Skin Cancer Myths

skin cancer

skin cancerTest your skin cancer awareness.

By Kari Bohlke, ScD

Several facts about skin cancer are probably familiar: it’s very common, it’s often linked with sun exposure, the most common types are basal cell carcinoma and squamous cell carcinoma, and the most deadly type is melanoma. Other facts are less well known, however, and may even seem counterintuitive. Prepare your skin for summer by learning the truth about several common skin cancer myths.

Myth 1: Skin cancer affects only light-skinned people.

Having light skin increases the risk of skin cancer, and skin cancer rates tend to be much higher among Whites than among non-Whites in the United States. Darker-skinned people are not immune to skin cancer, however, and may be at higher risk of death when skin cancer develops. A large US study found that although melanoma was relatively uncommon in non-Whites, non-Whites tended to have a more advanced stage of melanoma at the time of diagnosis.1 Compared with Whites, the probability of being diagnosed with Stage IV melanoma was more than twofold higher among Asians, more than threefold higher among Hispanics and American Indians, and more than fourfold higher among African Americans. The researchers concluded, “Melanoma is a public health concern for all ethnic populations.” To detect melanoma and other skin cancers at the earliest possible stage, it’s important for all of us to pay attention to changes in our skin and to discuss these changes with a doctor.

Myth 2: Skin cancer affects only the elderly.

As with many types of cancer, our risk of skin cancer increases as we age. Children and young adults can also be affected, however, and rates in young people appear to be on the rise. According to a US study of 15-to-39-year-olds, the rate of melanoma in young women increased from 5.5 cases per 100,000 people in 1973 to 13.9 cases per 100,000 people in 2004. Young men experienced a smaller increase, from 4.7 per 100,000 in 1973 to 7.7 per 100,000 in 2004.2 Melanoma is the second most common form of cancer among people between the ages of 15 and 29.3 These results highlight the importance of both skin cancer prevention and early skin cancer detection among young people.

Myth 3: Skin cancer appears only on sun-exposed parts of the body.

Although cancers such as basal cell carcinoma most commonly appear on sun-exposed areas of the skin, skin cancer can appear anywhere on the body. This includes the soles of the feet, the palms of the hands, and beneath fingernails and toenails.4

Myth 4: SPF tells me all I need to know about the sun protection of sunscreen.

Ultraviolet radiation is often divided into three types: UVA, UVB, and UVC. Although the sun emits all three types of ultraviolet radiation, only UVA and UVB reach the surface of the earth (UVC and some UVB are blocked by the ozone layer). UVB is the cause of most sunburns and has long been recognized as carcinogenic. UVA—which penetrates more deeply into the skin—was initially thought to be relatively safe, but it’s now recognized that both types of ultraviolet radiation are likely to contribute to skin cancer.5

The sun protection factor (SPF) of a sun block refers only to protection against UVB. There is currently no standard measure of protection against UVA. To get protection against both types of ultraviolet radiation, look for sun block that provides broad-spectrum protection against UVB and UVA. Apply sun block liberally (most people use far too little and get less protection than indicated on the bottle) and reapply at least every two hours.

It’s also important to keep in mind that sun block is only one part of a comprehensive sun protection program. Optimal sun protection also involves avoidance of the sun during peak hours and use of protective clothing such as hats.

Myth 5: Indoor tanning is safe.

Each year in the United States, an estimated 28 million people visit an indoor-tanning facility, with a majority of visits made by women and teenage girls.6 The bad news is that tanning beds—like the sun—expose the skin to ultraviolet radiation, and a growing body of research indicates that indoor tanners have an increased risk of skin cancer, including melanoma. Risk may be particularly high when indoor tanning begins at a young age.7

The International Agency for Research on Cancer classifies tanning beds and other UV-emitting tanning devices as Group 1 carcinogens, meaning there is sufficient evidence to conclude that these devices cause cancer in humans.5 Avoidance of tanning beds is recommended by the American Academy of Dermatology,8 the World Health Organization,9 and the US Environmental Protection Agency.10

Myth 6: The most common types of skin cancer aren’t dangerous.

Basal cell carcinoma and squamous cell carcinoma—the two most common types of skin cancer—are often highly curable. Nevertheless, the impact of these very common cancers should not be underestimated. Both types can cause extensive tissue destruction and disfigurement, and squamous cell carcinoma can metastasize (spread to other parts of the body) and be deadly.11

The take-home message? Give your skin the protection it deserves.

Each year more than 2 million people in the United States are treated for skin cancer.12 You can protect your skin by staying out of the sun during the middle of the day when the sun is most intense, wearing protective clothing such as broad-brimmed hats and long-sleeved shirts, and using a broad-spectrum sun block. If you notice a change to your skin, discuss it promptly with your physician. Skin cancer treatment is easiest and most effective when the cancer is caught early.

Getting Enough Vitamin D

Vitamin D contributes to bone health and may also reduce the risk of common chronic diseases such as cancer and heart disease. Vitamin D is formed in the skin in response to UVB radiation from the sun and can also be obtained from food and dietary supplements.

Studies suggest that many of us have low levels of vitamin D.15 Factors linked with low vitamin D levels include dark skin, older age, being overweight, and very low levels of sun exposure.16

Although sun exposure increases vitamin D levels, it also increases skin cancer risk and premature aging of the skin. Therefore the American Academy of Dermatology recommends nutritional sources and vitamin D supplements—not sun exposure—to achieve or maintain a healthy level of vitamin D.17 Your doctor can help you identify the sources and the amounts of vitamin D that are best for you.

Melanoma Treatment Remains an Important Research Focus

Melanoma is a difficult cancer to treat, and researchers continue to evaluate new approaches. One investigational drug that is showing promise—ipilimumab—targets a molecule known as CTLA4, which is found on the surface of T-cells and is thought to inhibit immune responses. By targeting this molecule, ipilimumab may enhance the immune system’s response against tumor cells. In a Phase III clinical trial among patients with previously treated Stage III or Stage IV melanoma, treatment with ipilimumab improved overall survival.13

Don’t Forget to Protect Your Eyes

Your skin is not the only part of you that’s vulnerable to sun damage. Your eyes also absorb ultraviolet radiation. Sun exposure contributes to eye problems such as cataracts, pterygium (a non-cancerous growth on the white of the eye), photokeratitis (a burn to the cornea), and skin cancer around the eyelids. To protect your eyes, experts recommend a combination of sunglasses that block 99 to 100 percent of both UVA and UVB rays; a wide-brimmed hat; and (for those who wear contact lenses) UV-blocking contacts. Protect your eyes even on cloudy days. Remember that snow, water, sand, and pavement reflect UV rays and can increase your exposure.14

References

1. Cormier JN, Xing Y, Ding M, et al. Ethnic differences among patients with cutaneous melanoma. Archives of Internal Medicine. 2006;166:1907-14.

2. Purdue MP, Freeman LE, Anderson WF, Tucker MA. Recent trends in incidence of cutaneous melanoma among US Caucasian young adults. Journal of Investigative Dermatology. 2008;128(12):2905-8.

3. Herzog C, Pappo A, Bondy M, Bleyer A, Kirkwood J. Malignant melanoma. In: Bleyer A, O’Leary M, Barr R, Ries LAG, eds. Cancer Epidemiology in Older Adolescents and Young Adults 15 to 29 Years of Age, Including SEER Incidence and Survival: 1975-2000. Bethesda, MD: National Cancer Institute. NIH Pub. No. 06-5767; 2006:53-64.

4. Gloster HM, Neal K. Skin cancer in skin of color. Journal of the American Academy of Dermatology. 2006;55:741-60.

5. El Ghissassi F, Baan R, Straif K, et al. A review of human carcinogens—part D: radiation. Lancet Oncology. 2009;10:751-52.

6. Levine JA, Sorace M, Spencer J, Siegel DM. The indoor UV tanning industry: a review of skin cancer risk, health benefit claims, and regulation. Journal of the American Academy of Dermatology. 2005;53:1038-44.

7. International Agency for Research on Cancer working group on artificial ultraviolet (UV) light and skin cancer. The association of use of sunbeds with cutaneous malignant melanoma and other skin cancers: a systematic review. International Journal of Cancer. 2007;120:1116-22.

8. El Ghissassi F, Baan R, Straif K et al. A review of human carcinogens—Part D: radiation. Lancet Oncology. 2009;10:751-752.

9. American Academy of Dermatology. Be Sun Smart.™ Available at: http://www.aad.org/public/sun/smart.html <http://www.aad.org/public/sun/smart.html> (Accessed October 25, 2010).

10.World Health Organization. Ultraviolet radiation and human health. Available at: http://www.who.int/mediacentre/factsheets/fs305/en/index.html <http://www.who.int/mediacentre/factsheets/fs305/en/index.html> (Accessed October 25, 2010).

11.U.S. Environmental Protection Agency. Action steps for sun safety. Available at: http://www.epa.gov/sunwise/actionsteps.html <http://www.epa.gov/sunwise/actionsteps.html> (Accessed October 25, 2010).

12. Alam M, Ratner D. Cutaneous Squamous-Cell Carcinoma. New England Journal of Medicine. 2001;344:975-983.

13.Rogers HW, Weinstock MA, Harris AR et al. Incidence estimate of nonmelanoma skin cancer in the United States, 2006. Archives of Dermatology. 2010;146:283-287.

14. Hodi FS, O’Day SJ, McDermott DF et al.Improved survival with ipilimumab in patients with metastatic melanoma. New England Journal of Medicine. 2010;363:711-23.

15. U.S. Environmental Protection Agency. Prevent eye damage. Protect yourself from UV radiation. Available at: http://www.epa.gov/sunwise/doc/eyedamage.pdf Accessed October 20, 2010.

16. Zadshir A, Tareen N, Pan D, Norris K, Martins D. The prevalence of hypovitaminosis D among US adults: Data from the NHANES III. Ethnicity and Disease. 2005;15(4 Suppl 5):97-101.

17. Tang JW, Wu A, Linos E et al. High prevalence of vitamin D deficiency in patients with basal cell nevus syndrome. Archives of Dermatology. 2010;146:1105-10.

18. American Academy of Dermatology. American Academy of Dermatology Issues Updated Position Statement on Vitamin D. No Safe Threshold for Sun or Indoor Tanning Exposure. Available at: http://www.aad.org/media/background/news/Releases/American_Academy_of_Dermatology_Issues_Updated_Pos/ Accessed October 20, 2010.

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