The epidemic of skin cancer in the United States is often in the news. It’s worth knowing how these trends are changing over time.
Since the 1960s, the incidence of skin cancer has increased by 5 to 8 percent annually. The increase is in all sorts of skin cancers, but particularly for melanoma.
Overall, the lifetime risk of getting melanoma is about 2 percent (1 in 50) for whites, 0.1 percent (1 in 1,000) for blacks and 0.5 percent (1 in 200) for Hispanics. Unlike other cancers, melanoma is common in younger people.
Skin cancer comes in several flavors, and the most common are:
•Basal cell carcinoma — a locally invasive tumor that rarely spreads inside the body.
•Squamous cell carcinoma — a locally invasive tumor that may spread to lymph nodes if left untreated. This tumor is most dangerous on the head and neck.
•Melanoma — a tumor that may quickly spread from its original location to the lymph nodes, lungs or elsewhere in the body. Melanoma accounts for 5 percent of skin-cancer cases but a large majority of skin-cancer deaths.
Basal cell carcinoma and squamous cell carcinoma, when caught early, can be treated and rarely cause lasting harm. Melanoma, on the other hand, can spread quickly at times, even before it is detected. Being checked by a dermatologist or qualified health provider can help identify these problems as early as possible.
Risk factors we can change
There are several risk factors for skin cancer and for melanoma in particular. If you have one of the following in your history, you are at an increased risk:
•History of sunburn, particularly if you’ve lived in sunny or high-altitude climates
•Multiple moles or irregular moles
•Fair skin, particularly with blond or red hair, light-colored eyes and freckles
•Melanoma in a first-degree relative (sibling, parent, child)
•History of melanoma in the past
•Weakened immune system
Clearly, sun exposure is the easiest risk factor to change. So what are the best ways to avoid strong sun exposure?
Avoid sun exposure between 11 a.m. and 3 p.m. Ultraviolet (UV) light is strongest at that time of day.
Wear sunscreen year-round. Damage can come from cumulative small doses, as well as one sunny day.
Wear protective clothing. New textiles can have an SPF of up to 50. And don’t forget sunglasses.
Avoid tanning beds. These emit only UVA, which penetrates deeply into skin to cause precancerous changes.
Be aware of sun-sensitizing medications. Certain antibiotics, anti-inflammatories and acne medications like Accutane can make skin sensitive to sunlight.
Check your skin regularly. Schedule an annual skin check if you’re over 40 or have risk factors for melanoma.
It’s never too late to start
Looking back on years spent in the sun, it’s easy to wonder if starting with sun protection today would make a difference. Fortunately, a study of high-risk patients in Germany shows that skin-cancer development decreases after only 2 years of sunscreen use.
These patients were given free bottles of SPF 50+ sunscreen to use on the face, neck, hands and arms. After two years, people using sunscreen five to six times weekly had a decreased risk of both squamous cell carcinomas and basal cell carcinomas, and no patients in the study were diagnosed with melanoma.
The best sunscreens?
Broadly, all sunscreens can be divided into physical blockers (sunblock) that reflect ultraviolet light, and chemical blockers (sunscreen) that absorb ultraviolet light and re-emit it at a different wavelength.
Sunblocks like titanium dioxide and zinc oxide are very safe (even for small children) but can be more difficult to use if they look white or feel greasy.
Sunscreens — with active ingredients like avobenzone, salicylates and newer compounds like Mexoryl — can feel “lighter”’ and less greasy or opaque on the skin.
People without sensitive skin can use most sunscreens safely. For sensitive skin, titanium and zinc-based products are better tolerated. These ingredients are often found in baby sunscreens, and newer technologies can make them more comfortable to use.
And with the new availability of powder-based sunscreens, reapplying can be simple, even on the face.
The question often arises, why are there so many SPF numbers? Is there really a difference between SPF 10 and SPF 80? It turns out that under perfect, laboratory use there is little difference. However, in real life most people use only a quarter of the sunscreen used in the lab. In this situation, SPF 8 turns into SPF 2, and even SPF 30 is only equal to about 8. Add to that taking on and off clothing, toweling off and lying on a lounge chair, and a lot of sunscreen is left behind.
For a sunscreen to properly work, it needs to be present in adequate amounts so the SPF 80 just adds an extra level of protection.
Getting enough vitamin D?
All people need adequate vitamin D intake, and its activation in the body depends in part on the sun. For that reason, some endocrinologists promote some sun in a daily routine. The challenges are that we do not always get the same amount of sun each day, and in the Pacific Northwest, almost no one gets enough sun to maintain adequate vitamin D levels.
Instead of trying to get enough vitamin D from sunny summer days to last all year (which we can’t do), most endocrinologists and nutritionists recommend supplementation with vitamin D-rich foods like fish, fortified milk, very rich cod-liver oil or oral capsules.
Skin cancer is common, becoming even more so year after year. The best approach is prevention, but if that’s not possible, it can be caught early.
Fortunately, the skin is a very visible and accessible body system. People should check themselves monthly after the shower, get anything new or changing checked, and consider an annual visit to a dermatologist.
DR. KENDRA BERGSTROM is a dermatologist at Pacific Medical Center. Pacific Medical Centers (www.PacMed.org) has locations on Beacon Hill, First Hill and Northgate.