A new study found that there were no differences between the incidence of basal cell carcinoma and cutaneous squamous cell carcinoma when comparing daily sunscreen use to discretionary use.
One in five Americans develop skin cancer in the course of their lifetime. Basal cell and squamous cell carcinomas (BCC and SCC) are the two most common forms of skin cancer; both of which are highly curable if detected early and treated properly. Approximately 75% of skin cancer deaths are from another skin cancer, melanoma.
Between the years of 1982 and 2011, melanoma rates doubled in the United States. Whether this is the result of increased awareness and caution or the result of an actual increased prevalence is a matter of debate. Sun exposure remains as the major risk factor for skin cancer. Though, no randomized controlled trials have found that sunscreen prevents skin cancer.
Due to the rising rates of skin cancer, many people have become scared of the sun, leaving the population to face the harmful health effects of vitamin D deficiency. The Slip-Slop-Slap sun protection campaign in Australia provides a perfect example of the “heliophobia” that exists today. This campaign encouraged people to reduce sun exposure and protect themselves from skin cancer by slipping on long-sleeved clothing, slopping on sunscreen and slapping on a hat. All of these methods do block the sun, but in doing so, also block the synthesis of vitamin D. Since the campaign was introduced, the incidence of SCC and BCC in Australia has decreased. However, the incidence of melanoma and prevalence of vitamin D deficiency have increased. Finding a balanced approach to sun exposure has proven to be a difficult task.
A past study consisting of nearly 30,000 Swedish women determined that the mortality rate among women who avoided the sun was double compared to those with the highest sun exposure. These results led researchers to wonder if the benefits associated with sun exposure outweighed the risks.
According to a survey, 70% of adults report that they usually or always use protection from the sun, such as applying sunscreen, wearing sun-protective clothing or seeking shade. Recently, researchers wanted to find out if protection from the sun reduces the incidence of skin cancer, specifically BCC and SCC, as one would expect. In order to do this, the researchers reviewed a randomized controlled trial (RCT) that included 1621 participants. The RCT compared the daily application of sunscreen to the discretionary use of sunscreen among the general population in Australia. The researchers found that those who used sunscreen on a daily basis did not develop BCC or SCC at a lower rate than those who used sunscreen with discretionary use.
The researchers concluded,
“We did not find evidence for the effectiveness of daily sunscreen for preventing BCC or SCC compared with the occasional use of sunscreen.”
While the study produced interesting results, it consisted of a few limitations. Many of the skin cancer cases weren’t confirmed by microscopic examination of tissue, meaning there could have been false reports. Furthermore, the study did not assess the effects of sunscreen use on the incidence of melanoma, the deadliest form of skin cancer. Lastly, the study did not compare the daily use of sunscreen to never using sunscreen; therefore, it’s unknown whether those who never use sunscreen face an increased risk of developing BCC and SCC in comparison to those who use sunscreen.
The Vitamin D Council believes individuals should receive safe, sensible sun exposure. You should not burn. Instead, sunbathe in your swimsuit (or naked) during solar noon for about half the time it takes for your skin to begin to turn pink as this is the amount of time it normally takes to receive enough vitamin D for the day. For the remaining time spent in the sun, use sun protection.
Tovey, A. & Cannell, JJ. New research suggests daily sunscreen may not prevent certain types of skin cancer. The Vitamin D Council Blog & Newsletter, 2016.