Skin Cancer Overview
More than one million new cases of skin cancer are diagnosed each year in the United States, making it the most commonly diagnosed type of cancer among women and men.
The most common types of non-melanoma skin cancer are basal cell carcinoma and squamous cell carcinoma. Basal cell carcinoma can be disfiguring, but rarely metastasizes (spreads to distant sites in the body). Squamous cell carcinoma is more likely to metastasize than basal cell carcinoma, but metastasis is still uncommon.
An alarming trend in both melanoma and non-melanoma skin cancers is that the frequency of these cancers in young people appears to be on the rise.
The chance of an individual developing cancer depends on both genetic and non-genetic factors. A genetic factor is an inherited, unchangeable trait, whereas a non-genetic factor is a variable in a person’s environment, which can often be changed. Non-genetic factors may include diet, exercise, or exposure to other substances present in our surroundings.
The likelihood of skin cancer varies by skin, eye, and hair color. Fair-skinned individuals; those with blue, green, or grey eyes; and those with red or blonde hair have a higher risk. Skin cancer can also develop in people with darker skin or eye color, however, highlighting the importance of skin cancer prevention for everyone.
Individuals with a family history of skin cancer are also more likely to develop skin cancer. In rare cases this is due to a known familial cancer syndrome such as xeroderma pigmentosum, oculocutaneous albinism, or basal cell nevus syndrome.
Sun exposure: Exposure to ultraviolet radiation increases the risk of both non-melanoma skin cancer4 5 and melanoma. The ultraviolet radiation from the sun that reaches the earth includes both ultraviolet B (UVB) and ultraviolet A (UVA). Exposure to ultraviolet radiation from the sun is highest at latitudes closer to the equator, at high altitude, and when the sun in highest in the sky.
Tanning beds and sun lamps: Tanning beds and sun lamps also provide exposure to ultraviolet radiation, and are believed to increase the risk of skin cancer.
Immune suppression: People who are immunosuppressed, such as those undergoing organ transplantation, have an increased risk of developing skin cancer.4,5,6
Moles: Having a greater number of moles increases your risk of skin cancer.6 Atypical moles—also known as dysplastic nevi—carry a particularly high risk. Atypical moles look different than common moles; they may be larger or have an indistinct or irregular border or color.
Actinic keratoses: Actinic keratoses—also known as solar keratoses because of their link with sun exposure—are a type of precancerous change to the skin. They often appear as rough scaly patches on the skin or as a cracked and peeling area on the lower lip. Without treatment, some actinic keratoses will develop into squamous cell carcinoma.
Sun protection over the course of a lifetime is the most important aspect of skin cancer prevention. You can protect yourself from the sun with sun-protective clothing (such as hats, long-sleeved shirts, and long pants) with a tight weave, sunglasses, and a high-SPF sunscreen that protects against UVB and UVA. Staying in the shade may also be a good idea, especially when the sun is most intense.
When using sunscreen, apply a large amount and reapply frequently. It’s also important not to use sunscreen as an excuse for longer sun exposure. Individuals who use sunscreen to extend their time in the sun expose themselves to the same amount of UV radiation as if they had remained outside for a shorter period of time without sunscreen.
Keep in mind that UV radiation can be reflected off of snow, water, and sand. UV radiation is also more intense at high altitudes, at latitudes closer to the equator, and when the sun is higher in the sky. Because sun lamps and tanning booths also expose you to ultraviolet radiation, use of these tanning devices is best avoided.
For individuals with actinic keratoses, a precursor to squamous cell carcinoma, removal of the lesions may decrease the risk of developing squamous cell carcinoma. Because actinic keratoses are a sign that the skin has been damaged by sun exposure, individuals with actinic keratoses will also need to take special care to protect their skin from further sun damage.
For several types of cancer, progress in the area of cancer screening has led to earlier cancer detection and better outcomes. The term screening refers to the regular use of certain examinations or tests in persons who do not have any symptoms of a cancer but are at high risk for that cancer.
Though the U.S. Preventive Services Task Force has concluded that there is insufficient evidence to recommend routine skin cancer screening or skin self-exam, individuals and their physicians should be aware of changes to the skin that may signal cancer.
The most common signs of non-melanoma skin cancer involve changes to the skin, such as a new growth, changes in an old growth, or a sore that doesn’t heal.
For melanoma, using the “ABCDE” guidelines can help you recognize suspicious skin changes. “A” refers to asymmetry, “B” refers to border, “C” refers to color, “D” refers to diameter, and “E” refers to evolving. A skin lesion (typically a mole) may be a cause for concern if it is asymmetric (one half is different than the other half), has an irregular or jagged border, has more than one color, is larger in diameter than a pencil eraser, or is changing.
Self Exam: Performing skin self-examinations on a monthly basis may help you monitor changes to your skin. Use a mirror to examine your entire body for skin changes. It may be helpful to have someone with you to help examine hard-to-see areas such as your back. If you notice suspicious changes to your skin, you should promptly notify your physician.
Routine check-up: Depending on your age and personal and family history, a skin examination may be conducted as part of your regular health exams.
In order to learn more about melanoma or non-melanoma skin cancer, click on one of the following:
American Cancer Society. Cancer Facts and Figures 2009. Available at http://www.cancer.org/docroot/STT/stt_0.asp (Accessed May 26, 2010)
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
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
Rubin AI, Chen EH, Ratner D. Basal-Cell Carcinoma. New England Journal of Medicine. 2005;353:2262-2269.
Alam M, Ratner D. Cutaneous Squamous-Cell Carcinoma. New England Journal of Medicine. 2001;344:975-983.
Miller AJ, Mihm MC. Mechanisms of Disease: Melanoma. New England Journal of Medicine. 2006;355:51-56.
World Health Organization. Sunbeds, Tanning, and UV Exposure. Fact Sheet No. 287. Interim revision April 2010. Available at http://www.who.int/mediacentre/factsheets/fs287/en/print.html (Accessed May 26, 2010)
National Cancer Institute. What You Need to Know About™ Moles and Dysplastic Nevi. NIH Publication 99-3133. Updated 9/16/2002. Available at: http://www.cancer.gov/cancertopics/wyntk/moles-and-dysplastic-nevi (Accessed May 26, 2010).
U.S. Preventive Services Task Force. Screening for Skin Cancer. Release Date: February 2009. Available at: http://www.ahrq.gov/clinic/uspstf/uspsskca.htm (Accessed May 26, 2010).
Abbasi NR, Shaw HM, Rigel DS et al. Early diagnosis of cutaneous melanoma: revisiting the ABCD criteria. JAMA. 2004;292:2771-2776