Skin cancer facts

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Up to two-thirds of all cancers may be prevented through dietary and lifestyle changes. In the case of skin cancer, this could not be more true.

To increase awareness of skin cancer risks and prevention strategies, renowned experts on the front lines of skin cancer research, treatment and patient care at The University of Texas M. D. Anderson Cancer Center answer important questions about skin cancer risk factors, sunscreen and skin protection and skin cancer screening and treatment.

Skin Cancer Risk Factors

Q: Can you be genetically pre-disposed to skin cancer?
A: With skin cancer, the environment plays a role, but individuals can be born with a genetic disposition toward, or vulnerability to, developing cancer. While anyone can develop skin cancer, the risk is greatest for people with light-colored skin that freckles easily. About 10 percent of all patients with melanoma have family members who also have had the disease. Further, research has identified certain mutations in genes and chromosomes that play a role in the formation of melanoma.

Q: How will I know if I have skin cancer? What are the differences between normal and abnormal moles?
A: Symptoms of nonmelanoma and melanoma skin cancers vary from person to person, therefore it is important for individuals to recognize any changes in the skin that are unusual. Become familiar with the pattern of your moles, blemishes and freckles so that changes over time may be identified.

Possible signs and symptoms may include A:

  • New spot
  • Mole that changes size shape or color
  • Sore that doesn't heal
  • Spot that is itchy, tender or painful

For melanoma, the first sign often is a change in the size, shape, color or feel of an existing normal mole. Melanomas can vary greatly in the way they look, but generally show one or more of the "ABCDE" features:

  • Their shape may be Asymmetrical.
  • Their Borders may be ragged or otherwise irregular.
  • Their Color may be uneven, with shades of black and brown.
  • Their Diameter may change in size.
  • Their Elevation may become raised or grow in height.

Q: Are there risk factors beside sun exposure?
A: While the sun's ultraviolet rays are a major cause of skin cancer, there are other lifestyle, environmental and genetic factors that may increase one's risk of developing the disease. M. D. Anderson experts recommend regular self-screenings and taking extra precaution for individuals with:

  • Light-colored skin - the fairer the skin, the higher the risk of skin cancer.
  • Large numbers of normal or atypical moles (more than 50).
  • A family history of skin cancer.
  • Occupational exposure to coal, tar, pitch, creosote, arsenic or radium.
  • More than three blistering sunburns before age 18.

Q: What is the difference between UVA and UVB rays?
A: Sunlight consists of two types of harmful rays - ultraviolet A rays and ultraviolet B rays. The UVB rays are the sun's burning rays (which are generally blocked by window glass) and are the primary cause of sunburns. UVA rays (which pass through window glass) penetrate deeper into the dermis, or base layer of the skin. UVA rays also contribute to sunburns and signs of aging. Both UVA and UVB rays can cause suppression of the immune system.

Q: Does where I live affect my exposure to UV rays?
A: People who live in areas with higher levels of UV radiation from the sun, such as regions closer to the Earth's equator, have higher risk of skin cancer. In the southern United States, the sun's UV rays are strongest between 10 a.m. and 4 p.m., which are the times to avoid sun exposure.

Q: Are there areas of my body more susceptible to skin cancer than others?
A: Skin cancers, which develop in the epidermal layer, are classified as nonmelanoma (cancers occurring in the basal or squamous cells) and melanoma (cancers occurring in the melanocytes, or pigment cells). Basal cell and squamous cell carcinomas are the most common on areas of the body regularly exposed to sunlight, such as the face, ears, neck, lips or back of the hands.

Melanoma, which is rare and more life threatening, tend to be found on areas that are intermittently exposed to sunlight. In men, melanomas are commonly found on the chest or back. In women, these areas often include the back, thighs and calves. Melanoma skin cancers can develop on or around an existing mole.

Q: Do darker-skinned people such as African-Americans and Hispanics experience the same risk of skin cancer as Caucasians? Do skin cancer treatments differ for dark-skinned people?
A: While the incidence of skin cancer, including melanoma, is relatively low in ethnic populations with darker skin, the risks are equal. Melanoma often appears in ethnic populations on non-sun-exposed sites with less pigment, such as the palms, soles and the areas around the nails. One recent study found that melanoma rates among Latino males are growing at rates double that of Caucasian males. The study also found that many doctors are not aggressive enough in checking for melanomas in ethnic patients or in following up on them when they are detected - leading to more developed, "thicker" tumors that are more difficult to treat.

Tanning and Sunburns

Q: Is tanning in a tanning bed safer than tanning in the sun?
A: There is no such thing as a safe tan. Tanning beds produce the same UVA radiation as the sun and are not a safe alternative. Any tan is a sign of skin damage - avoid going to tanning salons or using any other artificial light sources.

Q: If I don't burn, am I still causing skin damage?
A: Even if you don't burn, any change in skin color is a sign of permanent skin damage that may lead to melanoma and other skin cancers, as well as premature aging, including wrinkles and age spots.

Q: Are there any trends in changing attitudes among teens and young adults about suntans?
A: Despite recent efforts to reach teens with skin cancer prevention information, their perception of tanning has not changed. In a survey by the American Academy of Dermatology, 79 percent of teens aged 12 to 17 were aware that getting a suntan was dangerous for their skin; another 81 percent were aware that childhood sunburns increase their risk of developing skin cancer. However, 60 percent admitted they suffered at least one sunburn during the summer of 2004 and 66 percent believed that people appear physically more healthy with a tan.

Skin Protection - Sunscreen

Q: How long does it take for sunscreen to begin working (i.e. do I need to apply it before sun exposure)?
A: Sunscreen should be applied 30 minutes before going into the sun so it has a chance to be absorbed by the skin. Moisture from humidity or sweat doesn't allow the sunscreen to adhere to the skin as effectively.

Q: How often do I need to reapply sunscreen?
A: Sunscreen should be reapplied about every 60 to 90 minutes, or after swimming or heavy perspiration, even if the sunscreen is waterproof or sweat-proof.

Q: Is it true SPF levels higher than 30 are not necessary?
A: A sunscreen with a SPF of 15-30 is a good choice for most people. The Food and Drug Administration no longer approves labeling sunscreens with a SPF over 30, citing research has not shown SPFs over 30 to significantly increase protection.

Q: Is make-up with SPF sufficient? Or do I need to use sunscreen also?
A: This can depend on skin type. For light-skinned individuals, cosmetic make-up containing SPF is not adequate. The most effective strategy for skin protection is to apply sunscreen with SPF 15 or higher (as one would a moisturizer). Check to see the sunscreen contains the ingredients octylcrylene, benzophenone or avobenzone, these offer the best protection against harmful UV rays. Any additional sunscreen in make-up is a plus, but should not be relied on solely.

Q: If I use both regular sunscreen and make-up with SPF, which should I apply first?
A: Sunscreen should be applied after a shower or bath and before applying makeup. Sunscreen should be allowed to be fully absorbed by the skin before applying make-up with SPF; chemicals in the two products may mix and actually lower the overall SPF effectiveness.

Q: If sunscreen is waterproof, how often does it need to be reapplied?
A: It is best to choose a sunscreen that is water-resistant so that sweating or swimming cannot easily remove it. These sunscreens stay on the skin longer even if they get wet, but they are not actually "waterproof" since no product is completely waterproof. Rather, they should be labeled as "water-resistant" or "very water-resistant." Like other types of sunscreens, water-resistant sunscreens still need to be reapplied often (about every 60 to 90 minutes) when sweating or swimming, and especially after towel drying, when it can be rubbed off.

Beyond Sunscreen: Other Methods of Skin Cancer Prevention

Q: Are there other things I can do besides wearing sunscreen to protect myself from skin cancer?
A: To provide added protection, use clothes to cover up, such as long sleeved shirts and pants (dark clothing with a tight weave is best), a broad-brimmed hat and sunglasses. Since most clothing offers minimal protection, wear sunscreen under clothing and be sure sunglasses have UVA and UVB protections - which should filter at least 80 percent of the sun's rays. Also find shade wherever possible, or use an umbrella to shield yourself.

Q: What type of clothing offers the best protection from UV rays?
A: Covering up is a valuable skin cancer prevention strategy and what a person wears makes all the difference. Research shows a white cotton T-shirt only provides the same protection as applying a sunscreen with SPF 5. If the shirt is wet, it loses about a third of its sun-blocking properties. For better protection, experts recommend choosing fabrics that are100 percent polyester; dark colored; tightly woven and loose fitting, and to cover up with dry clothing after swimming. Sun-blocking clothes with sun protection woven into the fabric are another option. This lightweight gear, available through catalogs and sporting good stores comes in Ultraviolet Protection Factor (UPF) 15 to 50 and has been shown to block 95 percent of UVB rays, both wet and dry.

Q: Can vitamins and supplements help protect against skin cancer?
A: Although no dietary supplement has been shown to completely prevent cancer, research being conducted in the field is showing that some nutrients, vitamins and phytochemicals may have the potential for providing additional protection against some cancers.

Researchers at M. D. Anderson recently found that a naturally occurring compound in cranberries, grapes and peanuts - known as resveratrol - is linked to anti-cancer activity and may help prevent a wide variety of cancers including skin cancer. In laboratory studies, curcumin, the pungent yellow spice found in turmeric and curry powder, blocks a key biological pathway needed for development of melanoma and other cancers, say M. D. Anderson researchers. A review of previous studies by the American Cancer Society found that drinking green tea may help prevent skin cancer - and it may even be effective when added to skin care creams. Vitamin A may also have a direct anti-cancer effect. Human studies are currently looking at whether naturally occurring and synthetic vitamin A derivatives (retinoids) can inhibit tumor development in certain rare forms of leukemia, as well as cancers of the airway, upper bowel, skin and cervix.

Q: Will washing clothes with an SPF detergent add a significant level of protection against UV rays?
A: There are products that increase the UV protection in clothing, such as cotton t-shirts, with a single wash. Such additives, containing a new UV protectant know as TINOSORB(r) FD and can be added to a regular wash cycle to block up to 96 percent of the sun's harmful rays for up to 20 washes. While such products can offer additional peace of mind, it is important to remember to apply sunscreen to exposed skin and wear a hat and sunglasses.

Skin Cancer Prevention and Children

Q: I never wore sunscreen as a child, but I always wear it now. Should I still be worried about skin cancer?
A: Skin cancer is uncommon in children. However, damage that later results in skin cancer is accumulated in childhood. History of exposure to UV light (whether intermittent or year round, even if the exposure was years ago) holds the answer to how great the risk factor. While melanoma in people under age 20 is uncommon, it is not unheard of and can occur at any age.

Q: How can I protect my baby/children from sun exposure?
A: Babies should never be exposed to direct sunlight and sunscreen should not be applied to infants under six months of age. Instead, shield them with protective clothing when out during the day.

Children should follow sun safety guidelines - use sunscreen of at least SPF 15 and apply it often, wear sun protective clothing and limit time in the sun, especially between 10 a.m. and 4 p.m. when UV light is strongest. Research shows that regular use of sunscreen during the first 18 years of life could reduce the lifetime incidence of skin cancer by 78 percent.

Additionally, experts in epidemiology encourage parents to model good behavior for the children when it comes to sun safety. If sunscreen, hats and other forms of sun protection are a family routine, children are more likely to continue this behavior, as they grow older.

Skin Cancer Screening

Q: Should I begin being screened for skin cancer at any particular age?
A: The risk of skin cancer increases with age; therefore, it is never too early to begin annual skin examinations. While no specific age is recommended to begin screening for skin cancer (annual head-to-toe skin examinations are recommended for adults), it is important to know your skin type and possible risk factors.

Skin Cancer Treatment

Q: How is skin cancer diagnosed and treated?
A: Skin cancer is typically diagnosed by a skin examination. A doctor or nurse checks the skin for bumps or spots that look abnormal in color, size, shape, or texture. A biopsy is performed where all or some part of the abnormal-looking growth is cut from the skin and viewed under a microscope by a pathologist to see if cancer cells are present. There are 3 main types of skin biopsies:

  • Shave biopsy: a sterile razor blade is used to "shave-off" the abnormal-looking growth.
  • Punch biopsy: a special instrument called a punch or a trephine is used to remove a circle of tissue from the abnormal-looking growth.
  • Excisional biopsy: a scalpel is used to remove the entire growth.

Nearly all skin cancers are treatable if caught early. Many cancerous skin lesions can be removed completely at the time of the biopsy and no further treatment is necessary. Four types of treatments are standard for skin cancer:

Surgery: where tumors are cut from the skin in thin layers.

  • Radiation therapy: where high level x-rays or other types of radiation are used to kill cancer cells.
  • Chemotherapy: where drugs are used to stop the growth of cancer cells by killing them or by stopping the cells from dividing.
  • Photodynamic therapy: where drugs that are not active until they are exposed to laser light are injected into the veins.

Q: Where can I go for more information?
A: M. D. Anderson's Cancer Prevention Center provides consumers with information looking for cancer prevention and risk reduction guidance. Learn more at Additional information is available through the American Cancer Society webpage at and the American Academy of Dermatology at

M. D. Anderson Cancer Center in Houston has earned the distinct honor of consistently being ranked among the nation's top two cancer hospitals in U.S. News & World Report's "America's Best Hospitals" survey since its inception 15 years ago.


The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of News Medical.
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