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Skin cancer is the most common and deadliest form of cancer and sun exposure is a common risk factor. One in five Americans will be diagnosed with skin cancer in their lifetime and Florida has the second highest rate of melanoma diagnoses, behind California.

In Moffitt's second Ask the Experts Facebook Live event, oncologist Dr. Vernon Sondak answered your questions about skin cancer and the dangers of sun exposure.

Here are some abbreviated questions Dr. Sondak answered during his interview. Watch the video below for a complete recap of the Facebook Live event.

1. Are long-sleeved SPF tops (rash guards) enough to protect you from the sun or should you still apply sunscreen underneath? What should people look for when purchasing sun protective clothing? Is more expensive better?

You do get what you pay for to a certain degree. All clothing has some degree of protection from ultraviolet light. We call it the UPF, instead of the SPF we use for sunscreen. I like to start by explaining the basics: a white T-shirt right out of the bag has a UPF of about 6, which is about the equivalent of putting on a sunscreen of 6. That is not very protective. Some outdoor companies that make swimwear provide a UPF rating for their clothing. You know exactly how protective that piece of clothing is. I still recommend that people do use some sunscreen around and underneath this clothing, especially around the sleeves and the neck where the clothing might pull away a little bit. 

2. Moffitt Facebook follower Cheryl says she just started chemo for breast cancer; is there an extra precaution she needs to take before going out into the sun?

Some medications, not just chemotherapy, but all different kinds of medications can make people much more sun-sensitive than they would have been. You can take someone who might not burn for 30 or 40 minutes in the sun and have them burn in just a few minutes. We call that “photosensitization.” You should know in Florida if you are taking a medication, that could potentially make you more sensitive to the sun. There’s a variety of different medications, including some of the powerful anti-cancer drugs that we do use here at Moffitt, as well as other drugs that have nothing to do with cancer that can make your skin more sun-sensitive. Clearly, if you are immune-suppressed, if you have other medical issues, you may need to be extra careful about getting sunburn.

3. How necessary is it to wear sunscreen on a cloudy day?

Often it is more important on a cloudy day in some ways because people will be out in the sun and won’t realize they are getting ultraviolet exposure. Clouds, enough to cover the sun, do not screen out the ultraviolet radiation. If there are rain clouds, or if it is a thunderstorm, that is going to screen out the UV radiation. An overcast day is not screening out the UV radiation and people get just as burned but it sneaks up on them, they don’t realize they were getting the sun exposure. It is something we tell everybody to be very careful about.

4. Are there any early warning signs of skin cancer?

The earliest signs are usually things we associate with melanoma. The “ABC and D’s” are the concept we use to teach the early warning signs of melanoma. It won’t apply to basal cell or squamous cell carcinoma. The ABC and D’s are as follows:

A - Asymmetry
B - Border Irregularity
C - Variable Color or Very Dark Color
D - Enlarging Diameter (usually bigger than the eraser on the head of a pencil)

Those are some early warning signs of melanoma. Other cancers have different signs and not every melanoma shows those “ABC and D’s” signs. If you are paying attention to your skin, if you see something that is changing and not getting better, and you get it checked out, your doctor will be able to take care of it before it worsens.

Find out more about skin cancer screenings offered by Moffitt Cancer Center’s Mole Patrol in your local area.

5. Is sunscreen really waterproof?

It really isn’t waterproof. It’s water resistant, meaning it will stay on a little bit longer in the water or with sweating than a non-waterproof sunscreen. Water-resistant sunscreens are a good thing for the beach but we also remind people the water resistance goes in two directions. It doesn’t let water in and it doesn’t let water out as much. For some people, it affects their skin and they say, “Oh I can’t use sunscreen, it bothers my skin” but what they are really feeling is the sunscreen is blocking their pores a little bit and they might find that if they switch to the exact same sunscreen that was not waterproof, they like the feel of it on their skin better. Even if your sunscreen is waterproof and you just went in the water, chances are you’ve lost most of the sun protection and you need to reapply it. It’ll hold its protection in the water longer but by the time you come out, you need it again.

6. What is the best way to treat sunburn?

The best way is to prevent sunburn and that is the easiest thing. After you get a sunburn there is no way to undo that damage. Even long after the sunburn has healed, there is a lasting effect on your cells. Anytime your skin color changes, that is a sign of DNA damage. A tan or a burn, it doesn’t matter, if your skin changed because of exposure to the sun, it is a sign of DNA damage and it builds up over time and you can never get rid of it. Once you’ve got a sunburn, the best things are really just to make you feel better, they are not to really cure the sunburn. Keep it clean, cool it off, and keep it protected. If you do blister and peel, to protect the delicate skin underneath, that will get you through the acute episode. There is not much you can do to undo the damage.

7. What is the risk of melanoma coming back in the same area?

That depends. Melanoma is one of the most aggressive forms of skin cancer. Unlike a basal cell or squamous cell carcinoma, we are going to take a much wider surgery to minimize the chance of melanoma coming back at the same site. If the melanoma is picked up early, in general, the chance of it coming back in that spot after a relatively small surgery that can be done under local [anesthesia] is very low. If the melanoma is some place like on the face, even if it is picked up very early, we often find that there is so much sun damage to the whole face, that it keeps coming back around the edges not necessarily because the surgeon left it behind, but because the whole area has been affected and it is continuing to develop. Those can be particularly challenging, the melanoma on the face or on the back of the hand where there has been a large and repeated amount of sun exposure. There are some cases where it has been more advanced and it keeps coming back. The best answer is to get it early and then your chance of it recurring locally or anywhere else in your body goes way down.