Skin Cancer: Protect Yourself - Know the Facts

July 29, 2009

By Lindsay Grace Weber

The Center for Disease Control identifies skin cancer as both the most common, and the most preventable, type of cancer in the U.S. [1] Though most skin cancer prevention and awareness campaigns target individuals in higher risk groups—i.e. light skinned individuals who burn or freckle easily—people with darker skin are also at risk for developing skin cancer. Individuals with increased skin pigmentation, including African-American, Asian, Latino and Indigenous people, do have additional protection from the harmful UV rays of the sun that lead to skin cancer. Despite this added protection, skin cancer is associated with higher mortality and morbidity within these populations due to the atypical presentation of skin cancer in dark skin, and the subsequent misdiagnosis of skin cancer by medical professionals. [2] With the summer sun now out in full force, it is important that all individuals take precautions against skin cancer.

What is Skin Cancer?
There are three types of skin cancer—basal cell carcinomas (BCC), squamous cell carcinomas (SCC), and melanoma. BCC, the most common form of skin cancer, is highly curable if found early, though it is associated with a high mortality rate if left untreated. SCC is the second most common type, and is also highly curable if diagnosed at an early stage. SCC is more common than BCC in dark skin, comprising 66% of skin cancer cases in people of color, often developing from pre-existing scar tissue, burns, and chronic inflammatory skin conditions (such as sores, ulcerations). [3] SCC is often found on mucous membranes and lips, and if left untreated will spread to other areas of the body, making it much harder to treat.

The third and most dangerous type of skin cancer is melanoma. Though it is the least common form, melanoma is more dangerous than BCC and SCC due to its ability to spread quickly to other areas of the body. [4] Most cases of melanoma are caused by exposure to UV rays and sunlight, and presents either in situ (as a localized tumor on the outer layer of skin) or invasive (where the cancer cells have permeated the outer layer of skin and begun spreading to other areas of the body). Of the four categories of melanomas—acral lentiginous, superficial spreading, lentigo maligna, and nodular melanoma—the first three begin in situ and progress to an invasive stage, while nodular melanoma is invasive from the start.

Melanoma is the most deadly form of skin cancer in people of color, as it is often diagnosed in darker skin after it has progressed to an invasive stage. On darker skin it often presents in areas with little to no sun-exposure; thus, melanomas are often misdiagnosed as plantar warts (foots warts), tinea nigra palmaris (fungus of the palm), or talan noir (dark nail). [5] Many general healthcare providers have little experience recognizing melanomas on darker skin, which makes it important to educate yourself and your loved ones about skin cancer, and to seek the expertise of a dermatologist who is familiar with all forms of skin cancer.

Who is at Risk?
Skin cancer is most commonly diagnosed in individuals with lighter skin tone (less pigmentation), with a personal or family history of skin cancer, or with a history of one or more severe blistering sunburns before the age of 18. [6] BCC is most common in elderly individuals, while SCC is frequently linked to family history of the disease. [7] Individuals with discoid lupus or human papillomavirus (HPV) are also at a higher risk for developing BCC and SCC. [8] Higher risk for developing SCC includes pre-existing skin conditions, such as actinic keratosis, sctinic cheilitis, leukoplakia, and Bowen’s disease, as well as exposure to prolonged x-rays. [9]

According to the 2005 Center for Disease Control cancer rates, the skin cancer incidence rate (for all three types) amongst Indigenous peoples in the U.S. was 4.8 per 100,000 people, and the rate for melanoma was 4.1, with a 1.3 mortality rate. While these rates are relatively low compared to populations with lighter skin, the significant melanoma mortality rate in Indigenous communities points to late or misdiagnosis, impressing further the need to be vigilant and aware about the risks associated with skin cancer. [10] Though Indigenous people’s skin may not be as vulnerable to harmful UV rays and sunburn, and skin cancer is relatively rare in Indigenous communities, no one immune to developing skin cancer. Young children and Indigenous people with lighter skin are particularly at risk for skin cancers caused by prolonged sun exposure.

Other Risk Factors
In addition to sun exposure, family history, and disease-associated predisposition to skin cancers, there are other risk factors that disproportionately affect Indigenous communities, most notably environmental factors. BCC can form on non-sun exposed areas of the body as a result of contact with arsenic and exposure to radiation. Indigenous people in the Southwest U.S. are thus more at risk for BCC due to naturally occurring arsenic deposits in local water sources. [11] Additionally, Indigenous communities ‘downwind’ of major nuclear testing or storage sites in the Western U.S.—including parts of California, Nevada, Utah, New Mexico, Washington, and Idaho—are also at a higher risk for developing skin cancer due to prolonged exposure to radiation. Individuals who work jobs associated with radioactive materials, including uranium mining and mill work, are also at higher risk for developing BCC due to exposure. [12] Exposure to insecticides, herbicides, fungicides and seed treatments, arsenic and ethylene glycol has been shown to increase the risk of developing SCC as well. People working with or around these chemicals, most notably farm and automobile workers, should be cautious of abnormal areas on the skin and seek regular skin exams. [13]

Symptoms
The American Cancer Society recommends monthly self administered skin exams, in addition to regular screenings by a health professional—once a year for people over the age of 40, and every three years for people ages 20-40. [14] Information about free skin cancer screenings and instructions for self-examination can be found at the end of the article.

Symptoms of BCC and SCC are similar, and may be confused with psoriasis and eczema in people with dark skin. They include the following symptoms:

• One or more open sores that bleed, ooze, form crusts, or remain open for 3+ weeks
• Red or irritated patch on the skin; patches are persistent, scaly, and may crust over, bleed, itch and hurt
• Wart-like growths that crust and bleed
• Shiny, translucent bumps; often appear tan, black, or brown on darker skin.
• Small pink growth with a crusted indentation in the center; often enlarges slowly, developing small blood vessels on the surface
• Appearance of scar-like areas on the skin, white or yellow in color, with a waxy texture and vaguely defined borders [15]

Symptoms of melanoma in dark skin often present on the bottoms of feet, palms and nails. Follow the ABCD guidelines for identifying melanomas:

• ASYMMETRY: One half of the abnormal area is different from the other half
• BORDERS: The growth has irregular edges
• COLOR: Color of the growth changes from one point to another; different shades of tan, brown, or black, and occasionally white, red or blue
• DIAMETER: The growth is usually (but not always) larger than 6 mm in diameter, or approximately the size of a pencil eraser
  

Acral lentiginous melanoma (ALM) is the most common type of melanoma in dark skin. Symptoms of ALM may present differently than other melanomas. ALM is often found in non-exposed areas, such as inside the mouth, nose, anus, urinary tract, and female genitals, making it more difficult to identify in its early stages. Other signs of ALM include:

• Bruises or sores that do not heal, or the continual re-appearance of a bruise or sore in the same area
• Stripe beneath a nail, which can expand beyond the nail onto the surrounding skin
• New or changing scar, especially if scar is the result of previous burn or traumatic injury
• Scaly patch with thickened skin and well-defined border, darker than surrounding skin. The area may resemble a wart, take the shape of a horn, and have a velvety texture
• White patch on tongue or inside mouth
• Blotchy skin, particularly on the legs. Areas of skin exposed continually to the heat of a fire or stove at a young age can lead to skin cancer later in life [16]
  

Melanomas spread quickly, and both BCC and SCC have the potential to spread to other parts of the body if left untreated. If you observe any of the above symptoms, make an appointment with IHS or an IHS contracted dermatologist immediately.

Preventative Measures
Protect yourself in the sun! Wear and continually reapply sunscreen (SPF 15+), cover up with a light shirt, hat and sunglasses (with UV protection), and seek shade when the sun is at its highest point. Following the shadow rule when out in the sun will also provided added protection against skin cancers; if your shadow is shorter than you are, sun exposure is at its strongest (and most harmful) and should be avoided. [17]

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More Information about Skin Cancer and Prevention
http://brownskin.net/cancer.html
http://www.skincarephysicians.com/SkinCancerNet/skin_of_color.html
http://www.nlm.nih.gov/medlineplus/skincancer.html
http://www.healthywomen.org/condition/skin-cancer

Information about Self-Examination
http://brownskin.net/skHealth.html
http://www.skincarephysicians.com/SkinCancerNet/skin_examinations.html
http://www.skincarephysicians.com/SkinCancerNet/hidden_melanomas.html
Mole Chart: http://www.melanomamonday.org/documents/08_402%20Melanoma%20Monday%20Mole%20tear-Off.pdf

Free Screenings
Contact your local IHS facility to see if they offer skin cancer screenings. If not, the following links identify free skin cancer screening sites throughout the U.S.
http://skincancertakesfriends.org/sctf08/index.jsp
http://www.aad.org/public/exams/screenings
http://www.skincancer.org/road-to-healthy-skin-tour-2009.html

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Sources:
[1] U.S. Department of Health and Human Services. Centers for Disease Control and
Prevention. (January 7, 2009). Basic Information about Skin Cancer. Retrieved from http://www.cdc.gov/cancer/skin/basic%5Finfo/
[2] Brown, Susan Taylor. (2008). Ethnic Skin Care: Skin Cancer. Retrieved from http://brownskin.net/cancer.html
[3] Brown. (2008). Ethnic Skin Care: Skin Cancer.
[4] U.S. Department of Health and Human Services. (2009). Basic Information about Skin Cancer.
[5] Brown. (2008). Ethnic Skin Care: Skin Cancer.
[6] Huntsman Cancer Institute. (February 2004). Risk Reduction for Native Americans. Retrieved from http://www.huntsmancancer.org/pdf/nao/Risk.pdf
[7] Brown. (2008). Ethnic Skin Care: Skin Cancer.
[8] Byrd-Miles, Katina., Ella L. Toombs, Gary L. Peck. Skin cancer in individuals of African, Asian, Latin-American, and American Indian descent: differences in incidence, clinical presentation, and survival compared to Caucasians. (January 2007). Journal of Drugs and Dermatology 6(1): 10-17.
[9] Brown. (2008). Ethnic Skin Care: Skin Cancer.
[10] United States Cancer Statistics Working Group. United States Cancer Statistics: 1999-2005. Incidence and Mortality Web-based Report. Atlanta: U.S. Department of Health and Human Services, Center for Disease Control and Prevention and National Cancer Institute; 2009. Retrieved from http://www.cdc.gov/uscs
[11] Barrett, Julia R. Health on the Banks of the Rio Grande. (May 2005). Environmental Health Perspectives 113(5): 304-308.
[12] George, Patricia., Abel Russ. Nuclear Testing and Native Peoples. (2008). Urban Habitat. Retrieved from http://www.urbanhabitat.org/node/165; and Kamps, Kevin. Environmental Racism, Tribal Sovereignty and Nuclear Waste. (February 15, 2001). Nuclear Information Resource Service. Retrieved from http://www.nirs.org/factsheets/pfsejfactsheet.htm
[13] Mitropoulos, Panagiotis., Robert Norman. Occupational nonsolar risk factors of squamous cell carcinoma of the skin: A population-based case-controlled study. (2005). Dermatology Online Journal 11 (2): 5.
[14] Cancer Facts and Figures. (2008). American Cancer Society. MedlinePlus. Retrieved from http://www.nlm.nih.gov/medlineplus/ency/article/000850.htm
[15] Brown. (2008). Ethnic Skin Care: Skin Cancer.
[16] American Academy of Dermatology. Skin Cancer: A Fact of Life in Skin of Color. (2009). Retrieved from http://www.skincarephysicians.com/SkinCancerNet/skin_of_color.html
[17] U.S. Department of Health and Human Services. (2009). Basic Information about Skin Cancer.