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Melanin is the pigment that shades our skin and protects it from harmful radiation in sunlight. Because it is naturally dark, melanin absorbs light, including much of the ultraviolet energy in sunlight. But it can only absorb so much—when it reaches capacity, the skin begins to burn.

What Causes Melanoma?

Melanoma occurs when melanocytes, the skin cells that produce melanin, grow in an unchecked manner. These can appear as new and unusual dark growths or as a change in an existing mole.

Most cases of melanoma can be attributed to sun exposure or ultraviolet light from artificial sources—tanning beds or light therapy for certain skin conditions. Repeated exposure to ultraviolet light can scramble the DNA in our skin’s pigment cells, leading to cancerous growths.

It’s important to remember that this skin cancer can occur in patients of all racial and ethnic backgrounds. Melanomas can even occur in areas with limited exposure to the sun, like the palms of hands, soles of the feet, beneath fingernails, in the mouth, and even within the intestines or vagina. It can even occur at the back of the eye! Because it’s not purely due to sun exposure, you want to pay attention to any new, changing, itching, or bleeding dark marks.

Know Your Risk

Patients with fair skin, red hair, and blue or green eyes who have a history of repeated sunburns or tanning bed use, particularly in their youth, are at significantly increased risk of developing melanomas. It’s especially vital for parents to protect their children—UV damage is especially harmful in the childhood years and impacts skin cancer development later in life.

A deeper skin complexion doesn’t render you immune to melanoma, however. Continuous exposure to ultraviolet light, as well as random genetic mutations, may still spur cells to become cancerous. So regardless of skin type or skin tone, it’s important for everyone to protect themselves.

There may also be a predisposition within some families for the development of melanomas. The risk of contracting melanoma skin cancer may be higher in people whose parent or sibling had melanoma, and may also be associated with other genetic syndromes that predispose individuals to developing cancers. In addition, we know that people with many moles have an increased risk of developing melanoma.

Finally, melanocytes can also be affected by hormonal changes. If you notice a changing or bleeding mole during pregnancy, consider having the lesion checked for malignancy.

The Importance of Sunscreen

Many cases of melanoma skin cancer are preventable, simply by using common senseand that means avoiding the sun and applying sunscreen.

Two kinds of ultraviolet light are present in sunlight: UVA and UVB. In sunscreen products, sun protection factor (SPF) ratings target UVB rays, the cause of sunburn. UVA rays are less likely to burn us, and more likely to cause a suntan—but, like UVB, UVA can also cause DNA changes within our skin cells.

When you purchase sunscreen, it’s important to look for the words “broad spectrum” on the label, to assure that the product blocks both UVA and UVB rays.

What do those SPF numbers mean on a sunscreen product? Sunscreens are rated according to how much sun they block. To determine the SPF number, product developers consider how many seconds a patch of skin with the sunscreen applied can remain in the sun before it begins to turn slightly red (say, 300 seconds). That number is divided by the number of seconds it takes for the skin to burn slightly with no sunscreen applied (say 10 seconds). So, in this scenario, 300 is divided by 10, for an SPF of 30.

Of course, any use of sunscreen is better than none—but users must be sure to apply the product correctly! We have very reliable data that shows most people apply only 1/4 of the sunscreen needed to protect their skin…and using too little can significantly decrease the product’s effectiveness. This particularly applies to spray products, which don’t cover as well as lotions.

In a laboratory setting, SPF 100 isn’t much more effective at blocking UVA/UVB than SPF 50, but in real-life application studies, patients have better outcomes when using the higher SPF. I recommend that my patients use at least SPF 50, because it offers a better margin of protection for people who don’t apply enough.

Also, don’t forget to reapply regularly, according to directions—sunscreen loses its effectiveness as it’s absorbed or broken down by skin oils, or as we sweat and swim.

The Best Type of Sunscreen

My patients often ask me what’s the best product to protect skin from the sun. The best sunscreen is the one you’ll wear!

But, when it comes to greatest effectiveness, dermatologists favor products that contain zinc oxide. Dense, white, and nearly opaque, it stays put and reflects a large portion of the sun’s rays. For optimum protection, choose a sunscreen with zinc oxide as its active ingredient.

Besides applying sunscreen, wearing a hat with a wide brim can protect the head and neck. Long sleeves safeguard the arms. Sunglasses shield eyes and eyelids but be sure the glasses are UV-rated. And staying in the shade offers better full-body protection.

These steps are important regardless of season. Even in winter—playing in the snow or on the ski slopes—you need sunscreen. UV light reflects off snow so you can still get a sunburn in the winter!

Melanoma skin cancer can be aggressive and dangerous. But it’s very treatable, if caught early. Keep skin safe and healthy with advice from Dr. Min Deng. https://bit.ly/3u7bpRk via @MedStarWHC
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Signs of Skin Cancer

Although melanoma is less common than other types of skin cancer, it can be aggressive and ultimately much more dangerous. Of the 200,000 Americans diagnosed with melanoma each year, as many as 7,000 don’t survive.

But caught early, melanoma is actually quite treatable.

I recommend that patients take note of any existing spots on their skin, then check regularly to take note of anything new that develops. If you notice any “ugly ducklings” on your skin—that is, spots or moles that seem out of the ordinary—remember your ABCDEs:

  • A is for Asymmetry. Is a portion of the spot different from the rest of it?
  • B is for Border. Does it have an irregular, scalloped, or poorly defined border?
  • C is for Color. Is it varied in color, possibly including multiple shades (tan, brown or black, or areas of white, red, or blue)?
  • D is for Diameter. Keep a sharp eye out, as melanomas can start very small. Seek attention from a dermatologist for any spot larger than a pencil eraser.
  • E is for Evolving. Besides looking different from other spots on your body, has the spot changed size, shape, or color over time?

Any one of these indicators could be a good reason to reach out to your family doctor or dermatologist for guidance. Evolving spots are among the most important warning signs—and, for that reason, be sure to observe carefully…but not too frequently. If you study the spot daily, you may actually be less likely to notice a change. Assess spots no more than once per month.

The scalp is particularly prone to suspicious spots, especially in older men with thinning hair. Yet patients often neglect to examine this area. Ask your hair stylist or barber to report any changes to your scalp. And be vigilant about new moles that appear after age 40. New growths are less common at this age and should be investigated.

Diagnosis and Treatment

Most of us can tell if a spot on our skin seems out of the ordinary. When one of my patients reports a suspicious spot, more often than not, the concern is justified.

To understand what we are dealing with, we remove suspicious cells in an outpatient procedure (performed with local anesthesia to numb the area) and submit the cells for lab analysis.  Biopsy is the most reliable way for us to verify if cells are cancerous and enables us to determine the stage—or depth and spread—of the melanoma.

The easiest-to-treat melanomas are shallow, limited to the uppermost layer of skin. More concerning lesions are those that penetrate the skin more deeply. The most serious are those that have spread into the lymph nodes, where they create a potentially life-threatening situation.

To treat melanoma, we typically begin with surgery, removing the lesion and a margin around it to eliminate as much cancerous tissue as possible. In early-stage disease, surgery is often enough.

If we become concerned about systemic involvement, we can add immunotherapy, using a class of drugs known as immune checkpoint inhibitors that direct the body’s natural defenses to target cancerous cells.

Why Choose Our Team

Here at MedStar Washington Hospital Center, the Dermatology team works very closely with medical oncology, radiation oncology, and other experts across MedStar Washington with advanced knowledge and experience at treating cancer. Together, this multidisciplinary team is able to do amazing things for our patients.

We’re also part of the multi-disciplinary tumor board at the Georgetown Lombardi Comprehensive Cancer Center. In order to develop the best possible plan for each of our skin cancer patients, every case receives full consideration by the board members, who represent many specialties. The team has access to the most current knowledge and clinical trials in our fields, and many of our team members are also engaged in research.

So, if you notice a strange spot or growth on your skin, remember—it’s never too soon to reach out to your primary care physician or dermatologist. I can’t emphasize enough: if you see something out of the ordinary, act quickly. Like other cancers, the sooner we diagnose melanoma and other skin cancers, the easier it is to treat them effectively.


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