Skin cancer is the most common human cancer in the U.S., and its most serious type results in nearly 10,000 deaths each year. But do we take it seriously enough?
Having a "healthy fear" of skin cancers, most of which are preventable or curable when detected early, could save you time, money, pain, possible disfigurement and even your life. To learn more, we spoke with Susan M. Swetter, MD, professor of dermatology and director of the Pigmented Lesion and Melanoma Program at Stanford.
How do you convince people to take skin cancer prevention seriously?
Skin cancer will affect 1 in 5 Americans over the course of their lifetime, and rates of all types of skin cancer -- including keratinocyte cancers (basal cell and squamous cell carcinoma) and melanoma -- continue to rise.
It is estimated that nearly 65 percent of melanomas and 90 percent of keratinocyte cancers in fair-complexioned populations worldwide are attributable to sun exposure. Therefore, prevention through avoidance of excessive ultraviolet radiation (UVR) exposure is critical.
What types of skin cancer are there?
"Nonmelanoma" skin cancers include basal cell and squamous cell carcinomas, which arise from a cell type called the keratinocyte. As such, the term "keratinocyte carcinoma" is more accurate than nonmelanoma skin cancer, since there are other rare types of skin cancers that do not come from the epidermis (top layer of the skin). The latest evidence (from 2012) suggests that over 5.4 million cases of keratinocyte carcinoma will be diagnosed in over 3.3 million persons in the U.S., making this type of skin cancer the most common human cancer in our country.
Melanoma occurs much less frequently, with at least 160,000 cases diagnosed annually (including invasive and in situ types), but it is considered the most deadly skin cancer, with nearly 10,000 deaths projected to occur in 2017. Melanoma is now the fifth most common cancer in men and the sixth in women.
How dangerous are these skin cancers, and who is most at risk?
Most keratinocyte carcinomas are cured with surgery or other types of treatment and do not spread to other sites of the body. The exception is squamous cell carcinoma in immunosuppressed individuals, such as organ transplant patients who require drugs to lower their immune system function.
Melanoma is also generally curable when treated in its earliest in situ (intra-epithelial) or thin invasive forms. However, the difference between survival with as little as a millimeter in the skin (about the breadth of a piece of hair) is significant. For instance, estimated five-year survival for a person with a melanoma measuring 1 mm or less in thickness is >97 percent but drops to 70 percent or lower at a 4 mm depth.
The greatest risks for skin cancer development are fair skin phenotype with sun sensitivity, especially patients with red hair, blue or green eyes, and an inability to tan. A history of excessive sun exposure -- whether through natural sunlight or artificial UVR from tanning booths -- is a major risk factor, and the number and type of moles a person has can also contribute to melanoma risk.
What preventative measures can be taken to prevent skin cancer and melanoma?
Regular sun protection practices are critical to skin cancer prevention, beginning in infancy and early childhood. It is estimated that the regular use of sunscreen with sun protection factor (SPF) of 15 or higher during the first 18 years of life could decrease the incidence of keratinocyte carcinomas by nearly 80 percent over a person's lifetime. In a large, randomized, prospective trial conducted in Australia, regular sunscreen use significantly reduced the number of precancerous lesions called "actinic keratosis," squamous cell carcinoma, and melanoma.
Skin aging is also dramatically reduced by regular sunscreen use. Sun protective measures should also include avoiding tanning; reducing peak UVR exposure (during 10 a.m. and 4 p.m.) when possible; and wearing protective clothing, hats, and sunglasses.
Does early treatment matter?
Early detection and treatment of skin cancer makes a difference. For nonmelanoma skin cancer types, early diagnosis generally results in less disfiguring surgery and fewer treatment-related complications. The same is true for melanoma: early detection of thinner tumors saves lives.
Are there common misconceptions about the disease?
Most misperceptions regarding skin cancer relate to tanning practices. Tanning is your skin's way of protecting it against further sunburn, and any tan means that your cells have incurred DNA damage.
Sunless tanners, also called artificial tanners, are not harmful, because they simply stain your skin a darker color. However, sunscreens must be used with these agents to prevent skin cancer and sunburn.
It's important to note that new FDA sunscreen labels state that broad spectrum sunscreens (containing UV-B and UV-A filters) with SPF of at least 15 can "reduce the risk of skin cancer and skin early aging if used as directed with other sun protective measures." This message is posted on all sunscreen products and should be heeded by consumers.
In terms of vitamin D, which may have a number of health benefits, diet and supplements are a far safer way to maintain adequate blood levels, and any recommendations to increase sun exposure or use tanning booths to increase vitamin D levels are unfounded.
A modified version of this piece originally appeared on the BeWell @ Stanford website.
Previously: Stay sun-safe this summer with these sunscreen tips, It's never too early to protect your skin from sun damage, New skin cancer target identified by Stanford researchers and The importance of sunscreen in preventing skin cancer
Photo by Meg Sanchez