Dr. Darrell Rigel discusses ongoing questions (and some answers) in the ongoing pursuit of photoprotection.
Darrell S. Rigel, MD, MS, Clinical Professor of Dermatology at Mount Sinai Icahn School of Medicine, New York, New York; Adjunct Clinical Professor of Dermatology, UT Southwestern; and Consultant Dermatologist at Cooper Clinic, Dallas, Texas
“We all know the primary cause of skin cancer is ultraviolet (UV) exposure. There have been a number of studies that have shown that over the years, and [there are also] studies out of Australia that have shown the regular use of sun protection over time lowers melanoma risk.1 So, that’s not a doubt anymore,” said Darrell S. Rigel, MD, MS, who presented “New Advances in Photoprotection” at Music City SCALE 2023 in Nashville, Tennessee.
But there are ongoing questions (and some answers) in the continuous pursuit of skin protection from UV exposure, said Dr. Rigel.
Sunscreen or Shade?
“One of the questions that has come up is ‘Which is better, sunscreen or shade?’ In a study our group published several years ago in JAMA Dermatology, we showed that shade alone is not enough.2 Sunscreen alone is better, but the combination of the two is best.”
How High is High Enough?
The FDA is considering a cap of 60+ sun protection factor (SPF). According to Dr. Rigel, the question is, will that be adequate and is that appropriate?
“There are reasons for the cap and reasons against it. My feeling at this point is that the cap is not beneficial for a couple of reasons.”
According to Dr. Rigel, sunscreen manufacturers would have less incentive to develop better sunscreens should the cap go into effect because “no matter how good their sunscreen is, it will still have to be an SPF 60.”
Another concern is that SPF ratings are based on 2 mg per square cm of coverage, said Dr. Rigel.
“Patients would look as white as a sheet of Xerox paper if that was the case. Nobody applies that much. People typically apply 20% to 50% of the recommended amount, so if you have an SPF 100 and are applying 20% to 50% of the recommended amount, you’re getting a 20 to 50 SPF in actual use. That’s the advantage of the higher SPFs and you wouldn’t really know that if you had a cap.”
Dr. Rigel was among the authors of a study showing SPF 100+ better protects against sunburn than SPF 50+ in actual use.3
“It was a split-face, double-blind study with blinded reviews. It turns out that the SPF 50 side of the face was 11 times more likely to be sunburned than the SPF 100. The bottom line is—especially at high UV conditions, like Vail, Colorado, where this study was done—the higher SPF had value.”
As a result, Dr. Rigel said he hopes the FDA doesn’t put an SPF cap on sunscreen.
Environmental Concerns
Oxybenzone is at the top of the list of sunscreen ingredients that is causing environmental concerns, said Dr. Rigel.
“In Hawaii they’ve banned oxybenzone and other areas have tried to ban it. Key West tried to ban it, but the Florida State Legislature overrode that ban saying that melanoma was a real problem, and the other problem was hypothetical.”
The reality is that we really haven’t seen an effect in vivo of oxybenzone causing coral bleaching and weakening of the coral reefs, said Dr. Rigel.
“If you have a petri dish with coral and you put concentrations of oxybenzone that are thousands of times higher than you get in a real-world situation then, yes, you get some problems with that. But also going against that risk hypothesis is the fact that if you look at where corals are currently having the problems, those are not the areas where you see the sunscreen washing off into the ocean.”
For concerned patients, he advises the use of an inorganic zinc or titanium sunscreen.
“But there’s really no data to show the difference between the two types on the environment.”
On a side note, news in recent years that some sunscreens contained traces of the carcinogen benzene is no longer an issue, said Dr. Rigel.
“You would get more benzene exposure by filling your car at a gas station once with the gasoline fumes than you would potentially get using sunscreen every day on your entire body for a year. And, in fact, the benzene has been removed, so this is a non-issue at this point.”
Homemade Sunscreens
There are a lot of homemade sunscreens out there, said Dr. Rigel.
“Basically, none of them work. People should not be using those.”
They should be using their sunscreens regularly, said Dr. Rigel.
“Steven Q. Wang, MD, one of my former fellows did a great study to show that to encourage regular use of sunscreen what you should do is put the tube of sunscreen on your bathroom sink countertop next to your toothbrush. When you brush your teeth, you’ll remember to put your sunscreen on. In his study, it increased sunscreen use by 20%.”4
Finally, the question that every patient asks dermatologists is, “Which sunscreen is best?” said Dr. Rigel.
“The answer is the one they’re going to use. I tell my patients to find one that is cosmetically acceptable, and one that they’re happy with.”
Disclosures: Dr. Rigel is on the advisory board at Beiersdorf and Johnson and Johnson Consumer Product Company. He is a consultant with Ferndale Laboratories.
References:
- Olsen CM, Wilson LF, Green AC, et al. Cancers in Australia attributable to exposure to solar ultraviolet radiation and prevented by regular sunscreen use. Aust N Z J Public Health. 2015 Oct;39(5):471-6. doi: 10.1111/1753-6405.12470. PMID: 26437734; PMCID: PMC4606762.
- Ou-Yang H, Jiang LI, Meyer K, et al. Sun Protection by Beach Umbrella vs Sunscreen With a High Sun Protection Factor: A Randomized Clinical Trial. JAMA Dermatol. 2017;153(3):304–308. doi:10.1001/jamadermatol.2016.4922.
- Williams JD, Maitra P, Atillasoy E, et al. SPF 100+ sunscreen is more protective against sunburn than SPF 50+ in actual use: Results of a randomized, double-blind, split-face, natural sunlight exposure clinical trial. J Am Acad Dermatol. 2018;78(5):902-910.e2. doi:10.1016/j.jaad.2017.12.062.
- Wang SQ, Xu H, Dusza SW, et al. Improving compliance of daily sunscreen application by changing accessibility. Photodermatol Photoimmunol Photomed. 2017;33(2):112-113. doi:10.1111/phpp.12292.