Navigating UV Safety, Photodamage, and Next-Gen Protection: A Q&A With Kathleen Suozzi, MD

As UV Safety Awareness Month highlights the importance of photoprotection, dermatologists have an opportunity to reinforce one of the most effective strategies for reducing both photoaging and skin cancer risk: consistent, lifelong UV prevention. Although public awareness of sunscreen and sun safety has improved, misconceptions, inconsistent adherence, and cumulative UV exposure continue to drive preventable skin damage and skin cancer. In this Q&A, Kathleen Suozzi, MD, associate professor of dermatology at Yale School of Medicine, discusses the clinical signs of photodamage that warrant the greatest concern, emerging approaches to preventing and treating UV-induced skin damage year-round, and the latest advances in photoprotection—including the recent FDA approval of bemotrizinol.

Dermatology Times: Why is July's UV Safety Awareness Month still so important? What opportunities does it create for dermatologists and patients?

Suozzi: Obviously, as we're getting into peak summer, it's a great time to think about our UV exposure. While I do think there's better awareness about the need for UV protection, particularly in our younger populations, we're still underutilizing the best UV strategies, and I think oftentimes, when patients are coming to me concerned about their history of UV exposure, a lot of the damage has already been done. So making sure that younger populations are aware of the importance of UV exposure, even in childhood, is critical. And this is a great month to bring awareness to that.

Dermatology Times: When examining patients in clinic, what signs of photodamage concern you the most?
Suozzi: When we think about skin aging in general, the vast majority of skin aging is all from UV, and so when we think about the two categories, photo aging and skin cancer/precancerous change, there is a lot of overlap. In terms of precancerous change, the findings we're looking for are going to be precursor lesions on the skin. So the most common thing would be actinic keratosis, lesions that feel pink and gritty, almost like sandpaper. Actinic keratosis is a precursor lesion of squamous cell carcinoma. Each one of these lesions is not destined to go on to be a skin cancer, somewhere between 1 in 100, 1 in 1000 risk, but when patients have multiple (more than 10), where there's broad areas of involvement, their risk of skin cancer increases significantly. So there are other signs of photoaging that are also important. So when I'm evaluating a patient, whether it's in my skin cancer clinic or in my aesthetic clinic, the other signs of photoaging, such as dyspigmentation, lentigines, brown spots that are collecting on the skin, and solar elastosis. I often describe that to patients as that cobblestoning texture that you can see in the skin, as the collagen kind of becomes more, instead of fibrillar and woven, balled up and bumpy...volume changes, loss of elasticity. While these are not precursor lesions themselves, this type of photoaging, typically associated with a history of UVA exposure versus UVB exposure for the more precancerous side, these are both carcinogens, and so the more photo damage you have of any type is telling me that about your risk profile.

Dermatology Times: Are there any recent advancements that can help reverse cosmetic and underlying sun damage?
Suozzi: I'm a big believer in preventative therapies and I think we are having a lot more understanding of things that we can do for prevention. Starting first on the cancer side...when we talk about field therapy, this is the concept of treating broad areas of skin for precancerous change. We know that if you took a biopsy of someone's skin and looked at the mutations, it's like a quilt of precancerous mutations lurking there. And as we get older, our immune senescence, or our body's immune system's ability to kind of knock down these precancerous mutations or treat early skin cancers, decreases. Our body's ability for DNA repair mechanisms is lower. We get fibroblast senescence as well, and so in order to correct damage as these pathways are becoming less efficient, we have to sort of trick the body in certain ways. So our traditional field therapies were using chemotherapy creams to treat precancerous change, like Efudex, and now we have newer protocols where we can combine with calcipotriene to decrease the duration of treatment. These are kind of more direct field therapy approaches. Also under this umbrella would be photodynamic therapy, where again we can treat broad areas of precancerous change, kind of seeking out the damaged skin cells and leaving the more normal skin cells alone. What I do think is interesting is this emerging field in terms of looking at the skin more completely. So we already mentioned the immune system, but what's the role that the dermis plays? And we have more evidence that resurfacing lasers, which are not just getting epidermal cells to turn over, but also modulating the dermis and creating a healthier dermal milieu, are likely preventative for non-melanoma skin cancer as well. Understanding that, I think, is where there's some interesting science going. Is this the interplay between the immune system and the dermis and the epidermis, or is the ground substance of the dermis, important collagen, blood vessels? So there are a lot of components where I think we're going to learn a lot: it's not just the mutations that live in the epidermis, it's the whole ecosystem.

Dermatology Times: What are the biggest misconceptions you hear about sunscreen? How do you address these with patients?
Suozzi: I hear a lot of misconceptions about sunscreen. There's sort of the big obvious ones like sunscreen causes skin cancer and we're dispelling rumors like that a lot. In more recent years, there have been some concerns around health risks related to skin cancer. So, as has been reported, there was a lot of controversy a few years ago about bloodstream absorption of sunscreen, the chemical sunscreen components, and so there was a lot of fear around that. But I'm always reassuring patients...these are sunscreen ingredients we've been using for decades. We have no indication that there's any risk to human health from these very low levels in the bloodstream. The other thing that commonly comes up is the damage has all been done. Sun protection now...what's that going to do? So we're counseling patients that yes, well, we can't reverse the damage of your youth. But good sun protective strategies now are going to minimize the number of skin cancers that you have moving forward. So those are some of the big ones. In terms of counseling, I think it's really just about employing common sense strategies and looking beyond just applying SPF as your only level of protection. We have a lot more options now with UPF clothing, sun-protective clothing. Telling patients who think that a baseball cap is enough for facial protection that it's not protecting anything on the sides of your face and your lower face. I do spend time with my patients counseling about the use of sunscreen, concerned about, well, what is the best sunscreen? Which product should I be buying and using? And I always say the best product is the one you're going to wear, and the one that you're going to use, and that could be different for different individuals based on your skin tone, based on whether you're acne-prone, etc. And so sometimes it's just a personal trial and error of different products. But I think the biggest mistakes people make are not applying with regularity. I tell patients every day, even in the winter...commuting, driving to work, gardening, daily activities of daily life all add up. But the other issue is if you only apply in the summer and not the winter, it doesn't become part of your routine that you just do reflexively, so I am always encouraging that. And then I think the other common question I get is around what is the SPF level that I have to use, and counseling patients that SPF protection is nonlinear. I usually tell patients SPF 30 or above because at SPF 15, you're getting about 93 to 95% coverage. At SPF 30, it's about 97% of UVB protection. It's a small incremental change, and as you go up in SPF, in order to achieve those higher levels of SPF, the product often can become less wearable, which will then have an effect on use. And again, with the benzene levels, in terms of the risk to human health, really unsubstantiated there. It could be detected, but what does it mean? The aerosol products were more of a concern, so that's a simple thing that you could counsel patients on. You can avoid the spray sunscreens in favor of the cream-based ones or lotion-based ones.

Dermatology Times: Looking ahead, what should dermatologists be looking forward to regarding UV protection, detection, and treatments?
Suozzi: Well, I'd be remiss if I didn't mention the recent FDA approval of bemotrizinol, which is the first addition to the OTC monograph of the FDA in over 20 years. So this is big, big news. Bemotrizinol is a chemical sunscreen that has been around in Europe and Asia for over 20 years. So it has a very good safety profile. But why it's so exciting is for the following reasons. Number one, it has broad UVA and UVB coverage in a single molecule. It is photostable, so many of our chemical sunscreens are photolabile, so they break down while you're wearing them in the sun, whereas bemotrizinol has good durability. It's cosmetically elegant, sheer, wearable, and low risk of irritation. And then going back to that concern about bloodstream absorption because it's a larger molecule, the risk of absorption is lower too. So it's kind of hitting all the things that we look for in ideal sunscreen, so can't wait for that to come to the U.S. market, which should be soon. That approval was just last month. And I think I also touched on this before; in terms of understanding how we can use energy-based devices to decrease skin cancer risk, that is very exciting, and we are also making advancements in terms of skin cancer treatment. As a Mohs surgeon, I'm surgically removing skin cancers every day, but I look forward to the day when we have medical therapies that make the need for surgery less, and I think we are moving there. Our use of immunotherapy and PD-1 inhibitors has really changed how we approach skin cancer, and the burgeoning use of neoadjuvant treatments for skin cancer with PD-1 inhibitors, and looking forward to interlegional treatments and studies that are ongoing in that realm, I think is going to really change how we're treating skin cancers as well.

[Transcript has been edited for clarity]