Summer has begun, and that means picnics, outdoor festivals, beach time – and a whole lot of sun.
And although most people appreciate a natural dose of vitamin D, too much sun is a major health hazard.
Wynn Kao, an assistant professor of dermatology at GW’s Medical Faculty Associates, spoke with GW Today about how Washingtonians can best protect themselves from the sun’s harmful rays and detect warning signs for skin cancer.
Q: What are the best ways to protect yourself from the sun?
A: Apply generous amounts of broad-spectrum, water-resistant sunscreen. Wear protective covering, such as long sleeves, a wide-brimmed hat and sunglasses.
Q: What are the differences between UVA and UVB rays?
A: UVA is the longer wavelength (320-400 nanometers) form of ultraviolet radiation, while UVB is shorter (290-320 nanometers) and higher energy. UVB is relatively more important in causing skin reddening and sunburn, as well as in the development of skin cancer. UVA is less intense but penetrates more deeply into the skin. It is more important in skin aging and wrinkling but also contributes to skin cancer. Both forms can suppress the immune system.
Q: What SPF should people wear? How often should you reapply?
A: Use SPF of at least 30 and one that is broad-spectrum, which means it provides protection from both ultraviolet A (UVA) and ultraviolet B (UVB) rays. Reapply approximately every two hours, even on cloudy days, and after swimming or sweating.
Q: The Food and Drug Administration recently decided that manufacturers must make sunscreens protect equally against UVA and UVB rays in order to earn the designation of "broad spectrum." Does this decision benefit consumers, and why?
A: Yes, it does. Currently the SPF ratings only evaluate protection from UVB but not UVA. It is important that consumers be confident that sunscreens protect against both UVB and UVA, and the new FDA policy should help them do that.
Q: The FDA also will ban sunscreen makers from claiming their products are waterproof or sweatproof. What is the significance of this rule?
A: This will clarify exactly how resistant the sunscreen is to water exposure. "Water resistant" sunblook maintains its SPF level after 40 minutes of water immersion, while "very water resistant" is now used to classify sunblock that maintains SPF level after 80 minutes of water immersion. "Waterproof" is no longer permitted, as this would incorrectly imply that the sunblock could maintain SPF regardless of any duration of water immersion.
Q: Can people get harmful rays from the sun just walking a few blocks from the Metro to their offices each day?
A: Yes, especially between 10 a.m. and 4 p.m. from April to October. Intense intermittent exposure is thought to be an important risk factor for melanoma, the most serious form of skin cancer, because it damages your DNA, which can lead to cancer if your cells cannot repair it. How harmful the exposure is depends on the individual. People with fair skin and blue or green eyes have less pigment to protect them from the sun and are at much higher risk.
Q: Can harmful rays pass through your hair to your scalp?
A: Yes, while hair might absorb some ultraviolet energy, we do see precancerous and cancerous lesions on the scalp even in patients with dark, abundant hair.
Q: What are the main types of skin cancer, and what are their signs and symptoms?
A: The main types of skin cancer are melanoma, basal cell carcinoma and squamous cell carcinoma.
Basal cell carcinoma is the most common form of skin cancer and most common cancer of any kind, affecting approximately two million Americans each year, almost always on sun-exposed areas. These cancers arise in the basal cells, which line the top skin layer. It may look like a waxy or shiny bump or pimple or scar that doesn’t go away.
Squamous cell carcinoma is the second-most common skin cancer. It arises in the squamous cells that make up most of the skin’s upper layers. It is most common in sun-exposed areas but can occur on the lips or genitals. It can also look like a scaly or crusty reddish bump or patch or an open sore that itches and bleeds.
Melanoma originates in pigment producing cells called melanocytes and is the most serious form of skin cancer. If recognized and treated early, it is almost always curable, but if not, it can spread to other parts of the body and be fatal. Melanoma is responsible for the majority of skin cancer deaths. Melanoma most commonly looks like a mole that has an unusual shape, border, color, size larger than a pencil eraser.
Aside from occasional itching and bleeding, many skin cancers can have no symptoms of discomfort except for changing appearance, including growth, color change and asymmetry. See a dermatologist for anything on the skin that lasts for two weeks or longer and is itchy, bleeding, growing or changing.
Q: How can you be vigilant in being on the lookout for possible skin cancers?
A: Perform skin self-exams once a month. Finding skin cancers early allows us to cure them. These exams are especially important if you have been treated for skin cancer. Have a family member or friend check your back for changing lesions. Take photographs and see if anything is changing over time.
Q: Should everyone get a yearly mole check?
A: Yes! And people who have recently been diagnosed with skin cancer need to be checked every three to six months.
Q: What are some other negative side effects of sun exposure?
A: Sun exposure causes photoaging, which includes wrinkles, dark spots, droopy or leathery skin, as well as decreased function of the immune system. UVA light is most responsible for these side effects.
Q: What are the treatments for skin cancer?
A: Surgical excision, which is a procedure that cuts out the cancer and a border of normal-appearing skin, is the most common treatment and is performed in a dermatologist’s office under local anesthesia. Mohs surgery, also known as Mohs micrographic surgery, is a specialized surgery where the layers of cancer-containing skin are progressively removed and examined microscopically until only cancer-free tissue remains. Other treatments include cauterization, or burning the tumor; cryodestruction, or freezing the tumor; and photodynamic therapy, which involves applying a photosensitizing chemical to the skin that allows the cancer to be destroyed when exposed to specific kinds of visible light. If the cancer has spread beyond the skin, chemotherapy is used to kill the cancer cells in the body.