Does a Suntan Protect Against UV Rays?Jul 29, 2014
Does getting a rich golden-brown tan offer protection from dangerous skin-cancer causing UV rays? Dr. Doug Grossman from Huntsman Cancer Institute describes suntanned skin on a molecular level. He discusses the effects of sun exposure on DNA, tanning beds and different forms of skin cancer.
Interviewer: Suntans. Do they offer protection from skin cancer? We're going to examine that next on The Scope.
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Interviewer: We're with Dr. Doug Grossman. He's an expert in early diagnosis and treatment of skin cancer at Huntsman Cancer Institute. So I need this answer from a professional, from the guy that knows. I've always been under the impression if my skin starts tanning it's the natural response to the sunlight to let less sun in so that actually is giving me more protection. Is that accurate or not?
Dr. Doug Grossman: Well it's true that the suntan is a natural response of the skin trying to protect itself from the damaging UV rays and so actually the UV exposure generates a signal response in cells in the skin that causes more pigment to be made and this ultimately does protect the skin and so if you do have a suntan then you're going to be more resistant to future sun burning.
The problem is that you're also damaging the skin in this process and in fact the sunburn or suntan response is actually an indicator of damage to the DNA. What happens is the UV rays interact with the DNA and initiate this response that signals the cells to make more pigment but it's actually a reflection of that damage that you're incurring. And so even after a few weeks if the sunburn, the tan has resolved, that damage has still been done. And it can accumulate and persist for many years.
Interviewer: So gradually building up my suntan to prevent skin cancer, it could prevent a sunburn.
Dr. Doug Grossman: Right.
Interviewer: But the damage is still happening to the skin that could cause skin cancer. I'm getting no protection from it from what I understand. Is that correct?
Dr. Doug Grossman: Right. That's correct.
Interviewer: So what does that mean?
Dr. Doug Grossman: The tan is going to protect you against some future UV exposure but it would be better to not incur that exposure and damage in the first place.
Interviewer: And also, like wear long sleeves or wear some sort of a sunblock or something of that nature would be much better, right?
Dr. Doug Grossman: Right. Well, I tell patients if they want to have a tan and look tan the safe way to do that is to apply topical products or a spray tan and they can look quite realistic and that's totally safe. Artificial tanning in that way doesn't provide any protection against future exposure but that's the safe way to look tan. We really discourage patients from using tanning booths. We know that tanning booths increases skin cancer risk, it at least doubles melanoma risk and so we definitely discourage that.
Interviewer: I seem to remember at a tanning place one time the guy was telling me, "Oh no, this is okay because the damaging rays aren't in the suntan booth."
Dr. Doug Grossman: Well, generally in the tanning booths they use longer UV wavelengths that are lower energy so it doesn't cause sunburn but does initiate the tanning response and you get delayed tanning.
Interviewer: Which goes right back to what you said earlier is that that's an indication that you're getting cell damage.
Dr. Doug Grossman: Correct.
Interviewer: And that cell damage, so we all love our tan so much let's get into this cell damage a little bit more because I feel as though maybe if people heard what's really going on and how damaging it can be they might, you know, make a different choice. I've heard it described as bullets to the DNA.
Dr. Doug Grossman: There are different ways that UV can damage the skin. The UV can directly interact with the DNA and damage it in that way. This could result in mutations and so that when the cells divide-
Interviewer: Which all cells do. That's what cells do.
Dr. Doug Grossman: That's right. That's right. Particularly in the skin because the skin is always turning over and so you can introduce mutations that way. UV radiation also generates what we refer to as oxidative damage. These are chemical species that are generated in the skin upon UV exposure that damage all parts of the tissues: the proteins, the cell membranes. So there's that type of damage as well.
Interviewer: Somebody might think, "Well, I've damaged my skin. It dies. It sloughs off." But what happens is when that cell divides now you've got these mutations that could lead to skin cancer. Am I making...
Dr. Doug Grossman: Right. And so again the skin does turn over. Many of the cells that are dividing will ultimately die and be shut off. Changes in those cells are not going to result in skin cancer. However, there are what we call skin stem cells that are very long-lived that give rise to the cells that ultimately continue to grow in the skin and you generally don't lose those cells. And so if those cells accumulate this damage and these mutations they can ultimately give rise to skin cancer.
Interviewer: And how bad is skin cancer?
Dr. Doug Grossman: It's a range. It's a spectrum. Many skin cancers if they're detected very early are quite easy to treat and they are very localized in the skin and we can remove those with a small surgical procedure.
Interviewer: And I'd imagine once you start getting that it's going to continue because those cells are damaged.
Dr. Doug Grossman: If you get skin cancer in one location then your risk for getting it in another location increases because you have all these both genetic environmental risk factors that have led to the first skin cancer. We know that patients that have a skin cancer generally about half of them will get another one within the next couple of years.
Dr. Doug Grossman: That's primarily non-melanoma skin cancer. The melanoma skin cancer which is much more serious...
Interviewer: More on the other end of the spectrum.
Dr. Doug Grossman: Because it can spread can be a lot more unpredictable. That can occur in young patients, it can occur without much warning. About a third of melanomas are not related to sun exposure. And so we advocate all patients to monitor their skin on a monthly basis. Anything new or changing should be looked at. But we do know that over two-thirds of melanomas are related to sun exposure.
Interviewer: Any final thoughts on this topic?
Dr. Doug Grossman: I think my main message would be, be aware of your skin. It always surprises me how often we pick up melanomas in patients that had no idea that something was on their back or somewhere else on their skin that just because they weren't monitoring. I recommend again once a month that patients look at their skin, have someone else look at your scalp, look at your back, the areas that you can't monitor well on your own. Anything new or changing or that looks different from other spots on your skin would be something to get checked out.
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