Skin cancer is the most common form of cancer in the world, but most cases can be cured if diagnosed and treated early.
Ashani Weeraratna, PhD, is the E.V. McCollum Professor and Chair in Biochemistry and Molecular Biology. A Bloomberg Distinguished Professor, she has an appointment in the Sidney Kimmel Comprehensive Cancer Center and is a member of the National Cancer Advisory Board.
An expert in melanoma and author of Is Cancer Inevitable?, Weeraratna studies the role age, race, and sex play in cancer development and a person’s response to treatment.
When it comes to skin cancer, a lack of accurate information is a big reason why people don’t take the proper precautions or don’t get diagnosed early enough for treatment to be effective. She hopes that increasing sun safety education and debunking common myths can help everyone understand and reduce their risks of skin cancer.
Sunscreen should be part of your daily routine all year round.
Sun protection isn’t just for sunny summer days or trips to the beach, Weeraratna says—though it’s especially important in those settings. Dermatologists and cancer prevention experts recommend that everyone use sunscreen throughout the year.
Even in fall and winter, when days are shorter, before you spend time outside, you should apply sunscreen to any exposed skin. It’s a common misconception that sunscreen isn’t needed on overcast days; in fact, up to 80% of the sun’s UV rays penetrate cloud cover and reach the earth. Additionally, snow can reflect up to 80% of the sun’s harmful rays and increase your chance of sunburn. Water and sand also reflect and increase exposure.
You can also reduce your exposure to UV damage by seeking shade—especially during midday hours when the sun’s rays are strongest—and wearing protective clothing like wide-brimmed hats, sunglasses, and clothing with UV protection factor (UPF).
The type of sunscreen, and how you use it, matters.
In the U.S., sunscreen is regulated by the FDA as a nonprescription drug to ensure safety and effectiveness. But there is a lot of variation among products.
“It’s really important that you use a broad spectrum sunscreen, because those protect you from both UVA and UVB rays,” says Weeraratna.
You should also pay attention to the SPF (sun protection factor), which represents how much sunburn protection the sunscreen provides. Experts recommend broad spectrum SPF 30 for everyday use for most people. “At SPF 30, you have about 97% protection, and anything higher doesn’t do much more for you,” says Weeraratna.
No matter what SPF you use, the protective effects of sunscreen will wear off after 90 minutes or so. Reapplying throughout the day is essential, especially if you’re sweating or spending time in the water.
Everyone, regardless of skin color, should wear broad-spectrum sunscreen year-round.
Melanin—the pigment that determines the color of your skin, hair, and eyes—helps protect the cells’ nuclei from getting sun damage. Because of this, people with lighter skin are more likely to develop skin cancer from sun damage. But melanin does not entirely prevent UV damage and is not a replacement for sunscreen or other sun protection.
A lack of sunburn does not mean a lack of damage.
Sunburns and tans are caused by UVB radiation. The sun emits both UVA and UVB radiation, both of which damage your skin and DNA and increase your risk of skin cancer. “I hear all the time, ‘but my burn turns into a tan,’” says Weeraratna. But both burns and tans are signs of damage.
While medications like ibuprofen can reduce some of the pain and inflammation caused by a sunburn, nothing can reverse the damage that burn represents. “It helps the appearance of the burn, but not the damage done to the DNA,” she explains.
Getting a “base tan” is not a safe way to protect your skin from sun damage.
It’s a common misconception that people with lighter skin can get a “base tan”—intentionally getting a tan, either from sun exposure or a tanning bed—to reduce their risk of skin damage or sunburn. The truth is, there’s no such thing as a safe UV tan.
“I often hear, ‘I need to get a base tan before I go to the Caribbean for a holiday,’ and I always respond, ‘would you smoke a pack of cigarettes to protect you from lung cancer?’”
UV lamps, like those used in tanning beds and nail salons, damage your skin and increase your chances of developing skin cancer.
There’s no shortage of research showing the risks of indoor tanning. Among the startling data compiled by the Skin Cancer Foundation:
- More people develop skin cancer because of indoor tanning than develop lung cancer because of smoking.
- More than 419,000 cases of skin cancer in the U.S. each year are linked to indoor tanning. More than half of these are basal cell carcinomas.
- People who have ever tanned indoors have a 83% increased risk of developing squamous cell carcinoma and a 29% increased risk of developing basal cell carcinoma.
- People who first use a tanning bed before age 35 increase their risk for melanoma by 75%.
Smaller UV lamps, like those used in gel manicures, also carry risk. In studying UV as a driver of premature aging, Weeraratna and her team needed a machine that could replicate the type of DNA damage caused by the sun. “We bought machines from all the big lab technology companies,” she says. “The machine that delivered the most accurately representative burn was a gel nail lamp from Amazon.”
Skin cancer can show up in places the sun never touches.
Acral lentiginous melanoma—the most common melanoma in people of color—is not caused by sun exposure, and there are no known ways to prevent it, so early detection is essential to increasing the success of treatment.
“A common mistake people make is not looking for melanoma in the right places,” says Weeraratna. “Skin cancer on people of color often appears in the nail bed, on the palms of the hand, or the soles of the feet.”
“Two years ago, Weeraratna was getting her toenails painted her usual pearlescent color during a pedicure when she spotted a stripe under her toenail and recognized it as possible ALM. She caught it early enough that it was premalignant, but the experience inspired her to learn more about the disease.”
Read: Acral Lentiginous Melanoma: The Overlooked Cancer
According to the Skin Cancer Foundation, the plantar portion of the foot is often the most common site of skin cancer, being involved in 30%–40% of cases.
Skin cancer can also appear on a person’s genitalia. While vulvar cancer is rare, it most commonly presents as squamous cell carcinomas and melanomas. Dermatologists may not check these areas without a patient’s request, making annual gynecological exams another important checkpoint for skin cancer.
Knowing your personal risk for skin cancer can inform the precautions you take.
Skin cancer can be caused by more than just UV radiation. According to Johns Hopkins Medicine, other things can increase your risk of skin cancer, including:
- A prior or family history of skin cancer.
- Having fair skin and northern European heritage.
- Exposure to coal, arsenic compounds, or X-rays.
- Being immunosuppressed.
- Being male.
- Smoking.
The risk of skin cancer also increases with age. You are also exposed to more UV radiation at higher elevations and at locations closer to the equator.
Most skin cancer can be treated effectively if caught early.
Experts recommend visiting a dermatologist annually and checking your whole body once a month.
“Noticing changes is what’s most important,” Weeraratna emphasizes. “You might notice a spot in your nail bed and not really think much of it. But it could be a melanoma. If it doesn't go away in a couple of weeks, it's a good idea to get it checked out.” She also points out that if a blemish or mole starts bleeding or itching, that’s a sign to see a doctor right away.
For patients at higher risk of skin cancer, dermatologists can create mole maps. Mole mapping uses digital photography to track changes in a patient’s skin over time and help detect conditions earlier, when treatment is more effective.
“Melanoma is one of those cancers for which therapy has improved so dramatically over the last 20 years,” Weeraratna says. “There’s a lot of doom and gloom around cancer, but I like to take a step back and recognize how far we've come in treating it.”
Aliza Rosen is a digital content strategist in the Office of External Affairs at the Johns Hopkins Bloomberg School of Public Health.
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