Tuesday, August 5, 2014
Be Careful What You Read
By: Dr.Gregory Bourgeois with Shelby Dermatology
There has been a lot of buzz regarding sunscreen shared in social media with an obviously mixed message. As a dermatologist, I recommend sun protection habits beyond sunscreen including hats, sunglasses, sun protective clothing, avoidance of peak hours during summer, and seeking shade when possible. I do this because we know that UV exposure adds up over the years and can lead to skin cancers such as basal cell carcinoma, squamous cell carcinoma, and, to some extent, melanoma. Chronic sun exposure also leads to photoaging – the wrinkles and dark brown spots and skin texture changes that patients often seek help to correct.
The following articles were shared with me by friends and colleagues. I’d like to examine them individually.
Spray sunscreens are a novel idea for sunscreen application. They make sense: it takes a ton of time to apply sunscreen so just spray it on. Many companies have come out with their version, and many consumers are buying them for their convenience. But, to be truthful, we really don’t know how well these work in the hands of the typical consumer. Many dermatologists are leery of their use because they feel that patients will not spray enough sunscreen on their skin to get the actual sun protection labeled, so they recommend spraying on hands first then applying. Also, perhaps the aerosol spraying of chemicals is harmful when inhaled, particularly the nanoparticles mentioned in the article. For now these have not been studied enough, so avoid use on children and stay tuned.
The article in the Daily Mail UK shows a glaring headline that sunscreen may NOT prevent skin cancer. Read on and you’ll find that they are speaking of melanoma in particular (why didn’t they just say ‘melanoma’ in the headline? A bit misleading to use the blanket generalization of ‘skin cancer’). They do summarize a recent article in the journal Nature that studied the use of sunscreen in preventing development of melanoma in mice that have the BRAF mutation, a mutation found in many melanomas. These sunscreen-protected mutant mice developed melanoma after exposure to ultraviolet radiation (albeit development of melanoma occurred at a smaller percentage and later than those BRAF mutant mice exposed to ultraviolet radiation that did not have any sunscreen protection). Although it has been studied many times with various results, there is still no solid evidence that melanoma is prevented by regular sunscreen use. It makes sense intuitively since many melanomas occur in patients with chronic sun exposure and history of blistering sunburns, but perhaps it is only risk reduction of melanoma with regular use of sunscreen. I think this Nature article drives home the point that sunscreen is only part of the protection strategy (remember the hats, the clothing, the sunglasses, the shade, avoiding peak hours).
The last article on RealFarmacy.com opens with this line “…women who avoid sunbathing during the summer are twice as likely to die as those who sunbathe every day.” This bold statement should have anyone at least questioning the validity of it. They quote a study from the Melanoma in Southern Sweden cohort published recently in the Journal of Internal Medicine. The cohort was composed of light-skinned Caucasian females in an area of the world with low UV due to latitude. This environmental geography is where a chronic low Vitamin D level could be an issue in leading to all-cause mortality. But one can’t deduce from this Swedish study the further accusations found in this RealFarmacy.com article:
The link between melanoma and sun exposure (dermatology’s dogma) is unproven. There’s no conclusive evidence that sunburns lead to cancer. There is no real proof that sunscreens protect against melanoma. There’s no proof that increased exposure to the sun increases the risk of melanoma.
For a great rebuttal see http://www.snopes.com/medical/myths/sunscreen.asp
The bottom line is that sunscreen works but is not perfect. It should be used as part of a strategy for skin cancer prevention, along with the aforementioned apparel, seeking shade, and avoiding peak sun hours. As always, visit a dermatologist to screen for skin cancer or to evaluate any suspicious appearing skin lesions.