: an analysis of 25 genus beta-types in a population-based study. J Invest Dermatol 128 (12): 2888-93, 2008.