On Sunscreen and Skin Cancer

In 1903, Dr. Auguste Rollier opened the world’s first sun clinic at Leysin offering a place where sunlight was seen as a treatment for disease. Well into the 20th century, tanned skin was not only an indicator of health, but was fashionable as well. In recent years, outdoor tanning as well as the use of tanning beds have drawn attention for their potentially harmful effects. Skin cancer is the most common form of cancer in the United States with nearly one million cases diagnosed each year. Though other risk factors can contribute to the development of skin cancer, one’s exposure to ultraviolet (UV) radiation can speed their progression. By making sure to apply sunscreen, wear protective clothing, and limit time spent in direct sun, individuals can decrease their likelihood of developing skin cancer.

UV rays are a type of invisible radiation that comes from the sun, tanning beds, and sunlamps. There are three kinds of UV light: UVA rays are present year round and penetrate deep into the surface of the skin, damaging the cells beneath and causing signs of aging. Though UVA radiation can contribute to skin cancer, UVB rays, which cause sunburn and tanning of the skin and are more prevalent during the summer months, are also most often responsible for the development of skin cancer. UVC rays, are blocked by the ozone layer, but would cause sunburn with only brief exposure, while prolonged exposure would be fatal. Tanning beds primarily emit UVA radiation, which is the least harmful, but a 2006 study indicated that the use of tanning beds before an individual is 30 years old is associated with a 75 percent increase in melanoma risk.

Excessive UV exposure frequently leads to erythema, or sunburn, as well as causing a darkening and thickening of the outermost layers of the skin, which differs from a sun tan. Chronic exposure to any UV radiation can cause degeneration of the cells, fibrous tissue, and blood vessels of the skin, and may eventually contribute to the development some types of skin cancer. The primary symptom of skin cancer is a mole or other growth on the skin. The “ABCD system” is frequently used to help individuals understand what to look for when determining if a skin growth is cancerous. Asymmetry, when one half of the area is different from the other; Borders, irregular edges to the growth; Color, changes in color from one area to another; and Diameter, when the growth is larger than a pencil eraser; are all indicators that a lesion should be examined by a dermatologist. Some experts also make note of the “E factor” associated with skin cancer development – the Evolution or changing of the lesion.

The two most common types of skin cancer, basal cell and squamous cell carcinomas, also called non-melanoma skin cancers, can be caused by exposure to ultraviolet (UV) light. Though they are often curable, the process of surgical removal can be painful and disfiguring. According to a survey from the American Society for Dermatological Surgery (ASDS), there was a 10 percent increase in the number of surgical procedures related to skin cancer between 2007 and 2009. Melanomas are often malignant and are a more dangerous form of cancer, and 65 to 90 percent of them are caused by UV exposure.

To reduce an individual’s risk of developing skin cancer, experts recommend a number of measures that can be taken, including limiting the amount of time spent outdoors, particularly between 10AM and 4PM when UV exposure is highest in the continental United States. In addition, though it does not completely eliminate an individual’s risk of developing skin cancer, the use of sunscreen can help to decrease the risk. According to a U.S. sunscreen study conducted by Neutrogena, only 18 percent of American adults use sunscreen regularly, and only 48 percent of those reapply sunscreen when needed. Though the American Academy of Dermatology (AAD) suggests that consumers apply enough sunscreen to fill a shot glass, according to Jeffery Dover, president of the ASDS, consumers often do not apply enough for the products to be effective. The AAD reports that individuals frequently do not use enough sunscreen to adequately protect them from UV rays, and suggests the use of products with a sun protection factor (SPF) of at least 15 year round and 30 in the summer. SPF refers to the ability of a product to block UV radiation from reaching the skin, however the amount of protection does not increase proportionally with the SPF number and layering multiple SPFs does not result in protection equal to their sum. In order to ensure that sunscreens are most effective, they should be applied at least 20 minutes prior to sun exposure and only products stating that they provide UVA/UVB or “broad spectrum coverage” should be used.

In order to increase the use of sunscreen, public health officials have begun seeking new ways of increasing sun safety awareness. In one study, researchers found that using text messages to remind individuals to apply sunscreen when going outside, and reapply it following swimming or exercise increased its use. Sun protection has also advanced beyond the standard lotions, creams, and sprays, and now also includes clothing treated to provide UV protection. Most recently, a 10 percent tax was implemented on the use of indoor tanning services, underscoring the fact that even indoor tanning can be hazardous. With these new measures in place and continued improvements in sun protection technologies, researchers hope that it may be possible to prevent some skin cancers from developing.

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